For over 100 years, cyanide, now managed under the International Cyanide Code, has been the leaching reagent of choice in gold mining because of its high gold recoveries, robustness, relatively low costs and safety when handled properly. Nonetheless, cyanide remains a controversial issue in environmental assessments and permitting processes due largely to public perception and entrenched viewpoints. Cyanide, banned in some jurisdictions, has an ongoing public relations problem and associated cost for the gold mining industry due to the environmental impacts and its potential for lethal effects on human, animal and aquatic life resulting from its possible mismanagement. This has fueled research aimed at identifying and developing less toxic leaching agents to recover gold.
In Place Mining (in-situ recovery) combined with the Envirometal solution which uses FDA approved elements that are essential elements to human offers alternative environmentally friendly technology to conventional mining.
The concept of IPME is a clearly preferable concept to conventional open pit or underground mining in that little surface disturbance occurs, the need for conventional large scale plants and equipment is reduced or eliminated, the permitting cycle for a mining project will be shortened and the ultimate reclamation and restoration of the land and water will be quicker and more efficient. In-Situ-Recovery (ISR) is the most advanced and effective means of IPME.
Group 11 Technologies is working to revolutionize the concept of environmentally-friendly mineral extraction by combining two proven technologies: In-Situ Recovery (“ISR”) and eco-friendly, water-based chemistry. This non-invasive method allows for the extraction of valuable minerals directly from the ground—without traditional open-pit or underground mining. The result is a cleaner, safer, and more sustainable solution that dramatically reduces environmental impact while remaining economically viable.
ISR is an environmentally friendly process by which uranium, gold, copper and other minerals can be extracted from the ground with minimal disturbance to the surface environment. ISR has a long history, starting with uranium extraction in the 1960s. Since then, ISR technology has evolved significantly and accounts for about 70% of global uranium production today. Dr. Dennis Stover, an earlier inventor and pioneer in the commercialization of ISR technology, and a Group 11 and enCore Energy Board Member, has a wealth of knowledge of all aspects of uranium ISR methods and hold patents relating to the process.
In ISR mining of uranium, uranium is dissolved by solvents containing either sulfuric acid (Kazakhstan, Australia, etc.) or Sodium Bicarbonate (Baking Soda has replaced the use of acid in the United States ISR uranium industry). In ISR mining of copper oxide ores, the dissolving solution is usually sulfuric acid. The ISR mining of gold uses Group 11’s proprietary and eco-friendly lixiviant or solution to dissolve the gold.
Boreholes or “delivery wells” are drilled into an orebody, through which a dilute solution is pumped to dissolve the target minerals or metals. The solution moves through the rock in a controlled manner to nearby recovery wells, where it is pumped back to the surface for processing. Differential pumping rates or natural impermeable barriers are used to control the movement of the solution through the rock. This, combined with well field design, prevent any solution from exiting the mine area. The pumping action of the recovery wells ensures all of the mineral-rich or “pregnant solution” is collected from the delivery well.
This technology is applicable to a broad spectrum of essential minerals and metals ranging from base metals to industrial minerals to clean energy fuel to precious metals.
ISR for uranium extraction has been a well-established and commercially proven method since its inception. However, despite its long history of success, the technology has seen limited advancements over the past 50 years, presenting opportunities for innovation to enhance its efficiency and sustainability.
ISR is a highly effective method for extracting uranium from sandstone-hosted deposits, typically employing oxygenated water and baking soda as a lixiviant. However, there are certain limitations that, if addressed, could improve the process. For instance, several promising domestic uranium deposits have been identified where insufficient water pressure prevents the necessary dissolved oxygen content for current ISR extraction.
Where ISR is not feasible, Group 11’s leaching technology may replace conventional milling with mine site heap leaching and mineral recovery using environmentally benign chemicals making remediation of mine waste a short-term task with the cleaned waste suitable for return to the natural environment with no long-term impacts.
Group 11’s proprietary liquid oxidant shows potential for effectively working with uranium deposits in low water pressure environments, as well as those found in dry formations. However, further testing is needed to fully confirm its capabilities.
ISR for gold has been proven successful at the lab scale using environmentally friendly chemistry as an alternative to cyanide leaching. It has shown promise in gold deposits with specific characteristics which allow the leaching solution to flow through the ore.
Until Group 11, there was no leach solution or lixiviant that could dissolve gold in a safe and environmentally friendly manner. The recent introduction of our proprietary eco-friendly and safe process has only now opened the door to the advanced research of the in-situ recovery of gold from underground deposits.
Group 11 has worked towards discovering more eco friendly methods of gold extraction by using a water-based solution with SRUs, eliminating the need for traditional cyanide-based leaching. This method has been tested at a lab scale with the first test project showing success.
Our goal is to refine and perfect this water-based technology through specific testing, ensuring the efficiency and sustainability in diverse conditions. The next steps focus on securing fresh core material to test the solvent’s effectiveness and its suitability for In-Situ Recovery.
Pilot-scale testing has been conducted to assess the viability of ISR for copper and vanadium extraction. Some early-stage testing has also been explored on rare earth elements but is still considered experimental in the western world. Further research is needed to optimize the process for large-scale commercial applications.
Building on the promising success of using ISR and environmentally friendly solutions for uranium and gold, Group 11 plans to expand and optimize this technology to extract other elements.
Ability to process sulphide concentrates onsite, without need for a cyanide permit
Superior return both socially and economically for the operator
Ability to deploy a mobile unit to re-process existing tailings or waste rock piles that not only cleans up previous liabilities but also provides cash flow generation
Can process ‘black sands’ produced from placer mining operations, which are unable to be recovered due to the fine particle size of the free-gold
Opportunity to work with environmental management groups to remediate projects.
Enhances social benefit for restart of mining operations by cleaning up existing disturbances
Several jurisdictions either have outright cyanide bans or effective cyanide bans due to lack of social license
The combination of scalable equipment combined with reduced permitting hurdles makes small-scale production, including bulk samples, commercially viable