First Cobalt’s vision for the Cobalt Camp is to revisit historic mines and cobalt-rich mineral occurrences, some of which have not seen meaningful exploration activity in more than 75 years, and evaluate the opportunity to use modern geoscience and bulk mining techniques to revive this historic world-class silver camp by targeting its cobalt potential.
The Keeley and Frontier Mines were originally developed and operated as separate mines and eventually integrated in 1961. From 1908 to 1965, the Keeley-Frontier Mine produced a total of over 3.3 million pounds of cobalt at a recovered grade of 0.5% and 19.1 million ounces of silver at a recovered grade of 58 ounces per tonne using these reported production numbers. Most of the production occurred between 1922 and 1931. The Company acquired a 100% option over the property in March of 2017.
Consolidation of the property has recently included the historic Bellellen Mine, adjacent to Keeley-Frontier, which is particularly enriched in cobalt and nickel. Silver was extracted in the first year of mining, then largely exploited for cobalt and nickel. Grades and tonnage were not reported, but in 1943, it was reported that over 12 tons of ore were shipped with an average grade of 9.25% cobalt and 11.55% nickel. Combined, these mineralizing systems represent over two kilometres of strike length of near surface size potential for open pit mining.
The neighbouring towns of Silver Centre and Cobalt, Ontario, together called the Cobalt Camp, were historically the most prolific cobalt jurisdictions in Canada and the largest silver producers worldwide. It is estimated that from 1904 to 1985 this mining camp produced 50 million pounds of cobalt and 600 million ounces of silver from 70 different mines.
Keeley-Frontier Drill Program
The drilling program has been designed to test several areas known to be cobalt-rich over the two kilometre strike length of the Keeley-Frontier vein system, including Haileybury and Bellellen (Figure 1). Over 30 drill holes have been planned that range from 30 to 300m depths to establish variable vein orientations and to determine the Co-Ni-Ag grades in the host rocks to the known Ag-Co calcite veins. Aside from some surface grab samples for validation, very few cobalt grades are known from these areas. To account for this, drill spacing at each area will typically be 25 meters. Based on results, continuity and strike extent of the Co-rich vein systems will be followed up later in this drill program.
Drilling began on August 8 at the Haileybury Vein with a sequence of eight diamond drill holes testing various vein sets mapped in outcrop. The Frontier#1 and the Keeley #1 and #2 Veins are also Co-rich and will be tested subsequently. Holes of 250m length will test the Keeley 820 area where underground Co-Ni assays mark an undeveloped vein system. The area around the Woods and Watson Veins will also be tested with shallow holes, typically less than 50m, to determine if cobalt mineralization occurs as a halo to these Ag-rich systems. Deeper targets as part of the Keeley-Frontier Extension to the north and along the Beaver Creek Fault to the west will be tested after this first stage of drilling.
Sampling will be done on all drillholes for multi-element geochemical analyses including all metals of interest: cobalt, silver, nickel, bismuth, copper, gold, and zinc. Select drillholes will be surveyed for magnetic susceptibility, conductivity and resistivity to identify potential extensions of mineralization that may have been intersected in the hole.
The Cobalt Camp occurs within the Cobalt Embayment consisting of Proterozoic sedimentary rocks unconformably overlain on Archean metavolcanic and metasedimentary rocks that have been intruded by the Nipissing diabase sills, dated at approximately 2.22 billion years. The Proterozoic sedimentary rocks are largely sequences of sandstone, arkose and conglomerate with minor dolomitic units collectively known as the Huronian Supergroup. The overall setting of the Cobalt Embayment is that of a continental rift system.
Mineralization occurs as Ag-Co-Ni-Bi-arsenides predominantly hosted in veins and stockworks known as Five-Element Vein Type deposits. Veins and stockworks are concentrated within and near the contacts of Nipissing Diabase dykes with Huronian Supergroup metasedimentary rocks as well as Archean metavolcanic rocks. Zoning of the metals within the individual deposits have not been documented.
The genesis of mineralization is contentious, but the proximity of veining to the intrusive contact between the Nipissing Diabase sills and either the sedimentary or the volcanic rocks may suggest structural contrast between the rock types is a major factor to the distribution of veining. It seems unlikely the sills provided a heat source to drive hydrothermal fluid flow as many vein systems have developed within the sills showing brittle deformation textures. The unconformity between the volcanic rocks and the younger sedimentary rocks may have been an important conduit for metals in the silver-rich vein systems. The genetic relationships between cobalt-rich and silver-rich veins systems is currently unknown.