Technology
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.
Development of In Place Mineral Extraction (IPME) through In-Situ-Recovery (ISR) of Metals
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.
Non-Invasive Mineral Extraction Technology
What is In-Situ Recovery (ISR)?
Advantages to In-Situ Recovery Mining:
- Significantly lower capital and operating costs
- Reduced mine development time
- Unlocks the value of smaller deposits
- No waste or ore moved
- No creation of open holes, waste dumps, leach pads or tailings
- Minimal visual disturbance
- Minimal noise, dust, and greenhouse gas impact
- Fewer permits are required compared to other mining processes
- Reduced mine remediation time and costs
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 mining 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. The enCore Energy team, led by Dr. Dennis Stover, an earlier inventor and pioneer in the commercialization of ISR technology, have 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.
Our Technology: ISR Uranium
A major limitation of the ISR used for uranium extraction globally is the need for substantial water pressure to keep the dissolved oxygen in solution to yield economic quantities of uranium. A number of otherwise amenable domestic uranium deposits have been identified wherein there is insufficient water pressure to achieve the necessary dissolved oxygen content. This is where Group 11 Technologies comes in. Recent laboratory studies utilizing Group 11’s proprietary liquid oxidant have suggested that this oxidant may work on these low water pressure uranium deposits as well as those hosted in dry formations including breccia pipes and many other conventional deposits. This environmentally benign liquid is effective at neutral or slightly alkaline conditions consistent with natural ground water conditions. Verification of this potential would increase the recoverable domestic uranium resource at a time when US utilities have found themselves dependent on Russian and Russian-China controlled sources for the essential fuel to power domestic carbon free nuclear electric power plants.
Currently, many uranium deposits are subject to conventional mining and milling which employs harsh, environmentally adverse chemicals such as strong acids with resulting airborne emissions, acidic mill tailings, and long-term residual environmental impacts. 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. Laboratory and pilot testing of Group 11’s proprietary liquid oxidant has shown its potential as an alternative to conventional milling providing a far more environmentally friendly extraction process for many minerals and metals that are essential to Clean Energy solutions including batteries for EVs, and nuclear electricity generation.
This technology is applicable to a broad spectrum of essential minerals and metals ranging from base metals (copper, nickel) to industrial minerals (cobalt, rare earths) to clean energy fuel (uranium) as well as precious metals (gold, silver).
ISR Gold Recovery
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.
Our unique, environmentally safe solution, is water-based and only includes ingredients approved by the FDA for human consumption, our solution is fast and offers comparable leach kinetics to that of high-intensity cyanide, assuring high recovery rates.
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 our solution which uses FDA approved elements that are essential elements to human offers alternative environmentally friendly technology to conventional mining.
ISR mining of gold is in its infancy with the first ISR of gold being unintentional, resulting from cyanide seepage from an above-ground tailings impoundment into the ground and subsequently into low-grade gold stopes in a mine in the Northwest Territories in Canada. The water, containing trace amounts of gold, was pumped from the workings and used as process water in the mill resulting in slightly higher gold recoveries.
The first planned ISR operation was to be conducted in Victoria, Australia in the early 1980s. The plan envisioned the injection of alkaline cyanide solution into a deep porous paleo-placer channel. Following initial pump and dye testing, amid public and governmental concern about potential groundwater contamination in the farming area, the project was shelved.
All successful gold ISR projects to date have been in other parts of the world, all have used cyanide, with the first successful test of gold ISR at the Gagarskoye Gold Mine. An early and apparent first test of non-cyanide ISR was conducted at the Ajax mine in Cripple Creek, Colorado by the Golden Cycle company in the 1970’s.
By utilizing Group 11’s proprietary environmentally superior solvent in combination with enCore’s deep expertise in ISR, Group 11 believes that it has the combination to reshape the traditional gold mining industry through In Place Mineral Extraction.
The development of In Place Mineral Extraction (IPME) through ISR 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.
ISR Copper Recovery
Uranium is not the only metal to be recovered historically by ISR. Several copper ISR projects have operated principally since the 1970’s in the U. S., Chile, Russia, Zambia, Cuba and Australia with overall good results. Primitive ISR copper recovery dates back several thousand years in China. All known copper ISR operations use, or plan to use, acid based lixiviants (liquid solvents). There are currently three active copper ISR projects in the U. S. ranging from the permitting stage to post-pilot operational stage. Excelsior Mining (MIN-TSXV) has the advanced Gunnison project, Copper Fox (CUU-TSXV) has the planned underground ISR Van Dyke project and Taseko Mines (TKO-TSX) has the operational Florence project. All are located in Arizona.
Test Projects
Under Construction
Concentrate Pressing
Ability to process sulphide concentrates onsite, without need for a cyanide permit
Superior return both socially and economically for the operator
Waste and Tailing Re-Processing
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
Placer ‘black sands’
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
Remediation
Opportunity to work with environmental management groups to remediate projects.
Enhances social benefit for restart of mining operations by cleaning up existing disturbances
Environmentally & Socially Aware Jurisdictions
Several jurisdictions either have outright cyanide bans or effective cyanide bans due to lack of social license
Small Scale Production
The combination of scalable equipment combined with reduced permitting hurdles makes small-scale production, including bulk samples, commercially viable
