A Hub for Mining Engineers
A history of mining translates into high levels of technical expertise
Many mining companies enjoy operating in Nevada thanks to the jurisdiction’s favorable geology and what they see as regulatory agencies that strike a fair balance between environmental stewardship and the promotion of successful business operations. Importantly, the State is also home to a suite of engineering consultancies that offer services for all sectors of the industry, allow mining companies to make the most of this environment. While each company has its own specialties, as a whole, the engineering sector is working to promote more efficient water management, build more robust heap leaching facilities, and introduce digital technologies to boost mining productivity.
Water and the environment
Water, an especially precious commodity to the driest State in the US, is used in a variety of ways in mining. It is often critical for ore processing, dust suppression, slurry transport, and sometimes to go deeper within the ore body. Operators have to be mindful of not simply the amount of water they use but also where that water goes — mine drainage of metal-rich water can contaminate drinking water, harm regional plant and animal life, and create acid runoff strong enough to corrode infrastructure. As the industry at large strives to alter its public image to being a steward of the environment, water usage plays a critical role in the transformation. Engineering and consulting firms help mining companies in Nevada make the most of the resource.
Environmental consulting firm Broadbent & Associates operates in Nevada to help mining companies comply with State regulations regarding the protection of groundwater. “Mine sites need to obtain water pollution control permits, which are focused on the protection of the water resource,” explained VP and principal engineer Randy Miller.
The company assists in sampling and testing to ensure the water is properly taken care of in addition to remediation work on contaminated water or cleanup projects to help with closure of legacy mines.
“An important challenge that the industry will face going forward is the allocation of water. How to share and maintain available water to keep the industry growing will become a very strong component in the decision-making processes.”
Scott G. Britton, Manager US, Mining Plus
Tierra Group lends its engineering expertise on water management and tailings to mining companies throughout Nevada. The company’s hydrologists, hydrogeologists and hydrochemists are particularly adept at dealing with the exploration and development of surface and ground water supply, balance, storage, distribution and treatment. Additionally, the company specializes in the construction of tailings to ensure toxic waste does not contaminate water supplies. Speaking of the company’s work on mine closures, founder and principal engineer Pete Kowalewski explained: “Often, when dealing with a tailings facility or water storage facility the closure is two-fold. You have to go through the actual closure process with the environmental regulatory body in the State of Nevada, NDEP, as well as the division of water resources. There, you have to do a dam decommissioning project to ensure that the facility is no longer able to impound water.”
Besides the operational components of running and closing a mine, mine planners must also take into account human needs, especially at remote sites and over long-term operations. Forsgren Associates provides the industry with a different type of water management service by applying its 60 years of civil infrastructure experience to designing mines. “Mines are typically remote, and like cities, require their own infrastructure for drinking water, wastewater processing, and storm water management,” explained VP and director of mining services Alan Driscoll.
Forsgren has taken on water management projects to provide the engineering and permitting support required to consolidate operations between mines, to help mines de-water their operations, and to create water systems as mines ramp up for operation. Driscoll acknowledged that given the challenging terrain of Nevada, his team has to be able to keep their plans flexible. “Nevada is fairly dry, and the water does not behave well — it is usually not present where you need it, present where you do not want it, and very difficult and expensive to move from one place to another. Additionally, mines are dynamic in nature. As a result, strategies for managing water at a given site are constantly in flux.”
Heap leaching has become a popular processing method as its lower cost can boost the economic viability of a project. Especially for large-scale mining operations, the process is much cheaper than more traditional methods of flotation, agitation, or vat leaching. While it requires less energy, heap leaching raises certain environmental concerns as the release of toxic fluids into the surrounding environment can cause devastating effects. Engineering consultancies help mining companies construct and maintain facilities that maximize the benefits of the extraction process while complying with Nevada’s regulations as well as the Global Tailings Standard initiated in 2020.
Kappes, Cassiday & Associates (KCA) is a pioneer in precious metals heap leaching. According to CEO Daniel Kappes, the Bureau of Mines in Reno developed the process in the late 1960s, and KCA built its own technologies based off those developments. Its first US heap leaching project, based in Manhattan, Nevada, was only the third in the world of its kind. Today, KCA works primarily with exploration companies, providing laboratory testing and feasibility studies in addition to its engineering services. To date, its largest project was a contract for US$140 million to design and manage the construction of a 4,500 mt/d gold leaching plant.
Daniel Kappes, CEO of KCA says the process is not as easy as it looks. “Heap leaching sounds like a simple process, and people tend to think it simply involves piling rock up on a pad, sprinkling it, and waiting for the gold or silver to magically come out. In practice, the process is much more complex,” he said. “The key to heap leaching is the heap itself, so essentially, we advise our clients on how to prepare the ore and construct the heap so it stays uniformly permeable.”
As mines expand, producers will sometimes invest in upgrading their heap leach facilities as a means to boost production capacity. As a demonstration of magnitude, Coeur Mining awarded Canadian-based SNC-Lavalin a US$30 million contract to provide construction management at its Rochester mine. The plan calls for more than doubling the site’s annual crusher throughput to over 28 million tons, making it not only Coeur’s largest mine but also its biggest expansion project. A key component of the scale up is engineering a new heap leach pad. As operations continue to expand, it is expected that heap leaching facilities will only continue to grow.
Technological innovations drive growth
As mining techniques become more complex, engineering and consulting companies are implementing innovations to maximize efficiency. International mining consultancy firm SRK Consulting has been operating in Nevada for decades, but the resources it offers today are far more sophisticated than when the company opened in 1988 to assist with environmental and permitting-related projects. Now, corporate consultant Jeff Parshley describes the company’s most demanded services “involve helping clients with the necessary technical and scientific studies to support permitting or design.”
SRK Consulting uses 3D modeling software along with statistical and geostatistical methods to look at the structural setting and commodity distribution of ore deposits. In using datasets to better pinpoint targets, the company is able to improve the accuracy of operations at a given project. Parshley believes this software-enabled process allows producers to make their operations more airtight. In the context of global scarcity of gold and high gold prices, Kappes of KCA sees a need to improve gold recovery in order to make lower grade ores economically viable. He pointed to the need for innovation not only in hardware that makes it more inexpensive to process ore but also in software that ensures efficient process control. “For instance, in mining pits, blast hole locations are set by computers which then employ GPS technology to accurately position the drill, and the explosives are carefully tailored so that the rock does not spread very far,” he explained.
Mining Plus is another global mining services provider that believes that its utilization of technology is a differentiating factor: “One of the biggest added values of Mining Plus is that we focus primarily on design and engineering work through our extensive experience with computer modeling and our ability to efficiently evaluate these computer models for mine designs,” offered Manager – US, Scott Britton. The company has its own in-house Mining Knowledge Database that it implements in conjunction with its geological and geotechnical engineering skills to provide tailored results based on a project’s specific needs.
As the state that is home to the world’s largest gold mining complex, Nevada will always be a great testing ground for innovative technologies in precious metals production.
Image courtesy of Coeur Mining