Having a highly efficient and reliable drive system increases production and provides peace of mind. Whether you require fluid couplings or a customized drive package, Voith is your partner of choice. We assist you in gently accelerating your driven machine, owing to the hydrodynamic principle, thereby extending the life time of your system. At the same time, torque is limited, load sharing is facilitated and torsional vibrations are dampened. The coupling protects the drive system from damage even under extreme operating conditions, reducing downtime and ensuring a continuous production process. Furthermore, our drive solutions are reliable and specifically tailored to each drive system from individual couplings to complete drive line solutions. The transmittable power ranges from 300 W up to 6 MW. Voiths product portfolio includes constant-fill fluid couplings, fill-controlled fluid couplings, fluid couplings for diesel engines and customer-specific drive solutions.
Furthermore, our drive solutions are reliable and specifically tailored to each drive system from individual couplings to complete drive line solutions. The transmittable power ranges from 300 W up to 6 MW.
Constant-fill fluid couplings are self-contained drive components mainly used for soft start, torque limitation and dampening of torsional vibrations within the drive line. The different models vary in type and design of volumetric chambers, this determines the startup behavior.
Additionally, Voith also offers fluid couplings with water as the operating medium (type TW). This is critical when operations are located in potentially explosive atmospheres. Furthermore, spheroidal cast iron outer casings (type TU) are available and meet the required material specifications.
Load-free motor run-up Smooth startup of driven machine Overload drive protection Dampens torsional vibration in the drive chain Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects against motor overload Sequential starting of the multi-motors reduces the load on the supply circuit
Additionally, Voith offers fluid couplings with water as the operating medium (type TWV). This is critical when operations are located in potentially explosive atmospheres. Furthermore, spheroidal cast iron outer casings (type TUV) are available and meet the required material specifications.
Load-free motor run-up Smooth startup of driven machine Overload drive protection Dampens torsional vibration in the drive Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects against motor overload Sequential startup of the motors reduces the load on the supply circuit
The type TVV fluid coupling is predominantly used in conveyor drives (e.g., belt conveyors and plate conveyors) and in shredding machine applications. This fluid coupling is also available with two working circuits (type DTVV); the parallel acting circuits double the power transmission.
Furthermore, Voith offers fluid couplings with water as the operating medium (type TWVV). This is critical when operations are located in potentially explosive atmospheres. Furthermore, spheroidal cast iron outer casings (type TUVV) are available and meet relevant material requirements.
Load-free motor run-up Smooth startup of driven machine Overload drive protection Dampens torsional vibration in the drive Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects motor against overload Sequential startup of the motors reduces the load on the supply circuit
Additionally, Voith offers fluid couplings with water as the operating medium (type TWVS). This is critical when operations are located in potentially explosive atmospheres. Furthermore, spheroidal cast iron outer casings (type TUVS) are available and meet the required material specifications.
Load-free motor run-up Smooth startup of driven machine Overload drive chain protection Damps torsional vibration in the drive chain Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects against motor overload Sequential startup of the motors reduces the load on the supply circuit
Additionally, Voith offers fluid couplings with water as the operating medium (type TWVVS). This is critical when operations are located in potentially explosive atmospheres. Furthermore, spheroidal cast iron outer casings (type TUVVS) are available and meet the required material specifications.
Load-free motor run-up Gentle startup of the belt conveyor up to 45s Drive overload protection Dampens torsional vibration in the drive Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects against motor overload Sequential startup of the motors reduces the load on the supply circuit Automatic adjustment to the load condition of the belt through extended torque build-up
Additionally, Voith offers fluid couplings with water as the operating medium (type TWV..F).This is critical when operations are located in potentially explosive atmospheres. Furthermore, spheroidal cast iron outer casings (type TUV..F) are available and meet the required material specifications.
Load-free motor run-up Smooth startup of driven machine Drive overload protection Dampens torsional vibration in the drive Automatic reaction to voltage drops and motor protection Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects against motor overload Sequential startup of the motors reduces the load on the supply circuit
Additionally, Voith offers fluid couplings with water as the operating medium (type TWV..Y). This is critical when operations are located in potentially explosive atmospheres. Furthermore, spheroidal cast iron outer casings (type TUV..Y) are available and meet the required material specifications.
Load-free motor run-up Soft startup with temporally extended torque limitation for longer start-up times Drive overload protection Dampens torsional vibration in the drive Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects motor against overload Sequential startup of the motors reduces the load on the supply circuit
Fill-controlled fluid couplings have an external fluid circuit that is also used for cooling. Additionally, they have a very high thermal capacity, allowing longer and more frequent high load start-up procedures.
The type DTPKL has two axially arranged working circuits that operate in parallel, enabling twice as much power transmission at the same overall height. The variant (D)TPKL-R has a flatter, although longer, tank for lower shaft center line heights. The most compact design is the (D)TPKL-E, which has no oil tank of its own. The tank is situated externally or, e.g., integrated into the swing frame.
Load-free motor run-up Smooth startup of the driven machine up to several minutes Shorter periodic distances for subsequent starts thanks to the stand-still re-cooling Drive overload protection Dampens torsional vibration in the drive Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects motor against overload Sequential startup of the motors reduces the load on the supply circuit
The hydrodynamic coupling circuit is specifically designed for your chain conveyor. The coupling limits the torque in the drive chain to a defined maximum value. This protects the chains and all components against damage. The availability of the armored face conveyor increases and the maintenance costs remain low.
The coupling works with water as a non-combustible and environmentally friendly operating medium. Moreover, water is always available underground. No additional and cost-intensive explosion protection measures are necessary when installing this coupling.
Protection of the drive chain in case of an overload Higher power transmission (up to 60%) compared with similar sized couplings Unlimited start-up attempts following a blocked armored face conveyor Optimally set torque limit for your system Wear-free power transmission; reduced maintenance and repairs
The coupling's hydrodynamic circuit is specially designed for chain conveyors, as it limits the torque in the drivetrain to a fixed value. This protects the chain and all the drive components from damage, thereby increasing the availability and productivity of the armored face conveyor while keeping maintenance costs low.
Furthermore, the coupling operates with water. As a non-combustible and environmentally-friendly operating medium, the coupling requires no additional costly explosion protection measures. Moreover, water is also readily available underground.
Unloaded motor run-up Smooth startup of driven machine Protection of the drive chain in the event of an overload Torsional vibration dampening of the drive chain Unlimited startup attempts following a blocked armored face conveyor Optimally set the torque limit for your system Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects against motor overload Timely, stepped run-up of the motors reduces the load on the supply circuit
The type TP fill-controlled fluid coupling is predominantly used in shredding machine drives. The filling level of the coupling can be controlled, allowing load-free motor run-up and controlling of the torque. Thanks to the hydrodynamic principle, the fluid coupling dampens torsional vibration and torque shocks, thus protecting the drive and increasing the productivity of your system. Due to the active cooling circuit, the TP fluid coupling has a high thermal capacity. This facilitates a smoother startup and acceleration of the driven machine over a longer period of time. Additionally, this fluid coupling is available with two axially arranged working circuits (type DTP); these parallel acting circuits double the power transmission. For type TPW, the operating medium is water, which makes this coupling especially suitable for use in potentially explosive atmospheres.
Load-free motor run-up Smooth startup of driven machine Protects the drive in case of an overload Dampens torsional vibration in the drive Accelerates heavy masses Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work Automatic load sharing in multi-motor drives protects against motor overload Sequential startup of the motors reduces the load on the supply circuit
Load-free engine run-up Smooth startup of the driven machine Drive component overload protection Damps torsional vibration in the drive Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work
Reduced load engine run-up Smooth startup of driven machine Drive component overload protection Dampens torsional vibration in the drive Protects system components, thereby increasing service life Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work
When completely emptied, the torque transmission of the fluid coupling from the engine through to the driven machine is de-coupled (hydrodynamic clutching function). Thanks to the hydrodynamic principle, the fluid coupling dampens the torsional vibration and protects the drive chain against overload, which increases the productivity of your equipment.
Load-free start and idle speed operation Smooth startup of driven machine Drive overload protection Dampens torsional vibration in the drive chain Protects system components, thereby increasing service life Accelerates heavy masses with high break-away torque Hydrodynamic switching function Allows stored energy in the rotors to be released during surge loads Robust and unsusceptible to environmental influences Wear-free power transmission; less maintenance and repair work
Design of complete drives Dimensioning of couplings for the optimal performance of your system Analysis and optimization of the operating state of drives in existing systems (retrofit) Advice about the selection of optimal start-up technologies Competence in systems for all mining equipment and the bulk material industry
Were going to do a quick intro to pXRF and pXRD principles and how they work. Then, were going to focus on pXRF, and work through the products, some of the suggested operating procedures, and then spend a bit of time looking at good references, case studies, and applications.
Were have complete geoscience solution; we have diffraction, which can gives us quantitative minerology. So if were looking at this slide, on the top left we can actually derive the amount of minerals so they can quantify them. We have X-ray fluorescence, which is chemistry. We get very good, almost lab grade results if were doing the right job. And then, we also have the ability to look at structural properties of geo sites as well through microscopy, or optical minerology, or petrology, which is again, the backbone of what we learn at university when were looking at minerology. Its the gold standard in a lot of ways.
Breaking it down to the products. And again, today were just going to focus on the portable products. This is our XRF products. Again, chemistry. We have the new VANTA Series handheld, which Ill explain a little bit in the next section. We have the DELTA, which has been the workforce for a good six or seven years now. Many people are familiar with our DELTA Series handheld. And then, Im just going to mention we have some portable bench-tops, some sort of customized smaller systems, as well as our process, and online, and sorting systems as well. If youd like more information about the other products, feel free to get in contact with us after the webinar.
And the one slide which Ive got for microscopy is that we have a bunch of solutions from stereo microscopes to the polarizing microscopes and the metallurgical microscopes, which are all around optical mineralogy. Again, if you need more information, we can point you to the product managers and the specialists in the microscope business.
With XRF and XRD, as you wouldve read in the webinar intro, this talk is essentially targeting people whove got an existent background in the physics. So, Ill keep it quite simple. But again, if you need more information about how the fundamentals work, we can provide you with that. X-ray fluorescence, we shot an X-ray on the sample, we use a technique called EDS, so its Energy Dispersive XRF, where were basically able to get characteristic X-ray back for each element. We measure them in a spectre, we quantify them, and thats what we use to get a quantitative result for each element. Diffractions collect different. Were basically getting the shinning and x-Ray on a sample, were looking at diffraction of the mineral layers within each compound. Theyre all crystal structure. And we end with a diagnostic fingerprint for each mineral. And then, again, we can quantify that using processing techniques.
Many of you know the periodic table continues to give better coverage and better sensitivity. Weve looked at this many times over the years. And essentially, what were looking at in the grain is elements that we can get down to low PPM levels. So with modern X-Ray tubes and with silicon drift detectors, we can now do a really good job across pretty much the whole periodic table. And especially the light elements. The new systems give us the ability to things like magnesium, aluminum, silicon, to labels that weve not been able to do before.
And if we start to look at the market now, we play work different parts of industry. We call it the Mining Value Chain. We start with geoscience research, with geological surveys, we then move to mineral exploration, where were developing around existing operations. We then move into the grade control area where weve got systems trying to make real-time decisions around materials and destination of materials. From there, were able to use that to form the processing division of the business around geometallurgy and aspects of decision-making on chemistry and minerology. And then, at the very backend of the business, we can also play a role in mine closure, and in the environmental business around looking at solar irradiation and contaminated land. Theres one separate business, which we have a nice sort of segue way into, which is around maintenance. A lot of our tools we use for NDT, and for Alloy, and PMI, and things like oil. And again, if youd like more information on that, which Im not going to cover today, we can point you in the right direction.
To dial it down a little bit, and to focus on XRF in particular and this is where Id like to just quickly talk about our new offering. In September, weve released our fifth generation handheld called VANTA. Its a complete revolution in the industry. Its ten plus years of, basically, building an instrument thats been specifically designed for our market. And when I say that, the core pillars are around ruggedization. So we now have IP67 rating, dust and water proof, we have very high temperature ratings, up to 50 degrees C for geocycle. And one of the cool things that will detect a shadow, the mechanical eye lid that come down and protect the detector. We also revolutionary XRF technology, which is all about better accuracy, better precision, and higher cap rates, which means we can do more work faster, with higher accuracy and higher precision. And in the productivity space, we have a whole bunch of new cool stuff coming around cloud-enabled data processing, we have things like embedded GPS, new software its a revolution in handheld XRF.
The products aside, where weve really established ourselves as, essentially, the industry leaders is We all know that XRF can do a great job, but theres a bunch of things that we need to do. And its very similar to what the lab has to do when they process our samples, its all around best practice. We put out a blog, and we had a week called Geoscience Week where we put out a guide called A Quickstart Guide for Best Practices in Portable XRF.
So, we look at the start. We need to start with designing an orientation survey. A lot of that is around standard operating procedure, chain of custody, QA/QC, all things that as geologists were very comfortable dealing with our normal lab regime. This paper that was published and I was a co-publisher, it was a cornerstone paper, which goes to each one of these procedures, around each part of the procedure. Selecting a sample. Preparation what do we want to look at around sample preparation? Data handling, data custody. And then, what do we actually want to do with the data when were finished.
And the next slide is all about selecting what sample. What are we working with? Are we working with bio-geochemical samples? Are we working with soils? Are we working around a drill rig where were taking precaution, or where we actually want to look at drill quill? So, we have to make a decision about the way were going to analyze that sample, and then move forward with the process.
And this slide encompasses a few of the really key aspects. Probably the main one, in the top right corner, is grainsize. And we know that if we have homogenous good materials, were going to get a good result. But if were analyzing course grain materials, were going to get very erratic and heterogeneous results. Similarly, if were running through bags, were going to get attenuation thats obviously going to affect the calibration, its going to dilute our results. So were able to do that, but we need to make sure sap specific calibration is built up to take care of all of those things. And on the left, its an example of how to actually select the right type of soil to get out a sample. Were looking at a soil horizon here, with different parts of the stratigraphy to leave different types of metal due to things like redox and chemical reactions going on in the ground itself. Were actually able to use portable XRF to tell us what sample has the accumulation of metals, and which sample is going to get us the best results.
As the manufacturer, we do the best job we can to give you guys a robust calibration out of the box. We do have lots of different standards, and lots of different samples, but at the end of the day, you want to make sure that youll qualify an instrument, and youre doing the right thing around looking at the performance of the XRF versus certified reference materials. Theres an example of a company, very well-known with research in Australia, who have very good standards that we can after. And this shows portable XRF versus them. Its iron, in this particular case. And if were doing the right thing, we get the same result. So, its very encouraging.
And this is XRF instrument which you can go and buy off the shelf. Theres some pricing there. This is the packaging. You get a nice little portable XRF standards package you can take out into the field for any sampling regime.
The next step in the process that were really very comfortable and very used to doing, is coming on site, and developing site-specific standards. Were working with site-specific standards because the final refinement, or the final tuning or tweaking call it what you will is actually tailoring the XRF to do the absolute perfect job for the type of rocks that youre working with. And what we can see in the bottom left hand corner here is a set of 45 or 47 samples for a very low range metal. In this particular example, its copper and iron in an IOCG deposit. And we built a calibration, and basically, tweaked the calibration so wed get a one to one rating and a 99% correlation to make sure that youre very confident that the analyzer is doing the right job.
As I mentioned earlier, one of the critical points with portable XRF is around sample presentation. And again, we have a whole lot of solutions and a whole lot of expertise around providing that guidance, and providing recommendations on what sort of tools and equipment we can use in the field. Again, if youd like more information, we can certainly point you into the right direction with some of these companies, whether itd be drilling a hole in a sample, or taking a sample right through lead-based, you know, a ring mill or a jewel crusher to get 95% of your sample passing 75 micron. The more that we get towards that, the better results we can achieve in the field.
And if we just want to spend a few seconds focusing just of field-based sampling solutions, theres some fairly well-known bits of equipment out there which you can go and purchase, including this rock grinder for sample either across a wall or a phase underground, or theres this small hammer mill up on the right hand side, which we can use for crushing things like RC chips or soil thats not quite homogenous enough in the field. And you can take these out in the field, run them off 12 volt system off a car. And you can quite easily obtain lab grade results in the field.
And then, more of the Complete Solution level. We have a company that we work in tandem with around creating and developing a full solution. And thats crushing and grinding. We have a sample press. A sample press enables to create a puck without a consumable, it doesnt require a window, which means that youre getting a lot better XRF performance without having attenuation. They also have systems, which flows in the laboratory. Its a laboratory information management system, which manages the chain of custody, the standards, it merges the real-time QA/QC actually while youre running the sample. So, it gives you confidence that youre getting good results whilst youre actually running the samples.
And a key part of what were dealing with is how do we deliver our data in real-time. And anybody who uses the portable XRF knows that we can generate a lot of data very, very quickly. Weve got spreadsheets of multi-element data arriving all over the place. I quite often see people with laptops where theyve got 20 or 30 spreadsheets altogether on the one page, and it gets quite difficult. But having solutions, like this one Ive got up on the screen, the data can arrive into a real-time web portal, it can be QA/QC validated, it can be managed remotely, and then we can get an output, which is designed to be doing exactly what the client would like to see. Roll out of bed in the morning before they go and see the drill rig, and they can see the data on their iPhone, and say, Oh, look, were drilled through the contact, now we need to stop the drill, and make that decision, save lots of money, and then move the drills to the next site. Its all about real-time decision-making.
And then, once we have all that data, its what do we do with it. And as geologists, we generally pass that into a 3D model, we use that 3D model for a lot of things, we use it for mine design, we use it for vectoring towards mineralization, were targeting where were going to drill next. And we have tools, where we have our portable XRF data arrive into a classification system, as in the right hand corner there. The rocks get classified, and then passed straight into a 3D model. So its all about expediting the chain of custody of the data that usually can take months, even up to half a year to get this data into a model and start working with it.
And then, the one small part Im going to talk about a little bit is about how we take that data, and how do we report that data to the market. And again, its been quite controversial in the past, myself and a few others involved around pXRF technologies spent some time with this and said, Well, lets include some of these sampling techniques, some of the recommended procedures when people want to report the data so they can go to table one, we can get some information, and we can get some recommendations on what we need to do to report it. Again, for those whod like more information, weve got lots of good examples with companies who do this the right way, and what you should be looking at to put out in the market.
One of the very well-known industry initiatives that happened a couple of years ago, up here, in Canada, ran by a very well-known geochemist, where we had a bunch of industry companies who sponsored, and we worked through the quality control and assessment of portable XRF. It was all about bench marking. What can XRF do? How can we develop standard operating procedures on variable media? And how can we recommend the best use? Again, thats a great reference, its about 500 pages of reports and data there. And you can go to the its actually on the Association of Applied Geochemists website and download the report. Its a great reference.
And as part of that work, an editor of Geo Magazine, we put together a thematic set. So, two complete issues of Geo which were completely dedicated to portable XRF. And that was where companies and institutions submitted papers on best practices and what theyve done. So, its a great reference out there for those who are looking for papers and for direction on where to head.
An example in Finland, was put together in a special report, which has a whole chapter on portable XRF. And for this particular example, it was looking at Geo chemistry, and how theyre effectively using portable XRF to do that. And in light of that, and actually many years ago, about 15 years ago this is an example of geological survey of Canada with using a similar technique, theyre using litho-geochemistry, so using the chemistry to tell us what part of the stratigraphy and what rock types are in. And what were looking at here, on this downhole plot is the blue data is ICP thats lab data and the red data is XRF, and were getting very agreeable results between the two datasets. And from there, theyre able to work out the rock type, determine the stratigraphy, and basically, adapt and design their drill program in real-time.
Moving forward, an organization that weve worked with a lot in Australia, kind of the coalface and the cutting edge of pXRF technology is that we know the data is very, very good. And when we look at these plots, we can see extremely good agreement between elements. In geoscience, we use certain elements to tell us certain things. We use arsenic as a very string proxy for gold mineralization, we use things like titanium, zirconium, and chrome. They are mobile to mobile element ratios to tell us what are rock types are. And if take that dotted board, were actually able to use that to start to predict and work out what rock types are, and take the subjectivity and some of the fuzziness out of logging rocks. And what were looking at here, its an advanced algorithm its actually called wavelet tessellation where were using iron through a project that was developed through a group which was a large research initiative in Australia. And we can use iron through a wave of tessellation to, basically, break out the rocks and start to break it down into different scales of features that were seeing, you know, first order versus second order versus third order features, and to help that and assist us in breaking up the rock types, which may not be visually obvious for people to pick out in the field.
Moving from the R&D and the geo survey applications, its the first place that we tested XRF and our businesses, generally around soil sampling. So soil sampling works very, very well if fine-grained samples are able to move about on the surface of the earth. And that geochemistry very, very rapidly. And in this particular example, we managed to cover this area, and basically, build up a real-time geochemical map very rapidly. From there, we could move around, we could decide where were we going to go next, and we can use that as a decision-making tool on how were going to change our sample program on the site. One of the really cool things about having assay data right from the field is that you dont just get one element. In the last example we were just saying copper, but now, in this particular example, which is the same dataset, we can see every element side by side. So we have copper, lead, zinc, and we get to see the way the different metals are moving around in the system, and we can see whats mobile and whats not. We can see contamination overprint. For working in an area around the mine, we can see where theres sulfur and sulphides that have been delivered around roads and things like that.
And if we start to talk about the return on investment, and what we ca actually get out of portable XRF, well, the value proposition, the current example I have up on the screen was one of the users in Australia, and it shows what can be achieved with one month with one instrument. And in this particular example, they were able to go out and do very detailed, very fine geochemical sampling over a known area of mineralization its South Australia, around the Burra Copper deposits, which is one of the biggest copper deposits in the world and delineate exactly where they were going to go and drill next. And again, this is several years ago as the technology was emerging. It got the company into the place that they needed to to make those decisions.
As we go further down the value chain, once we have an anomaly, once we have a target, the first thing were going to do is start drilling it. And some of the early drill procedures we might use XRF. In this particular example, were using auger drilling in West Africa. We can see the samples are being brought into a bench-top system. Weve got a small little XRF added in the hood. The samples are being run in a very good chain of custody with great validation. And then, were using that data to classify the rock types, because in that area we cant actually tell what the geology is. Were in an area of residual surface. In this example, we can actually map out the grainstone built amongst the sediments, and then we know where to go and target, because were looking for orogenic gold. So its a very, very powerful tool for delimitating the stratigraphy through what would usually be very difficult to look at.
And sticking on the gold theme, the next example I have up on the screen gives us an example of what the geochemical signatures and what the common pathfinders are that were going to use for going out and looking for gold. And one of the things that Ill state up front and we have for many years is that portable XRF is not very good for gold, but theres a whole host of elements which we can use to go and look for gold, which we call pathfinders. And in this example, at the top here, we can see one of those elements, with ICP versus the same element with portable XRF. And were getting exactly the same map, which means that were very confident that portable XRF is doing the same job.
A little bit of a gold theme here. And thats because the gold business, to us, has been a very effective place where weve, obviously, put a lot of instruments into. And its also an application, weve developed a lot of tools and techniques. This particular paper which I have now on the screen was an example several years ago. A fellow who put together a program at Plutonic Gold Mine to, basically, define stratigraphy and use it for geometallurgical work, which were going to have a look in a couple of slides on the next page.
He was able to, basically, reconstruct the stratigraphic model around Plutonic. Basically, its a sequence of bath salts where the bath salts flow in the basis, so in-between flows the gold deposits along those surfaces and substrates, which in the top corner, the red circles, were looking at chrome versus gold. So, as we step down the stratigraphy, the gold accumulates on the stratigraphic boundaries. Now, when theyre able to do 3D surfaces of that, where they can actually model that, and then use that as a tool for vectoring and for modeling where they think the next gold occurrence is going to be, or look for extensions of the orebody. He was also able to take that data and domain it out in a deposit thats quite difficult. Its a refractory gold deposit, its got high arsenic, its got free milling gold versus refractory gold. Essentially, as the arsenic grade goes up, the recovery drops. So what they were able to do was blend and change the process and technologies so they could optimize recovery based on the material that was being delivered to the mill. And again, its an excellent example of having a dataset which they didnt have the past to drive better recoveries, and to get better results in the mill.
The other cool things weve added in the last few years is the camera and collimator feature. And what they give you the ability to do is actually use the XRF with a focusing mechanism. So, with using the camera, we can collimate down so we can change the size of the zoom to look at a bit smaller things. We can actually use that microstructural assessment. Were looking at grain particular or phase particular work. We have some gold grains in those particular examples, which would be quite difficult to observe by the eye, but with an XRF and a camera, we can do a great job.
Moving on to grade control now, we have an example here of iron ore in Australia where our neo systems have the ability to take something that amounts to a 90-second test, and do it within 15 seconds. So what weve got here is iron, essentially in 90 seconds versus 15 seconds, and against Silicon. This is an example where a lot of elements perform extremely well. And its hard to believe even for myself that we can deliver such good data in such rapid time, which means that you can put a lot of samples through that you may not have been able before, and you can make decisions much faster than youve ever been able to before.
On the second slide, were looking at aluminum and phosphorus. In looking at the deleterious settlements in iron ores. So the last example I have here, its a very hot topic at the moment, the whole lithium factories business is, obviously, very energized at the moment pardon my pun. And its technique where we can actually use portable XRF and XRD together. Because if were looking for lithium, theres a bunch of very cool elements in the periodic table, one being rubidium. It fractions into lithium within the same sort of ratios that we see in lithium. And the other thing that we need to do is look at the minerology. So, we might have a lithium deposit, but it doesnt necessarily mean we can mine it. The XRD is a fantastic tool. Were looking at what phase is it in, were looking at if its spodumene, or if its petalite.
Its been one of the applications weve had a lot of success with. And for those geologists that have worked particularly in various gold deposits, its the hydrothermal fluids, I mean particularly orogenic and epithermal or high solvation systems. They generally have different elements that come along with them. Arsenic is probably the silver bullet. We get very strong association in some orebodies obviously, not all where we can use arsenic in a ratio to give us a ballpark relatively, not always absolute of the gold grade. We have many examples, and many published examples that show how well that can work.
What is X-ray fluorescence and what is XRF? XRF is X-ray fluorescence; thats what it stands for and its a method to get fast, non-destructive elemental information about the sample that you have in front of the analyzer.
What type of samples or applications would you be using XRF? The most common application is for scrap sorting. A scrap dealer gets more money if he knows that his stuff is all the same thing. So when they go to melt it off, they can make new stuff out of that. So, thats really what we do as we say okay, its this grade of metal or that particular grade of metal. And they can sort it into light piles and sell it for more money, and so thats where the value gets added, by knowing what you have.
What other type of applications is XRF being used for? Theres some other metal applications which are for positive material identification which are in oil refineries. You need to know that the pipes that you install there are what theyre supposed to be, so they dont corrode too fast and leak and create a health hazard. But theres a lot more than just metals it can go on to soils for mining or for environmental, if youre looking at like lead in soil and a number of other things like that. Theres consumer products looking to make sure about lead in toys, its even used in archaeometry to look at what paintings are made of, because its non-destructive you can use it on pretty much anything.
Do you have to be highly trained to understand how to use this equipment? No, all the difficult mathematics and all that stuff goes on kind of behind the scenes, so weve made it pretty straightforward to use. With a quick safety training in most regions of the world you can be up and running in a couple of minutes.
Are there any other alternatives to XRF? XRF has kind of a unique space in that it gives you quick answers out in the field because you can take the portable instruments out to your sample. And there are a bunch of laboratory techniques that can be a lot more precise, but those usually involve bringing the sample back to the lab, they require like a lot of digestion and work and sample preparation in the lab, and they also destroy a little bit of the sample. So they have some limitations. Some people would send things into a lab, youre doing this more on location.
How long does it take to do a sample? That really depends on what kind of answer you want to get. For a lot of the scrap sorting, we can get an answer in a second or two in terms of what type of metal it is. Some of the metals are more challenging, it might take 15-20 seconds. In the mining kind of space, theyre looking for usually some very detailed information and the test can take a minute or two. But its again relatively quick compared to the hours of digestion you might have to do in the lab or when you send it off to a lab out, waiting for them to get to it. If you expedite it and pay the extra fees, cause youve got that much time in transit time alone sending it off to a lab. So the immediacy of XRF is really one of the big selling points for it.
All XRF instruments are designed around two major components: a X-ray source, commonly an X-ray tube and a detector. Primary X-rays are generated by the source and directed at the sample surface sometimes passing through a filter to modify the X-ray beam.
When the beam hits the atoms in the sample, they react by generating secondary X-rays that are collected and processed by a detector. Now, lets look at what happens to the atoms in the sample during the analysis. A stable atom is made out of a nucleus and electrons orbiting it. The electrons are arranged in energy levels or shells, and different energy levels can hold different numbers of electrons.
When the high energy primary X-ray collides with an atom, it disturbs its equilibrium. An electron is ejected from a low-energy level and a vacancy is created, making the atom instable. To restore stability, an electron from a higher energy level falls into this vacancy. The excess energy released as the electron moves between the two levels is emitted in the form of a secondary X-ray. The energy of the emitted X-ray is characteristic of the element.
This means that XRF provides qualitative information about the sample measured. However, XRF is also a quantitative technique. The X-rays emitted by the atoms in the sample are collected by a detector and processed in the analyzer to generate a spectrum, showing the X-rays intensity peaks versus their energy. As we have seen, the peak energy identifies the element. Its peak area or intensity gives an indication of its amount in the sample.
The analyzer then uses this information to calculate a samples elemental composition. The whole process from pressing the Start button or trigger, to getting the analysis results can be as quick as two seconds, or it can take several minutes.
Compared to other analytical techniques, XRF has many advantages. Its fast, it measures a wide range of elements and concentrations in many different types of materials, its non-destructive and requires no or very little sample preparation and its very low-cost compared to other techniques. Thats why so many people around the world are using XRF on a daily basis to analyze materials. If you want to find out more about our range of XRF analyzers, please visit our website.
Gold, silver, platinum and their alloys, the gold XRF analyzer can measure them all. The gold analyzer quickly and accurately determines the karatage of gold items, the purity of silver items and any other metals that are in the piece. The gold analyzer was designed with the jewelry industry in mind. Its small footprint wont take up valuable counter space and it can test any piece of jewelry in seconds.
Testing couldnt be easier. Just place, close and tap. The gold XRF analyzer is safe for any user. It can only test samples when the lid is shut, and the flashing light on the top lets you know when the test is actually taking place. Compact, accurate, fast.
Gold XRF testing is completely nondestructive. The sample is not affected or harmed in any way. The gold analyzers viewing window and well-lit chamber allows both operator and customer to see the sample as it is being analyzed.
Karat Mode or the more comprehensive Chemistry Analysis Mode can be selected. The gold analyzer uses X-ray fluorescence, a nondestructive and fast analytical method to test samples. Its easy to use and adapts to nearly any sample size or shape. An integrated camera allows the gold analyzer to focus on and get results from individual components. This is useful when testing pieces that include gemstones.
The gold XRF analyzer offers the convenience of portability as well. An optional battery pack allows testing on the go. The gold analyzer weight only 22 pounds, about 10kg and combined with its custom carrying case can go anywhere you need it to.
Selecting a successful maintenance strategy requires a good knowledge of maintenance management principles and practices as well as knowledge of specific facility performance. There is no one correct formula for maintenance strategy selection and, more often than not, the selection process involves a mix of different maintenance strategies to suit the specific facility performance and conditions.
There are a number of maintenance strategies available today that have been tried and tested throughout the years. These strategies range from optimization of existing maintenance routines to eliminating the root causes of failures altogether, to minimize maintenance requirements. Ultimately, the focus should be on improving equipment reliability while reducing cost of ownership.
An effective maintenance strategy is concerned with maximizing equipment uptime and facility performance while balancing the associated resources expended and ultimately the cost. We need to ensure that we are getting sufficient return on our investment.
Are we satisfied with the maintenance cost expended versus equipment performance and uptime? There is a balance to be had in terms of maintenance cost and facility performance. We can develop a suitable maintenance strategy to help tailor this balancing act in order to ensure the return on investment is acceptable (Figure5.11).
A maintenance strategy should be tailored specifically to meet the individual needs of a facility. The strategy is effectively dynamic and must be updated periodically as circumstances change. The strategy must include a detailed assessment of the current situation at the facility and consider the following questions:
Once we have clarity on the current situation and constraints, we need to define the objectives of the maintenance plan. The objectives must align with the business objectives of the company. They must be developed by all of the key facility stakeholders and be clear, concise and realistic. There may be a number of components to the strategy objectives for example: improve equipment uptime, reduce maintenance costs, reduce equipment operating costs, extend equipment life, reduce spare parts inventory, improve MTTR, etc
An example of a maintenance strategy workflow is illustrated in Figure5.12. This workflow is developed to optimize and improve an existing facility maintenance program. Depending on the specific circumstances at the facility, our strategy may also take us into the direction of a step change approach to maintenance management and opt for a reliability-centered maintenance (RCM) program, which may replace our existing maintenance program. This strategy is labor and time intensive and can be expensive; we will discuss RCM in section 5.7.1.
It is a common theme in the industry that maintenance budget and resources are very thin on the ground relative to the amount of work that needs to be done. Therefore, prioritization of maintenance resources is absolutely essential in order to be successful. Once we have defined our maintenance strategy objectives, we need to define facility equipment criticality. We have discussed the concept of criticality in Chapter4. Criticality is a risk-based approach that can help us to prioritize our resources effectively. It can also help to appraise the requirement and effectiveness of maintenance tasks already populated in the MMS or CMMS.
Another common theme in the industry is that many computer maintenance management systems are populated with a large proportion of preventive maintenance tasks that may be considered as superfluous and even not necessary. These tasks may consume a large proportion of the maintenance resources and time without an acceptable return on the investment made (maintenance cost). The maintenance strategy should also ensure the current data in the CMMS is value adding and therefore carry out a cleansing exercise. A data cleansing exercise critically reviews and appraises the current CMMS tasks and aims to eliminate the tasks that may not be adding value and therefore are superfluous. By focusing on equipment criticality, these activities can be reviewed and appraised in a logical and systematic way.
Once the equipment criticality assessment is completed and the strategy objectives have been reviewed and updated, maintenance resources can then be aligned to the strategy. The maintenance strategy objectives will dictate the resources and associated maintenance costs. The next step in the strategy development process is to update the equipment maintenance and operating plan as presented in section 5.5. The EMOP is the primary record and source of maintenance and operation information of each equipment item and includes the up-to-date maintenance and operating strategies. It provides the baseline information including equipment maintenance and operating parameters. We are then in a position to implement the maintenance strategy on the facility.
It is important to understand the impact (and the success) of the new maintenance strategy. This is achieved by setting key performance indicators (KPIs) to assess the facility maintenance performance. This is done by first developing a benchmark data set. How is the facility currently performing? What is the cost of maintenance? What is the MTBF? What is the MTTR? What is the maintenance rework ratio? Once the current facility maintenance performance is benchmarked, we can then measure maintenance performance against this benchmark. Maintenance performance is reviewed periodically and, depending on the results, may be reviewed and updated more frequently. We will look at facility integrity KPIs and dashboards in Chapter9.
If the maintenance performance is in line with business objectives, then the facility operation will continue; however, if there is any deviation in performance or change in the facility process or criticality ranking, then the maintenance strategy should be revisited.
In 1978 Stanley Nowlan and Howard F. Heap published a report aimed at determining new and more cost-effective ways of maintaining complex systems in the aviation industry. It was called Reliability-Centered Maintenance (RCM) [5.2].
Today, reliability-centered maintenance (RCM) is used across many industries and is recognized as one of the leading practices for oil and gas and petrochemical facility maintenance. RCM acknowledges that all equipment in a facility does not have an equal importance and that there are significant advantages in prioritizing maintenance efforts on certain facility equipment. RCM effectively provides a structured approach to the development of a maintenance program. It focuses on equipment needs and ultimately results in a well-grounded basis for facility maintenance with a high proportion of proactive maintenance. RCM addresses the basic causes of equipment and system failures. It aims to ensure that controls are in place to predict, prevent or mitigate these functional failures and hence the associated business impact [5.3]. RCM is defined by a technical standard from the Society of Automotive and Aerospace Engineers (SAE), namely SAE JA1011 (1999) [5.4].
Reliability-centered maintenance (RCM) analysis provides a structured framework for analyzing the functions and potential failures of facility equipment, such as pumps, compressors, a facility processing unit, etc. The emphasis of the analysis is to preserve system function, instead of focusing on preserving the actual equipment. The output of an RCM program is a series of scheduled maintenance plans. The RCM standard, SAE JA1011, describes the minimum criteria that a process must comply with to qualify as an RCM Process [5.4].
First the RCM team should be carefully assembled. The team should comprise a cross-section of facility operations, maintenance and FI&R teams with a strong technical understanding of the equipment to be analyzed. The team should also be conversant with the RCM analysis methodology.
RCM analysis requires a large investment of time and resources. Given this, it is often necessary for the facility maintenance group conducting the analysis to focus on a selection of equipment or systems. The equipment or systems to be analyzed should be identified and boundaries drawn around the battery limits of systems. This is to ensure clear demarcation of the RCM scope so that efforts and time are directed appropriately. It is often the case that a criticality assessment is used to determine the equipment or systems selection.
Reliability-centered maintenance focuses on preserving equipment functionality. The next step in the process is to determine the function or functions that the equipment or systems are intended to perform. Equipment functions should also be prescriptive in the definition of a function and include performance limits, for example.
Once the functions are clearly defined by the RCM team, their corresponding potential functional failures are defined. Functional failures may also include poor performance of a function or overperformance of a function as well.
The next step in the process is to identify and evaluate the effects of the equipment failure. This step enables the RCM team to prioritize and choose an appropriate maintenance strategy that can tackle the failure. It is common to employ a logic diagram to structure this part of the process in order to consistently evaluate and categorize the effects of failure.
It is important to leverage the skills and experience of the RCM team in order to ensure the cause of the failure is clear and accurate. The cause of the failure should be described in sufficient detail at this stage. This is so that we are able to ensure the maintenance task selection step in the process is confidently and reliably completed. It may be appropriate to refer to the RCM standard, SAE JA1012, which presents useful guidance as to how to identify causes of failure [5.4].
At this stage in the process, we have identified the functions that equipment is intended to perform and the ways that these functions could fail. We have evaluated the effects of functional failures and identified their causes; the next step in the RCM process is to select appropriate maintenance tasks for the equipment to prevent such failures. There are a number of ways to carry out this exercise; however, the RCM teams skill set and knowledge is the key factor.
The final step in the RCM process is to package the maintenance tasks into a practical and robust maintenance program. This process involves reviewing the selected maintenance tasks and grouping them in a logical way so that they can be uploaded into the facility CMMS. The ultimate goal in packaging the RCM tasks is to arrive at a practical and efficient maintenance program.
Reliability-centered maintenance (RCM) has been in use for a number of years. It provides a structured and systematic framework which can result in an effective maintenance management program for facility equipment.
It is no surprise that RCM is a resource intensive and time-consuming process that can be expensive to develop and implement. There are a number of iterations of RCM that attempt to reduce the effort needed to develop and implement an RCM program, with varying degrees of success. It is important to maintain the key principles of RCM and not to overstretch the battery limits that were agreed on by the facility maintenance team at the start of the process. This may lead to disillusionment and frustration and eventually may result in a failed implementation effort.
The approach to the development and implementation of an RCM maintenance program must be executed with dedication and tenacity. It is also important for the facility management team and the wider facility functional groups to buy in and support the RCM implementation effort.
Failure mode and effects analysis (FMEA) is a useful and practical tool for analysis of equipment failures. FMEA, which dates back to the 1940s, was one of the first techniques used as a methodical approach to failure analysis.
It was initially developed by the US military to address problems with the premature failure of military equipment and systems. It is detailed in MIL-P-1629, which is a US Armed Forces Military Procedure [5.5]. FMEA has evolved over the years and is now extensively used across a number of industries including space agencies, food service, software, healthcare, petrochemical and oil and gas. FMEA may also be referred to in standard SAE J1739 (Potential Failure Mode and Effects Analysis in Design) [5.6] and standard IEC 60812 (International Standard on Fault Mode and Effects Analysis) [5.7]
FMEA can also form part of a reliability program such as an RCM study. It involves reviewing equipment systems, subsystems and components to identify failure modes, their causes and their effects. The effects analysis involves examining the consequences of the failures on the particular equipment systems, subsystems or components. For each subsystem or component the failure modes and their resulting effects are recorded in an FMEA worksheet. There are many variations of FMEA worksheets to record the output of the analysis.
FMEA studies are particularly useful when applied to specific equipment or systems. This is because the tool is designed originally for standalone military equipment. We may also wish to target the FMEA study on specific equipment or systems may have been highlighted as the result of a criticality analysis.
Planned maintenance optimization (PMO) is a well-established, tried and tested maintenance strategy, dating back to the 1990s. Around this time there was a lot of concern from the industry that RCM did not suit the requirements for facilities that had existing maintenance programs with limited resources and timescales to perform an RCM study. This is because primarily RCM is a tool that is designed for use in the design stage of the facility life cycle. PMO, on the other hand, is specifically designed to target existing maintenance programs.
The PMO process is illustrated in the workflow in Figure5.14. PMO identifies planned maintenance database activities from an existing facility CMMS, categorizing them into planned maintenance craft groups. The workflow then reviews each corresponding facility equipment history to determine if the planned maintenance task is necessary. These tasks are critically evaluated and ultimately optimized based on the added value. Finally the maintenance program is updated along with the CMMS.
A PMO study may be conducted manually in a task force team or by employing commercially available software. There are numerous PMO software titles available in the market, some of which can be interfaced with a CMMS. Typically the decision to implement a PMO strategy is made in an ad hoc fashion by the maintenance management team. It is usually driven by budget and resource constraints.
Equipment failures are a result of defects; therefore by eliminating defects we can improve equipment reliability. Defect elimination is a maintenance strategy that takes us back to design. It aims to prevent defects being introduced at the early stages of the equipment life cycle, thereby removing the defects during the operational stage of the equipment life cycle.
By eliminating the defects that have potential to cause future equipment failures, maintenance requirements will also be reduced, resulting in improved equipment uptime. Defect elimination can actually reduce the maintenance requirements on equipment or systems and hence lower maintenance cost.
Defect elimination aims to identify failure modes and eliminate them at the outset. Each part of the equipment is taken in its component parts and corresponding defects are identified. Mitigation plans are then prepared for each and every defect identified in order to eliminate the failure mode. Control measures and quality assurance standards are developed in order to detect and eliminate defects before they are designed into the equipment and systems. One of the methods that could be employed in defect elimination is the FMEA tool as presented in section 5.7.2, which is based on failure mode and effects analysis.
In some instances maintenance managers may decide to purposefully overdesign a particular equipment or system on the facility. The idea behind this is that these particular equipment items or systems are therefore able to withstand deterioration processes more and function for longer periods of time between failures.
This decision may be made when dealing with highly critical processes on the facility, such as processing toxic or hazardous materials or chemicals, or where there is a requirement to increase the reliability of a certain part of a process that may warrant additional robustness of equipment design.
This is a strategic maintenance decision intended to prolong facility equipment and systems life and therefore maintain longer periods of production. It involves increasing the design specification of equipment or systems with more robust parts, higher specification materials of construction, better surface protection coatings, etc.
Maintenance management is a continuous improvement process. The intention is to add value by improving equipment reliability while reducing cost of ownership. Clearly there is a balance to be had with cost of ownership versus additional value added, particularly with this strategy. There may be a higher cost of ownership; however, this is offset against the improvements to the production output.
Such work is typically done as an overhaul, where the whole of the equipment is removed from operation during a shutdown and taken to the workshop to be stripped down to its component parts and rebuilt as new.
Use of shutdown overhaul maintenance strategy is aimed at ensuring uninterrupted production for a specific period of time. By renewing or overhauling equipment regularly we remove the wear-out related stoppages. Once equipment is overhauled to manufacturers standards we can expect as-new performance. However, we are also exposed to infant mortality risks due to poor quality control, mistakes during assembly, incorrect material selection and introduced damage.
Maintenance can be considered as the replacement or repair of components and assemblies (before or after failure), so that the unit concerned can perform its designated function over its expected life.
Formulating the best life plan (see Figure4.10) for each unit. This is a comprehensive program of maintenance procedures repair/replace/inspect at various frequencies spanning the expected life of the unit.
Formulating a maintenance schedule for the plant (see Figure4.11). This should be assembled from the programs of work contained in the unit life plan(s) but should be dynamic, e.g. readily adjustable in the light of changes in the production schedule.
Establishing the organization to enable the scheduled, and other, maintenance work to be resourced (see Figure4.12, which also shows that maintenance strategy and capital replacement policy are interrelated, i.e. maintenance cost influences unit replacement decisions and vice versa).
R4.1With industrial plant the physical assets have a fixed location and are connected together via a batch or process arrangement to perform the overall plant function. The function is to provide a manufactured product to a market. The objective is to maximize long-term profitability. The best way of modeling such operations is by process flow diagrams down to the unit level of plant supplemented as necessary by systems diagrams for the services.With an open cast coal mining operation the physical assets are spread over a wide geographic area and can be divided into mining assets, conveying/transport assets and coal preparation assets. The mining/transportation assets are mobile. The function of the operation is to provide mined coal to a market. The operation can be modeled using a combination of modified process flow diagrams (see Figure 1 in Case study 5 of Chapter 12) and status diagrams for the mobile plant (see Figure 2 in Case study 5 of Chapter 12).With a public transport bus fleet the physical assets are mobile and operate over a wide geographic area. The function is to provide a public transport service. The best way of modeling fleets is via a status diagram (see Figure 1 in Case study 6 of Chapter 12).The physical assets of a transmission/distribution system are spread over wide geographic area. The function is to provide electricity to consumers. With privatized utilities the objective is to maximize long-term profitability. With publically owned utilities the objective is to provide a defined level of service at best cost (these objectives are very different and have considerable influence on maintenance strategy).The operation is best modeled at the highest level as a complete generation/transmission/distribution system (see Figure 1 of the Power Utilities case studies introduction). Each part of the system, e.g. distribution can then be modeled in more detail but in the context of the complete system (see Figure 1 in Case study 9 of Chapter 12).R4.2Definition of a unit: A collection assemblies, sub-assemblies and component parts interconnected mechanically and/or electrically to enable the whole to perform a specific production sub-function of the plant.A unit in an open cast coal mine would be a haulage truck.A unit in a bus fleet would be a bus.A unit in a distribution utility would be a transformer.R4.3Many of the sub-assemblies and component parts of a unit have been designed with a useful life longer than the longest production run of the unit, but shorter than the expected life of the unit. Such parts have to be replaced/repaired during the life of the unit to ensure the unit remains reliable during production. By selection of the best possible sub-assemblies and component parts a unit could be designed to be maintenance free over its designed life, say 25 years. This is not done mainly because it would be too expensive but also because in some cases such long-life parts would not be technologically possible.R4.4The replacement of large high-cost units of plant is influenced by many factors to include the availability of capital, taxation policy, production needs, maintenance costs and the availability record of the existing unit. The maintenance managers advice should be sought but in general he does not take the replacement decision.
With industrial plant the physical assets have a fixed location and are connected together via a batch or process arrangement to perform the overall plant function. The function is to provide a manufactured product to a market. The objective is to maximize long-term profitability. The best way of modeling such operations is by process flow diagrams down to the unit level of plant supplemented as necessary by systems diagrams for the services.
With an open cast coal mining operation the physical assets are spread over a wide geographic area and can be divided into mining assets, conveying/transport assets and coal preparation assets. The mining/transportation assets are mobile. The function of the operation is to provide mined coal to a market. The operation can be modeled using a combination of modified process flow diagrams (see Figure 1 in Case study 5 of Chapter 12) and status diagrams for the mobile plant (see Figure 2 in Case study 5 of Chapter 12).
With a public transport bus fleet the physical assets are mobile and operate over a wide geographic area. The function is to provide a public transport service. The best way of modeling fleets is via a status diagram (see Figure 1 in Case study 6 of Chapter 12).
The physical assets of a transmission/distribution system are spread over wide geographic area. The function is to provide electricity to consumers. With privatized utilities the objective is to maximize long-term profitability. With publically owned utilities the objective is to provide a defined level of service at best cost (these objectives are very different and have considerable influence on maintenance strategy).The operation is best modeled at the highest level as a complete generation/transmission/distribution system (see Figure 1 of the Power Utilities case studies introduction). Each part of the system, e.g. distribution can then be modeled in more detail but in the context of the complete system (see Figure 1 in Case study 9 of Chapter 12).
Definition of a unit: A collection assemblies, sub-assemblies and component parts interconnected mechanically and/or electrically to enable the whole to perform a specific production sub-function of the plant.A unit in an open cast coal mine would be a haulage truck.A unit in a bus fleet would be a bus.A unit in a distribution utility would be a transformer.
Many of the sub-assemblies and component parts of a unit have been designed with a useful life longer than the longest production run of the unit, but shorter than the expected life of the unit. Such parts have to be replaced/repaired during the life of the unit to ensure the unit remains reliable during production. By selection of the best possible sub-assemblies and component parts a unit could be designed to be maintenance free over its designed life, say 25 years. This is not done mainly because it would be too expensive but also because in some cases such long-life parts would not be technologically possible.
The replacement of large high-cost units of plant is influenced by many factors to include the availability of capital, taxation policy, production needs, maintenance costs and the availability record of the existing unit. The maintenance managers advice should be sought but in general he does not take the replacement decision.
Capital replacement decisions have to take into account a multitude of considerations: production, maintenance and acquisition costs (and their variation), likely income from sale, plant reliability, fiscal considerations (tax incentives, import duty, etc.), cost of borrowing, obsolescence, alternative investment, etc. The greater the number of such considerations that a replacement calculation includes, the much greater is the complexity of the algebra. In general capital replacement models only take account of a few of the more important variables in any particular case and are, to that extent. always an approximation. The following simplified example is offered as an illustration. It is of deterministic nature in which averaged costs and trends are fairly predictable, as might be the case with a substantial unit of capital equipment.
A fixed-time replacement model for a unit of plant when new, the units-operating cost is 0 (year).Thus, rises linearly with time at a rate I (/year/year) so that after n years the operating cost would be 0 + ni (/year) and averaged over that time the mean-annual-operating cost would be 0 + (ni/2) (/year).
There will also be the cost of raising the above money which could have been done by borrowing (A S)+ for n years (repaying this in annual installments over the period) and borrowing S* for n years (repaid at the time of sale). Assuming simple interest at rate r, and remembering that the amount borrowed decreases steadily, the mean cost of the first amount borrowed would be (A S)r/2 (/year); the mean cost of the second amount* borrowed would be Sr (/year).The total mean borrowing cost would therefore be the sum of these two, which is (A + S)r/2 (/year).
Failure-based maintenance is usually considered acceptable for components with low risk of failure. Risk of failure consists of two components: failure consequences and failure probability. Use-based maintenance is acceptable for components whose failure mode and timing are predictable. Condition-based maintenance is acceptable when the extent of deterioration is measurable.
The required level of serviceability of the structure can also dictate the extent of repairs. For example, small cracks in concrete structures are tolerable in most cases and yet for water-retaining structures and those exposed to chlorides and aerosols they are not tolerable.
A recommended maintenance strategy should be based on scientific data from related studies of ideal irrigation and the requirements and convenience of daily nursing practice. Best-practice recommendations, including preirrigation preparation, irrigation solution [22, 42] and frequency , orientation  and volume  need to be developed and implemented. Before irrigation, nursing staff should check whether blood component or medication precipitate remains in the connecting route through the whole intravenous line. Preirrigation preparation should be done in order to remove residue and minimize microscopic deposits in the whole extension. Based on the literature review [4244, 48], normal saline is recommended as irrigation solution because it is easily available and does not increase the risk of lumen occlusion . The irrigation should be done every 3months . The ideal needle orientation is best achieved by inserting the noncoring needle as close as possible to perpendicular into the silicone diaphragm while keeping the needle opening opposite to the opening of the injection chamber. The orientation of the noncoring needle should not be adjusted to accommodate the wound dressing. The minimum recommended irrigation volume should be the 20-fold of the total intraluminal volume of the implanted ports that revealed by ex vivo simulation . The internal volume of implanted port and intraluminal volume per unit length of implanted catheter should be provided by manufacturers and implanted catheters should be preserved by surgeons. The resulting recommended irrigation volume is therefore 10mL for SVC port and 20mL for IVC port in most clinical scenarios .
Figure 11.3 shows the process flow of the milling plant of a gold mine. The mine is decoupled from the milling plant by the inter-stage ore storage. The milling process is the mines rate-determining process. For the foreseeable future (the next 5 years) management want to operate the milling process continuously. This will result in no plant-level windows of maintenance opportunity. Downstream from the cyclone towers the offline maintenance can be scheduled at unit level by exploiting redundancies (e.g. at any one time only three of the available five thickeners are required).
Scheduled offline maintenance, or failure of the crusher circuit, can stop the whole plant, although the plant can then be kept going for 3 days via the alternative crushing process, but at four times the cost of normal crushing. Scheduled offline maintenance or failure of one of the Ball Mills (or its ancillary equipment) causes a 50% loss of milling production.
The crushing circuit has a mean running time to failure of 6 months. Failure predictability is poor because of the large number of failure modes many of which are induced by randomly occurring production events. The Ball Mills also have a mean running time to failure of about 6 months but with good failure predictability. The main items needing replacement are the rubber lifters and liners.
The location of the mine is such that contract labor is extremely expensive. The resident labor force is manned up to the peak offline maintenance workload and hence is not very productive for most of the time. The quality of the labor is good, with an excellent knowledge of the plant, and in particular of the corrective maintenance methods. Because of the high cost of production downtime the maintenance objective appears to be to maximize milling plant availability.
The crusher circuit is operated-to-failure (or near-failure as indicated by the operators informal monitoring). Since failure is expected there is a considerable level of pre-planning (e.g. preparation of spares, job methods, decision guidelines). When the plant is offline because of failure, opportunity maintenance (including inspection) is carried out on the other units of the crusher circuit. Plant operation is sustained via the alternative crushing process.
The Ball Mills are on a schedule of 4-monthly overhaul. The main job is the repair or replacement of the lifters and liners, but other work is carried out on the mill to ensure its reliable operation over the following 4 months. In addition, preventive maintenance is carried out on other units in the stream (e.g. the conveyors). This causes a workload peak and contract labor has then to be employed. Some of the work is time-based, some deferred corrective maintenance, but most is repair-on-inspection.
While the existing fixed-time approach (4-monthly shutdowns) for the Ball Mills may not be the best policy it is regarded as an effective one. Explain why this is so? How do you think this approach could be improved?
Solutions to problems of this kind cannot be the exact ones. The proposals below must be regarded not as optimal solutions but as guidelines to good solutions. Various number of points raised are open to debate.
The factors that could be neglected are standards of safety and plant condition (longevity). Corporate management must be made aware of the link between maintenance effort (and resources) and safety.The budget must take into account the longer-term major maintenance work that influences equipment longevity.
The adoption of a condition-based approach could extend running time of units without reducing equipment reliability. This, however, assumes that a monitorable meaningful parameter can be found. If this is the case, condition-based policies would improve unit availabilities and also reduce maintenance costs. The downside of this could be that the workload might fluctuate erratically (perhaps with very large peaks). It would not be easy to co-ordinate maintenance work with production requirements or to use the common centralized maintenance resources efficiently. If the workload varied erratically across such a large plant, the organization would need to be designed to match, i.e. resources would have to be plant- flexible or greater use would have to be made of contract labor.Based on the limited information given it would seem likely that if condition-based maintenance were introduced as the strategic driver it would be a more cost-effective strategy. Because of the nature of the process equipment (failure mechanisms such as wear, corrosion, etc.) it should be easy to find condition-monitoring techniques that would be effective in predicting the onset of failure. The lumpiness of the maintenance workload that might result from such a policy should be able to be overcome by improved production-maintenance planning coupled with condition-based lead times and resource flexibility.
Based on the limited information given it would seem likely that if condition-based maintenance were introduced as the strategic driver it would be a more cost-effective strategy. Because of the nature of the process equipment (failure mechanisms such as wear, corrosion, etc.) it should be easy to find condition-monitoring techniques that would be effective in predicting the onset of failure. The lumpiness of the maintenance workload that might result from such a policy should be able to be overcome by improved production-maintenance planning coupled with condition-based lead times and resource flexibility.
If the fixed-time policy were largely retained, condition-based procedures might still be adopted, for two reasons, viz.:To help predict the corrective work needed during shutdowns, this improves planning.To avoid unexpected failures.
A base-load power station shutdown might well take 12 weeks and employ as many as a thousand artisans. The date must, therefore, be fixed some considerable time ahead, to facilitate the necessary extensive planning and resourcing. The maintenance workload might have a peak/trough ratio (shutdown/normal) of up to 10:1, which would necessitate the employment of contract labor. The fundamental difference between the power station and refinery strategies is caused by the difference in the way the plant is designed and operated. This in turn governs the shape of the workload. For the refinery, the major work can be smoothed over the year and carried out by an internal labor force; for the power station, extensive use of contract labor for resourcing the shutdown peak will be necessary.
Option (iii) is already in use and is proving too expensive. If option (i) is considered (as it must be) the causes of failure need to be identified and options considered for their elimination. This, however, is a long-term approach and the most cost-effective attack is likely to be the adoption of a condition-based policy. The information given is that the main causes of failure are wear, corrosion or fouling. Therefore, for most items, monitoring techniques for predicting failure can probably be found and effort would need to be directed at the historically unreliable items. This might allow maintenance of the crusher circuit to move from operate-to- failure to a policy based on condition-based shutdown (albeit with short notice) plus opportunity maintenance. Even with such short notice the monitored information (and history) should facilitate improved preparation and planning.
The main reason for Ball Mill shutdown maintenance is the replacement of the 0 lifters and liners. Their deterioration is time related and is statistically predictable so fixed-time replacement is an effective policy for controlling their reliability. It is not unlikely, however, that some form of condition monitoring might facilitate running the Ball Mills for longer periods before the lifters and liners need replacing. In many cases this would take the running time past 6 months and in some cases it might be as little as 4 months. However, if the inspection techniques gave an adequate planning lead time, the advantage is that the shutdown could still be scheduled.
Generally, the maintenance strategy is classified into two categories, based on the repair timing: corrective maintenance and preventative maintenance (DoD, 2008), as shown in Fig. 23.7. In corrective maintenance, the repair or retrofitting activities are only performed after the facility fails to meet the requirement of operation. Preventative maintenance tends to prevent the incipient failure of a facility through previous interventions at periodic or predicated times. For a tunnel, the maintenance plan is usually made during construction stage; however, during operation stage its adjustment should be periodically conducted, based on the degradation condition. In addition, the maintenance strategy should strike a balance between preventative and corrective maintenance, according to the facility function and operation conditions (FHWA, 2015). For a pipeline tunnel under desirable conditions, corrective maintenance may be effective. In contrast, for a transportation tunnel, preventative maintenance should be performed within a safer limit designed in advance.
In practice, tunnels deteriorate in various ways, depending on the material used, the support system, the operation condition, and etc. One tunnel may degrade slightly over a long period, whereas the another one under serious operation conditions may deteriorate to the serviceability limit over several years. Additionally, the influence of deteriorations on a concrete tunnel varies depending on its type, location, and size. Accordingly, the deterioration tendency over years of a similar tunnel should be referenced to make and modify a maintenance plan. If the tunnel is vulnerable to severe deterioration, the preventative maintenance should be considered, otherwise, the corrective maintenance may be more desirable. Nevertheless, the maintenance strategy should also take into consideration the LCC.
Typically, an operator proceeds to itemize basic goals. The highest priority is to maximize production. Optimizing production per unit of energy is part of that aim. Maximum availability and reliability (i.e., no unplanned downtime) are also critical. Operators struggle with financial budgets and the pressure of reducing costs in the attempt to minimize maintenance, service, and repair activity.
Too little maintenance results in unexpected failures and consequential major losses of production and/or customers (Figure 7-1). This impractical approach is termed reactive strategy and should be avoided on all important machinery. Optimum maintenance strategy balances reasonable costs with maxmium possible availability and reliability. The two main maintenance strategies employed by companies today are labelled predictive strategy and preventive strategy. These are part of a balanced approach as shown in Figure 7-2.
Predictive maintenance strategies operate without a regular plan for service work or exchange of parts. A maintenance plan is only set up if there is proof of deterioration. Consequently, a company with a predictive strategy favors minimizing cost over maximizing use. The annual cost of this strategy may typically only average 1%2% of the prime equipment price.
In contrast with the predictive strategy, a preventive strategy aims toward maximum safety against unexpected failures. The basic concept is to predict the average lifespan of a part and then replace it before the end of that lifespan. Annual cost is therefore higher (8%10% of the prime equipment price) because it is necessary to purchase and warehouse more spare parts.
Aside from the effects of a given maintenance strategy on troubleshooting time and effort required, the application service of the unit also has an effect. With increasingly tough environmental legislation that in turn demands maximum energy usage and/or recovery, power recovery processes are increasing in number. The deregulation of the power industry that results in the increase of small power producers (such as process plants) also serves to increase this number.
A profit-centered maintenance strategy requires effective and reliable maintenance planning, estimating, and scheduling (RMPES) and many other best practices. RMPES is considered by me and many others as one of the most important maintenance best practices because it is a very important enabler of profit, gained value customer service, craft labor productivity, and physical asset productivity. Effective and reliable maintenance planning, estimating, and scheduling enables:
The last of the three maintenance strategies to look at is condition-based maintenance. CM involves regular inspections of the equipment and removal of those components that the monitoring technique indicates are about to fail. CM is often advocated to be the cheapest maintenance strategy. The cost of CM is assumed to be $25/tube/year ($100 every four years). A comparison of RM and CM costs is presented in Fig.10.7. As can be seen, whether RM or CM is the cheaper depends wholly on the effectiveness of CM at preventing forced outages. If CM is 100% successful, then this is by far the cheaper method. However, if CM does not stop 10% or even 1% of potential tube failures, then RM tends to be cheaper.
Consider the following periodic maintenance strategy for a FTC system described by Xn in Fig. 1: The initial state of the system is assumed to be fault-free, 0=0=0; for every period TM, if the system is up, it goes to the maintenance state which brings the system to the initial state; and if the system is under repair at TM, we continue the repair, after which the system restarts from the initial state.
This maintenance policy and operation cycle can be considered as a special case of the system described in (Bloch-Mercier, 2000), and we therefore have the following result available for maintenance scheduling.
Lemma 1. (Bloch-Mercier, 2000) The mean duration time of maintenance and repair are denoted as SM and SR respectively. The reliability function of the system without maintenance and repair is denoted as R(t). The stationary availability A2(TM) of the overall system with maintenance period TM is then given as follows:
It implies that the stationary availability is monotonously increasing when TM is large enough, and the best strategy is not to take maintenance. So the relation between f(TM) and SMSR determines the existence of optimal maintenance period, as summarized in the following theorem.
Each company or site should have clear safety guidelines outlining best practices for the entire site, as well as when working with crushers. Before even stepping on site to work with your sites crusher, employees and operators must be trained on all safety procedures of your site and crusher.
For instance, is the operator clear on warning signs to look for, emergency stop locations and appropriate walkaways? Make sure the operator or maintenance personnel perform a hazard analysis before each new operation. Conditions such as time of day, weather and area around a piece of equipment can all affect the operation about to be performed.
It is also a good idea to have a fresh set of eyes look at conditions. Even when someone is experienced and well trained, it is very easy to see the same thing day after day and accept the way things are or even miss something.
The aggregate industry is heavily regulated, but regulations alone will not make managers, workers, contractors and others safer or better safety stewards. If a company wants to achieve high safety and environmental standards, that company and the communities in which it does business cannot achieve these goals through fear of retribution for non-compliance.
To be successful, the industry must rise above the mentality that it is simply complying with regulations, inspections and penalties, and instead focus on these areas because it is the right thing to do. A good place to start is to provide effective signage, keep the site clean, walk the site daily and maintain quarry faces and haul roads.
Dont allow yourself to turn a blind eye to a hazard or a hazardous situation. Dont allow yourself to say, Its not my job or Im not the one who left it there or someone else will fix it. Every incident, accident or event should be investigated. Through these investigations, recommendations should be made to improve safety and to prevent the event from occurring again.
While new technologies and equipment are emerging every day to make the workplace safer, your best resource is your workforce. Its not only important to make sure employees are trained on the safety procedures of the workplace, but also on the proper use of their machine.
Untrained, unknowledgeable work staff can lead to an unsafe work environment. Just because a person is on your site working with other equipment doesnt necessarily mean they are trained on the proper use of a crusher or a breaker. Do they know proper feed size and capacity? Not knowing these can lead to oversized material entering the crusher and cause malfunction.
Safety on a crusher starts with the person feeding the plant. The person feeding the plant needs to be trained on best practices specific to the crusher they are working with. An operator may have years of experience operating and loading a cone crusher, but that doesnt translate into experience loading and operating a jaw crusher.
Operators need to be trained on what to look for to prevent unnecessary maintenance. Spending the time and resources to train your operator not only leads to a safer workplace, but it ultimately increases production. The safer you are, the more productive you are.
When operators proactively keep their crusher running safely and effectively, they increase production. A couple of minutes spent on cleaning or maintenance can lead to hours of productivity later and an overall safer working machine. Operators should also keep detailed records of maintenance and other issues.
Make sure your operator is in protective clothing. Also, when you reach the crusher, make sure all guards and safety devices are in place, secured and functional before operating. Be sure to review and follow all lockout, tagout and tryout procedures for the crusher when performing equipment maintenance, repairs or adjustments.
Additionally, keep your crusher working safely and efficiently by performing regular maintenance inspections. This allows you to pinpoint problems that may make the machine unsafe to use. Some tips to keep a safe crusher: Operate at the appropriate capacity. Keep platforms and areas around the machine clean. Ensure lubrication, flow, temperature, wear and pressure are monitored.
Safety is something that can be practiced and planned daily, monthly and yearly. Try to make yourself or your workspace safer every day. Clean up hazardous debris. Walk to your workstation a different way to see if you notice anything unsafe.
In our industry, hazards are everywhere due to the nature of our business and the equipment and tools we use. When less-than-desirable housekeeping practices are present, they add unnecessary hazards to the workplace. Housekeeping takes a lot of time if it is practiced once in a while, but it takes virtually no time at all if it is practiced continuously.
Its important to make sure your crusher operator follows all operational guidelines and that all safety best practices are in place. But also take the time to make sure your entire site is properly trained on site safety procedures and best practices. Hold regular safety meetings to review new procedures or address any safety concerns. Set yearly safety goals and commend operators on years of safety excellence.
The operating skills that are needed to be developed are almost identical to the ones that we just finished discussing with the gyratory. The same operating variables and job perimeters are in effect here as well so I wont go into them. Before getting into the next chapter there are a few Jaw Crusher Safety tips that I would like to mention.
When a crusher breaks a rock, small pieces may become airborne. This is known as PLY ROCK and can be quite dangerous, especially to the eyes. For this reason proper safety glasses or goggles should be worn at all times.
All the Crushing Plant equipment is interlocked, except for the sump pump, and therefore, the plant must be started from the fine ore bin back. The dust collector and scrubber bottoms pump are interlocked together, and must be started prior to other equipment. The sump pump should be placed in AUTO. The drives should be started in this order:
Normal Crushing Plant Operation After the crushing plant has been brought up to normal operating conditions the operator should attempt to even out the feed to the jaw crusher to the design tonnage of 60 mtph. This is achieved by ensuring that the feed to the crusher maintains an essentially full chamber without ore spilling out. Adjust the speed of the apron feeder with to increase or decrease the feed rate to the jaw crusher and ultimately to the crushing circuit.
The product from both crushers should be visually checked to ensure that each crusher is producing the desired product. If the jaw crusher product increases in size, the cone crusher may become overloaded. Similarly, if the cone crusher product increases in size, the circulating load around the cone crusher will increase, consequently, increasing the load on the cone crusher and decreasing throughput.
The Crushing Plant operator must monitor the cone crusher power draw displayed on the cone crusher ammeter. The ammeter should show no major fluctuations and should read approximately 100 amps. An excessively high power draw on the cone crusher indicates the cone is being overloaded, which may be due to a high feed rate or a blinded screen.
The operator must pay close attention to the cone crusher lube system. A low pressure alarm will sound if there is an abnormally low oil pressure. If this alarm sounds, the crusher will shut down after a timed delay. If the crusher is allowed to operate longer than 2 minutes after the loss of oil pressure, serious damage to the crusher may result. If the pressure gauge indicates pressure above the normal operating pressure, shut down the cone crusher and investigate the problem. Likewise, a high temperature alarm will sound if there is an abnormally high oil temperature in the oil return line. Shutdown the crusher and investigate if the temperature of the oil pipes seems excessive. Low oil pressure or high oil temperature may be caused by several conditions;insufficient oil supply in the lubrication system, a broken oil feed line, oil pump failure or excessive bearing wear in the crusher. Either condition must be thoroughly investigated as to the cause of the alarm.
Although there is no variable control of the beltconveyors in the Crushing Plant, the operator should regularly check conveyor discharge chutes to ensure there is no undue buildup of material. This is especially important if the feedmaterial is clay-like or excessively wet.
The Crushing Plant operator must ensure that the dust scrubber has an adequate supply of reclaim water and monitor flow-meter to ensure that the proper amount of water isbeing recirculated through the scrubber. Under normal conditions, the dust scrubber requires a minimum recirculation of 8 to 10 cubic meters per hour. A lower flowrate will ultimately cause excessive wear on the scrubber and a higher flowrate is a waste of reclaim water and may hinder operation of the grinding circuit.Get in Touch with Mechanic