Van Dyke is an in situ copper recovery project (ISCR) located in the US state of Arizona. The project is in the development stage.
Desert Fox Van Dyke, a wholly owned subsidiary of Copper Fox Metals, is the 100% owner of the project.
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Historical mining at the location between 1929 and 1945 produced 11.8 million pounds (mlbs) of 5% copper (Cu). The mine also produced 4mlbs of Cu between 1988-1989 utilising an In-situ Recovery Project (ISCR) method.
In January 2021, Copper Fox Metals reported an independent Preliminary Economic Assessment (PEA) of Van Dyke developed in accordance with National Instrument 43-101 (NI 43-101).
Over an estimated mine life of 17 years, Van Dyke is expected to produce 1.1 billion pounds of copper with peak production of 85mlbs annually.
A 2020 PEA Report reported a post-tax net present value (NPV) of $645m and an Internal Rate of return (IRR) of 43.4%, at $3.15/lb of copper price.
The project’s pre-application phase is expected to take around 2-3 years, which will be followed by an up to two-year permitting process after the submission of necessary applications.
Location and site details
Van Dyke is located within the Miami- Inspiration trend of porphyry deposits in the Globe-Miami Mining District, Gila County, east-central Arizona. The site is around 110km east of Phoenix.
The project covers 531.5ha of mineral rights and 5.75 of surface rights. It includes 26 patented parcels of mineral estate lands and 35 unpatented lode mining claims.
Key infrastructure from earlier activities that still remains at the site include a copper cementation plant, Van Dyke Shaft, access roads, equipment laydown areas, drill sites and steel drillhole collars and other ancillary facilities.
History
Exploration activity at Van Dyke dates back to 1916 when the first hole (V-1) on the property was drilled. In 1919, Van Dyke Copper Co. (VDCC) started excavating the vertical Van Dyke shaft which intersected mineralisation.
However, further development was suspended due to low copper prices.
The first ore shipments began in 1929 and continued to 1931. The project then operated between 1943 and 1945 while drilling activities were conducted in the 1970s.
In 1976, Occidental initiated in-situ leaching or in-situ copper recovery (ISCR) programme in the west of the Van Dyke shaft.
Kocide Chemical Corporation (Kocide) entered into a deal with Van Dyke in 1986 for developing ISCR and copper recovery operation in Occidental’s test area.
In 2012, Bell Copper Corporation (Bell) entered into a power and sale agreement with Bennu Properties and then Copper Fox signed a purchase agreement with Bell to acquire 100% interest in the project.
Six PQ diameter diamond drill holes were completed in 2014 by Copper Fox and it filed a NI-43-101 Technical Report on 18 November 2015.
Geology and Mineralisation
The Van Dyke Copper Project is situated in the Basin and Range province of east-central Arizona, which underwent considerable deformation that started in the Palaeoproterozoic and continued through to the Tertiary.
The property is situated within the Globe-Miami mining district featuring igneous, sedimentary, and metamorphic rocks of Precambrian, Paleozoic, Tertiary, and Quaternary age.
The Miami-Inspiration trend of deposits has five main orebodies- Live Oak, Thornton, Miami Caved, Copper Cities and Miami East.
The mineral deposit is primarily secondary or supergene copper deposit tied to well developed porphyry copper systems. Malachite, azurite, chrysocolla and chalcocite are the main copper-bearing minerals.
Mineral resource estimates
Van Dyke Project’s resource estimate includes 97,637 kilo tonnes, grading at 0.33% total copper, 0.23% acid soluble copper, 0.04% cyanide soluble copper and 0.24% recoverable copper in the indicated category.
The figure stands at 168,026 kilo tonnes grading at 0.27% total copper, 0.17% acid soluble copper, 0.04% cyanide soluble copper and 0.19% recoverable copper in the inferred category.
Mining
Studies showed that in-situ wellfield from underground development will be more cost effective compared to surface mining. Underground development will be completed by conventional drill and blast tunnelling techniques.
In the first phase of underground development, the main access ramp, ventilation and access to the historic Van Dyke shaft, the north decline for access above the deposit along with the galleries connecting to the decline will be installed.
The second phase of development will involve the south decline, the galleries for well installation associated with the second phase, and the ventilation and egress way to the ventilation and egress raise.
In-situ copper recovery (ISCR) process is suitable for copper extraction at Van Dyke.
The ISCR or ISL is a leach extraction process where barren leach reagent is injected into the orebody through injection wells which results in in-situ leach reaction.
Pregnant solutions (PLS) with leached copper is extracted through recovery wells. Copper is produced onsite by conventional solvent extraction (SX) and Electrowinning (EW).
Infrastructure
Sewer, water, communications, and powerlines exist at the site.
The planned infrastructure includes administration, maintenance, warehouse facilities and processing facilities which include solvent extraction and water treatment plants, administration offices, ancillary facilities with warehouses and maintenance shop, electrowinning tank house and tank farm for auxiliary vessels, and solution pond for handling among others.
Contractors
The NI 43-101 Preliminary Economic Assessment Technical Report for the Van Dyke Copper Project was prepared by Moose Mountain Technical Services (MMTS) and Ausenco.
On 17 August 2021, Copper Fox Metals announced that it retained water resource consulting firm Montgomery & Associates for completing a data gap analysis of the Van Dyke oxide copper project.
Montgomery and Associates was also involved in the development of a Conceptual Hydrogeological Model for the project. It also completed an Order of Magnitude (+/-30%) estimate of the timeline, costs and data/surveys required for completing the hydrogeological portion of the pre-application and formal permitting process for the project.
In April 2022, Ausenco Engineering Canada was retained to provide process and hydrogeological services for the copper project. The company was also contracted for technical supervision for Phase one activities.
On 8 September 2022, Copper Fox Metals announced the results of an early-stage Biological Evaluation (BE) of some parts of the Van Dyke Project prepared by WestLand Engineering & Environmental Services.
