Crown Mining Corp. [CWM-TSXV; CWMZF-OTC]] has announced results from initial metallurgical testing of mineralized samples from its Moonlight-Superior copper sulfide deposits in the Lights Creek Copper District in northeastern California. The metallurgical test work for the Moonlight deposit resulted in a copper recovery of 88% with a concentrate grade of 32.1% copper, the company said.
Crown controls approximately 15 square miles of patented and unpatented federal mining claims in the Light’s Creek Copper District in Plumas County. Its land position essentially covers an entire district that is known to contain substantial copper (silver), sulfide and copper oxide resources in three deposits – Moonlight, Superior and Engels, as well as several partially tested and untested exploration targets.
The Superior and Engels mines operated from about 1915 to 1930, producing over 161 million pounds of copper from over 4 million tons of rock, containing 2.2% copper as well as 1.9 million ounces of silver and 23,000 ounces of gold. Silver and gold made up almost 20% of the mined value at current commodity prices. The Moonlight deposit was discovered and drilled by previous operators during the 1960s.
The Moonlight-Superior Copper Project has a NI 43-101 compliant resource of over 2 billion pounds of copper, 750,000 ounces of gold, and 25 million ounces of silver. The property hosts four known copper deposits in a quartz monzonite intrusion known as the Lights Creek Stock. It covers an area of 18 km2. The company has said it is focused on advancing the project towards the production stage. It expects the permitting process to take less than three years once the process has begun.
Crown commissioned Dr. Corby Anderson, through Allihies Engineering Inc. in collaboration with Continental Metallurgical Services, to undertake an initial metallurgical evaluation of Crown’s copper (silver) deposits. The intention of the test program was to confirm effective flotation reagent conditions and demonstrate the recoveries and concentrate quality that can be achieved with the tested material.
The metallurgical report states that good recoveries and good grade concentrates are achievable with 90% of the grind passing 100 mesh with low reagent consumption. Additional testing will be required to determine optimum grind size and reagent mix. Mineralogical analysis identified chalcopyrite and bornite as the dominant copper minerals.
The report also noted the absence of iron sulfide (pyrite) in the samples as being advantageous in the flotation of the copper mineralization as well as potentially having other operational advantages. The report recommends that the next phase of testing will evaluate a regrind circuit which could enhance recoveries, particularly for the Superior deposit. These metallurgical results will be incorporated into the Preliminary Economic Assessment on the Moonlight deposit currently being prepared by Tetra Tech, Inc. of Vancouver.
Crown has said one of its objectives in 2018 is to partner with a copper producer. The company also said its deposit size and location will attract suitors in a recovering copper market.
Crown Mining shares advanced 6.7% or $0.015 to trade at 24 cents on Friday morning.