Improving Tailings Management in Mining Operations

by , | Feb 9, 2022 | Metals, Mining, Minerals, Valves, Actuators & Regulators

Jim Cahill

Chief Blogger, Social Marketing Leader

Podcast on mining tailings managementThe effective management of tailings in mining operations is critical to the overall performance of the mine site. Managing the slurry flow reliably and efficiently requires valves that can withstand this difficult and abrasive process.

Emerson’s Andy Coxall joins me in this podcast to discuss the challenges in tailings management, the problems with valves not suited for this severe-service application, and why severe-service knife gate valve technology such as the Clarkson KS1 is the best choice for these challenging slurry applications.

Visit the Mining, Minerals & Metal and the Clarkson sections on Emerson.com for more on the technologies and solutions to drive performance improvements in safety, reliability, efficiency and production in your mining operations.

Transcript

Jim: Hi, everyone. I’m Jim Cahill and welcome to another “Emerson Automation Experts” podcast. A critical function of any mining operation is how a site manages the uneconomic fraction of what is taken from the ground. This byproduct of the mining process represents an engineering, and increasingly an environmental challenge for operators. Today, I’m joined by Andy Coxall to discuss how mining operations can cost-effectively rise to the tailing management challenge while meeting their sustainability goals. Welcome, Andy.

Andy: Hi, Jim. Nice to be here. Thanks for having me on.

Jim: Well, it’s great to have you all the way across the world joining us here. So let’s begin by asking you to share your background and path to your current role with our listeners.

Andy: Sure. So I’ve been with Emerson for over 20 years now, and predominantly with our isolation valves business unit, in its many forms, that it’s transformed through over the journey through multiple owners, and ultimately here we are at Emerson. And, yeah, we’re really enjoying our time in the Emerson family. So I’ve been in product from predominantly involved in the mining industry. So my area of expertise, in knife gate valves specifically, is very much in mining market-dominated products. And here in Western Australia, where I currently reside, obviously, we’re a very, very large mining jurisdiction, so Emerson knife gate valves and mining itself will tend to go hand in hand. So I’ve had a variety of roles within Emerson over the journey, everything from our document control to our internal sales, field sales representative, and more recently, our Asia Pacific Business Development Manager.

So obviously, in the current environment, we traveled very restricted. I’ve been almost isolated here in Western Australia, for the best part of two years. However, before the rolling lockdowns across the globe, I was doing a lot of traveling through Asia as well developing our impact partners, and our relationships with our mining customers in the Asia region. Obviously, the last couple of years that’s made that very difficult, but for the most recent parts here in Australia, and fortunately, our mining industry, particularly here in Western Australia, is largely unaffected by, obviously, the events that are happening in the rest of the world at the moment. So we’re very fortunate. So I have looked after a number of different industries, our process, and the water industry, however, all roads have led me back to mining, and yeah, that’s where we are today.

Jim: Well, that’s a great background. And let’s hope as we get further into this year, you can get back to going all over Asia wherever it takes you. So thanks so much for that introduction. So today we’re going to be talking about tailings management for mining operations. For anyone in our audience that may not be familiar with the tailings term, what are they?

Andy: So tailings are essentially the leftover materials or the wastes in a mining process. So after we’ve separated the uneconomic fraction of the mineral ore known as the gangue, essentially anything that is not the material that we are looking to extract. So for example, if we’re mining gold, copper, tin, iron ore, coal, whatever that precious metal is, or the commodity that we’re trying to extract, the remaining material, the gangue, is the waste and the tailings. So we refer to it as tailings, and specifically, when the tailings are removed, they need to be managed. So they’re most commonly produced during the separation and recovery phases of the mining. And the tailings or the waste, the gangue, it’s managed throughout the entire process, from digging in out of the ground to essentially shipping off the commodity that we’re trying to separate.

Jim: So why is the tailings management important for a mine site?

Andy: So the tailings, they must be collected, transported, or dispersed into what we’d call tailings storage facilities, or collection ponds or dams, depending on the terminology of the part of the world that you’re in. But the industry term is probably tailings storage facility. So this is where we store our tailings or our gangue, or our waste, where it is a waste product. It has no economic benefit or use, so it doesn’t need to be stored for the life of the mine. So in the event that the tailings can’t be effectively separated from the mining process, the operation…the entire mining operation can grind to a halt. So the management of tailings is very important. Essentially, if we have some failures on the backend, or the waist, or the tailings end of a mining plant, it does bottleneck the rest of the plant. So if you’ve got a blockage or a failure, or some sort of event at the backend of the plant, we really can’t feed anymore raw material into the frontend of the plant.

And as such, with poorly designed equipment or flowcharts, we tend to see the whole operation grind to a halt. So that’s the importance of getting the tailings out efficiently from the backend of the plant. And then obviously, as the tailings are dispersed, and they’re pumped away from the mining plant to their storage facility, extreme care has to be taken in the design and the management of that tailing facility to ensure that no unnecessary harm or alteration occurs to the environment and in the personnel as well. So I’m sure anyone who’s familiar with the mining industry will remember that there’s, obviously, been some very…several very well-publicized tragedies that have occurred due to the mismanagement of tailings operations that have had really catastrophic consequences for the environment and, of course, human life as well. So there’s a massive focus on the management of tailings across the globe at the moment, and rightly so, because vast amounts of waste are being stored, and they need to be stored and transported effectively and safely to ensure that there’s no harm done to the environment or to human life.

Jim: Wow, it sounds like there’s the safety, environmental, and not to mention production. So, you got to do it right, or you can have serious impact across all of those. Why are valves important in tailings operations design?

Andy: So, the valves play a critical role in particularly the transportation and the disbursement of the tailings. So, essentially from securing our pumping facilities with regards to isolation, to controlling the flow, and the even spread of a slurry across the tailings storage facility to prevent overflow and uneven disbursement, and obviously, environmental spillages and incidents. So, essentially, a mining plant will have a tailings disposal pumping system. So the tails will be, or the waste will be transported via pumps from the plant to a tailings storage facility. Now, in some instances, and environmentally the safest or the most obvious place to store tails may not necessarily be right next door to the plant due to environmental factors for the geography or the topography, for example, or close to the plant, obviously, is where they’re digging for the ore. So they don’t want to be transporting the ore vast distances to the plant. So this tailings storage facility can sometimes be many, many miles, or kilometers away from this tailings facility.

So, essentially, all these tailings valves, it’s an extremely tough application of valves. It is probably the most arduous or severe service in mining that there is an entire plant. So the disposal of waste is a really critical factor. And when we think about the distances and the volume of waste that we have to disperse, this, in turn, means that our valves have to handle high-pressure, abrasive media. They have to handle high velocity. So essentially, the waist is very, very, very fine, fine particles. They’re very fine mud essentially. And this is very abrasive. So when we add pressure, when we add density, when we add velocity, we tend to see a very, very arduous environment for a valve to operate in. It really is one of the toughest applications a valve can be exposed to. So because we do need to direct the tailings or the waste in certain directions around the pond to disperse it evenly. So essentially, we want to feel our dam up evenly, so that we don’t have all the tails just being pumped into one end of the dam, and it builds up and obviously, we’ve got uneven dispersion. So the dam needs to be filled evenly.

So essentially, we have a ring main that goes around the top of the dam. And depending on the size of the dam, we could have hundreds of valves around the top of that dam that will open and close to evenly disperse, and evenly fill the dam up depending on the state and the density, and the composition of the tailings. So it is a process that is quite technical and does take some serious management. So valves are very, very important because we often do see poorly specified valves failing early and failing often due to all of the factors that I’ve just mentioned. So when a valve fails, particularly if it does shut down the pumping station, for example, that places a heavy cost and a heavy burden on mine operators, which endangers the sustainability credentials of the entire operation. So valves although are small spend in the scheme of a mining…the build of a mining processing plant, they are very important.

Jim: Yeah, it seems like abrasive materials, pressure, density, the fact that you need to make sure it’s shut off in there that it sounds like valves are really a critical piece of that. So why do we see poorly specified valves in such a critical application?

Andy: Sure. So, as I mentioned earlier or just before, so valves are a very small spend in relation to the overall CAPEX, or the cost to build a mining plant. And they do get overlooked. So there can be, depending who’s designing and building, and procuring the equipment for the plant, this perception that because the valves are relatively inexpensive in comparison to, for example, our big pumps and the pipe that the specification and the selection of the valves are not quite as important. And they do get overlooked. And sometimes just get thrown into the basket of all valves are the same, and any valve can do the job that are needed to do. So it’s only natural that mine owners and their EPC counterparts are looking to get started up in the shortest time possible and obviously, with the lowest total installed cost. So if we can save some costs of some valves, that eases cost pressure, not only on the valve spend but elsewhere where there might be overrun. And particularly valves that are highly engineered for long service life.

So for specifically for tailings management, these typically come at a prohibitive upfront cost. So in this environment where we’re looking to reduce costs, obviously lead time, this is where the valve spend does get compromised. So essentially, restricted capital budgets are often forcing the selection of lower quality process equipment that will unfortunately invariably fail more rapidly. So it’s, as a business development manager myself, this is my role to educate our customers, and our EPCs, and our colleagues in the industry that the, particularly in the tailings management part of the plant, that the valve specification, certainly justifies a little bit more thought and perhaps maybe a slightly higher budget allowance to allow for a properly engineered valve to be installed in these critical applications.

Jim: Yeah, so what are these, I’ll just say, less than ideal valves mean for owners as the mine moves into the operational phase?

Andy: Sure. So when we have valves, we have broad statements, one-size-fits-all, or one design is appropriate for the entire plant. And we do often see one type of valve installed all the way from the front end of the plant, all the way through to the tailings management system. And this is where we start to see real problems. So where we have a design that’s not fit for purpose, some of the more critical failures that we see is the inconsistent isolation. So we have a valve that we need to isolate this particular pump, so we can transfer and start-up our standby pump. So if we have an inconsistent isolation where the valve is not closing correctly, we will have issues with isolating the duty pump safely. And also if we need to perform downstream maintenance. So if we need to isolate a valve to work on a pump that may need some maintenance, if the valve is not closing 100% and providing us a leak-tight shutoff, downstream of that valve is, obviously, not safe for personnel to perform maintenance on any equipment that’s downstream of the valve.

So what we’re saying is that it extends outages. It poses a safety risk to service personnel who need to perform maintenance works downstream of the valve, and it really does cause big headaches for our customers, or for our end users, and obviously, the frequent downtime. So both planned and unplanned downtime, this impacts throughput, what we’re putting through the plant, obviously, and what we’re extracting. So the commodity that we’re extracting, anytime that the plant is down, the company’s not making any money. So we really, as a valve manufacturer, we really don’t like to see valves causing downtime on plants. It really is a lot of the time unnecessary because it’s all down to the selection of the valve. So if we can specify a valve that will particularly last for the anticipated runtime in-between shutdowns with our customers, we can really take that valve headache away, and of course, increase total cost of ownership.

So if we’re regularly replacing valves, if we’re regularly repairing them, so we’re required to hold spare parts, spare valves, if we need to send operators out to the field to attend to a valve to try and get it to operate, to open or close. This is increasing directly or indirectly, the total cost of ownership of that asset or that valve. So a lot of the time we don’t see our end users considering a valve an asset until it starts causing them problems. And then consideration needs to be made as to what do we need to do to this valve, or what valve do we need to put into this application to stop this unplanned downtime and causing me all sorts of headaches?

Jim: Well, yeah, it sounds like there’s a lot of operational and economic problems there. So it seems like there’s a real opportunity for an innovative solution.

Andy: Yeah, it is. It is. And it’s one that Emerson, I believe, is uniquely positioned to solve. So through our Clarkson brand, we’ve been working together with our clients, our mine operators for over 50 years. And through that journey, we’ve obviously, continuously improved our slurry valve technology, concentrating primarily on the toughest application. So we pride ourselves on solving tough applications for our customers and providing them products that will endure and provide largely trouble-free operation for the severe services. So we’ve really developed an intimate understanding of the materials, the design, the components, and the features of the slurry valve that really matter to deliver the performance that our end users, our clients, these mine operators really need. And all that we’ve learned, over the last 50 years, we’ve engineered these features, these ideas into our latest valve, and that’s the Clarkson KS1. And we’ve incorporated them in an innovative way…Sorry in an innovative way that makes the valve attractive to…particularly to EPCs in the design phase of these particularly greenfield plants.

Jim: So and in these type of slurry valves, and particularly with the Clarkson KS1, what are some of the performance improving features that you mentioned?

Andy: Sure. So the KS1 is a product that we’re…we’ve been anticipating for quite a while here at Emerson, and we’re very excited about it now that it is released. So the KS1, the primary benefit, and feature of the Clarkson KS1 is its heavy-duty, precision-molded elastomer seat. It’s one of the true differentiating features that benefits operators, and it’s our differentiator from other severe service valves that are in the market. So there’s many valves in the market that play in this severe service space. However, the majority of those designs all use a thin O-ring seal to provide the sealing interface between the gate and, obviously, the sealing surface. So, these thin O-rings are really prone to wear and displacement during the open and close cycling. So the KS1 has the largest cross-section of seating real estate in the market for these severe service applications. So this gives us confidence that the KS1 will provide 100% zero-leakage shut off or isolation many times more than what our competitors can do in the market.

Also, we’ve got our patented gate edge seal. So the gate edge seal secures, or provides us a full seal of the valve, and prevents any leakage through the top of the valve. So obviously, our Clarkson KS1 is an enclosed body valve. It’s not a more traditional push-through valve where the valve discharges on every cycle. The severe service valve contains all of the media inside the valve body. So obviously, we have a gate moving up and down through the flow, for those that are familiar with knife gate valves. And to prevent any leakage to atmosphere through the moving part, so through the gate, we have a gate edge seal. The compression of this seal can be adjusted externally, while the valve is online for convenience and for maintenance purposes. So a couple of very key features that the KS1 brings to the table. And the combination of these really does make it one of the best valves in its class.

So we also have a full round port, okay? So a full round port is very important. We spoke earlier today, Jim, about the turbulence and the abrasion, and the high velocities that these valves see. So if we have an uneven diameter in our pipeline, what we’re creating is turbulence. Turbulence creates wear not only on the valve but downstream of the valve this turbulent flow destroys components. So we have a full round port in the KS1. We don’t have any straight sides. This is very important because we are minimizing that turbulence across the valve. This extends not only the life of the valve itself but more importantly, any assets that are downstream of the valve. So pumps, pipe spools, bends, particularly lined pipe can be very expensive, and we don’t want our valves contributing to the wear and tear of that infrastructure.

And finally, the last key feature of the KS1, the replaceable and rotatable inlet, and outlet wear rings. So these provide additional protection, for the internals of the valve, against the abrasive media that is, obviously, passing through them. So simple adjustments to these wear rings can extend the life of the valve at no extra cost to the customer. So there’s four or five really important features to this valve that differentiate it from others in the market. And we’re really excited to launch this and we’ve, obviously, taken our initial orders over the last few months for the valves and so far, so good. It has met our expectations.

Jim: Well, that sounds like a number of really nice innovations. And they’re available for mine operators to solve such a persistent issue with wear that these other valves experience.

Andy: It is. It is. It really is. So the Clarkson KS1, it achieves zero leakage shut off time and time again. And this extends that process uptime that we’re talking about, particularly in these very heavy slurry applications that we see in the tailings management systems. So again, this is where we see rapid and repeat valve failures. Every site almost we go to we’ve seen; they’ve had issues over the journey with valve failures in these arduous applications. So the cost savings are there for the operators too. So with greater reliability and maintenance intervals, our customers, our end users are able to extend and to save on labor and parts for these valves because they are not requiring ongoing maintenance as much as the more traditional valves that they have been using. So also when we do need to service the Clarkson KS1, for example, these maintenance events themselves, that are planned for maintenance on these valves, are shorter and can be completed in the field. So there are numerous benefits to a higher engineered valve than what we’ve seen in the past.

Jim: Yeah, we’ve spent, you know, the bulk of this podcast talking about the tailings application, but is the Clarkson KS1 valve available or a good fit for other type of applications?

Andy: Yeah, definitely, definitely. So, tailings are, obviously, our target market for tailings, however, it is not isolated to that particular part, particularly in the mining process. So essentially, anywhere in the mining process where we have high pressure, high density, high cycling, high velocity, or any combination of high particle size even, and anytime we have a combination of any one of these factors is where the KS1 can be used reliably where maybe in the past we’ve used a cheaper commodity style valve. So anywhere where our customers don’t want a valve to discharge. So particularly with our gold and copper miners, for example, where they’re using some pretty serious assets to extract the precious metal from the ore, and they don’t want a valve that discharges product to atmosphere every time it opens and closes, the KS1 is non-discharging.

So even though we may not have high pressures and high velocities in some of those applications, just the pure fact that it does not discharge, and can provide a reliable isolation, lends itself to those applications just on those mere facts that it doesn’t discharge, and it is available in a variety of materials that can withstand those assets. So, outside of mining, the KS1 will thrive in other businesses such as particularly oil sands in Canada, the power industry, and pulp and paper. Pulp and paper is a notoriously difficult industry or has a notoriously difficult process for knife gate valves to reliably isolate. So particularly our friends in North America and our colleagues over there are having success with the KS1 in pulp and paper. So, yes, it was designed for mining, but because it is such a robust valve, and it’s been designed for these really arduous services, it can be transferred across other industries.

Jim: Well, that makes sense in things like oil sands and pulp and paper, and then there where it corrosive and erosive type of flow going through there does sound like that would be a great fit. So let’s wind things down. Where can our listeners go to learn more about Emerson’s tailing solutions and the Clarkson KS1?

Andy: Sure, sure. So, our listeners can visit, obviously, amazon.com to explore not only the KS1 but many other of our mining industry solutions. So the easiest way is to just go to Emerson.com and navigate through to the isolation valves business unit and to the KS1 particularly. Or an even simpler way is to simply type into Google, or a search engine, Clarkson and KS1, and it’s the top result there. And that has a wealth of resources. So we have general arrangement drawings, 3D models, installation operation manuals, and the technical datasheets, along with a lot of other information on this valve. So we have a comprehensive library there of information pertaining to the Clarkson KS1. And stay tuned with this KS1 is a…and I failed to mention this earlier, but it’s the [ASME] Class 150 pressure-rated knife gate valve. Very soon, we’re launching our Class 300 pressure valve, which gives us all the benefits of the KS1 that we’ve discussed, however, it will be rated to ASME Class 300. So, not only will we have a full KS1 Class 150 severe service knife gate valve, we will have the Clarkson KS3 ASME Class 300 knife gate valve, which again, we’re very, very excited for. So stay tuned for that release in the coming months.

Jim: Well, that’s exciting to know that that’s coming on there, and even extending the range of applications that it’ll fit into. Well, Andy, I’ve sure learned a lot. I know more about tailings than when we started this podcast. So, thank you so much for sharing your expertise and mine tailing challenges, and the importance of getting the valves in there for safe, reliable, efficient operations there. So thank you so much for sharing that with our listeners today.

Andy: Well, thanks, Jim. Yeah, it’s really been a pleasure. So, yeah, look forward to talking to you again soon on, yeah, our new and upcoming innovations. So, yeah, it’s been fun. Thank you very much.

-End of transcript-

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The opinions expressed here are the personal opinions of the authors. Content published here is not read or approved by Emerson before it is posted and does not necessarily represent the views and opinions of Emerson.