Engineering and Mining Contractors
Increasing precious metals recovery offers critical opportunities elsewhere
Few places can compete with Nevada when it comes to enhancing gold recovery. In the context of declining grades and harder-to-find deposits, gold ores in the past decade have been the subject of several investigations and research studies aimed at enhancing recovery and improving leaching kinetics. Based in Reno, Daniel Kappes, president, and CEO of Kappes, Cassiday & Associates (KCA), pioneered its heap-leaching expertise almost 50 years ago and has since contributed to Nevada’s engineering radiation worldwide, while consistently coming up with new technologies to advance metallurgic test work and recover more gold.
Celebrating its 50th anniversary, KCA is not done leading engineering feats for the benefit of Nevadan and global majors and juniors. The firm, which specializes in laboratory testing, engineering designs, feasibility studies, and field construction and management, was notably contracted by Agnico Eagle at the Pinos Altos mine in Mexico, on a US$140 million contract for a mill/heap leach feasibility study. Nevada remains KCA’s main US market, with more than 30 projects across the state.
A core question for precious metals mines to answer is that of optimizing recovery. Until a couple of decades ago, a recovery rate of 3 g/t Au would have been considered low-grade, and perhaps not economically viable. In today’s context, majors need to adapt and leverage technologies that make 1 g/t Au deposits worth considering. A Nevada-born innovation is changing the picture of recovery: KCA’s Carbon Converter. Dan Kappes explained his innovation: “It allows clients to turn their carbon fines and used carbon into a product they can leach, or smelt directly, to produce gold/silver bullion. The Carbon Converter can treat wet and dirty carbon fines, turning “trash” carbon into a valuable resource, and has demonstrated a gold and silver recovery of up to 99% in operation.”
At the exploration stage, an early investment in engineering abilities can fundamentally impact the outcome of a feasibility study and the project’s appeal to investors. Viva Gold contracted KCA to carry out a metallurgical optimization program at the firm’s Tonopah gold project. KCA used a technique called pulp agglomeration and heap leach testing, which yielded results beyond initial estimations for gold recovery: “The test work showed that the yield was 91%, while the yield with an RPA at the same grade was 70%. For very little additional capital we can increase the gold recovery by about 20%”, explained James Hesketh, CEO of Viva Gold. “The 91% indicated recovery is significantly higher than the 71% recovery estimate utilized in the 2022 PEA Technical Report” he concluded.
"With the boom in lithium down in the Tonopah region, we have seen our activity increase to about a half dozen projects in the state and have a dedicated group that focuses on brine mining for lithium projects."
Jay Nopola, Senior Vice President Mining and Energy, Respec
Resource nationalism driving demand
Geopolitical turmoil, global supply chain disruptions, and environmental standards have all highlighted the importance to mine domestically rather than abroad. In Nevada, the unfolding lithium story is driving growth for consulting and engineering firms that are seeing a bigger part of their mining-related expertise being focused on “white oil” projects. The extensive talent available in Nevada means firms can rely on expertise from the permitting stage to closure, with key innovations along the way. Widely recognized as a leading engineering consultancy in open pit and underground mine design, planning, and engineering, SRK Consulting saw growing demand at the permitting stage for several new and ongoing lithium projects in Nevada, notably Lithium Americas’ Thacker Pass - along with Albemarle’s Silver Peak operation.
The growing demand for lithium-related engineering expertise due to the recent boom in discoveries in Nevada has attracted several engineering firms from outside state borders. Respec, a South Dakota-based engineering consultancy with leading technology-related services, rode the lithium wave and saw its activity surge to half a dozen projects in Nevada in 2022, with a dedicated brine mining group. The firm partnered with lithium explorer Pan American Energy Corp. to design and execute a maiden drill program at the Horizon project in Tonopah. In October, ABTC engaged Respec to perform an independent analysis of exploration results at the Tonopah Flats project, which benefited from a DOE grant, and to generate and issue an SK-1300 compliant Inferred Resource report.
Out of Utah, Millcreek Engineering carries out process work and basic engineering for lithium processes. Once the projects advance through several stages of construction, Kevin Martindale, director of business development, noted a growing demand for augmented reality (AR) capabilities, as AR-powered programs render mining clients’ plant designs more actionable. “We will take clients through an AR-type walkthrough: We put them in a room, give them 3D goggles, and they get to walk through the plant themselves. Clients can then see potential constructability issues and construction advancements”, he explained.
MMR Constructor, an electrical instrumentation contractor, saw its mining share grow in the past years. Having worked with NGM and Freeport McMoRan, the firm eyes growth opportunities in the sector. Resource nationalism means engineers and contractors will see growing demand for their services in the coming years, as put by MMR Constructors' west coast division district manager Darryl Sockwell: “For security, stability and independence reasons, projects that large operators were going to develop internationally are now being considered in the US. This will be a long-term trend: We have already been approached about expansion projects to take place in 2023 and beyond.”
Image courtesy of Kappes, Cassiday & Associates (KCA)