Sheffield’s advanced-stage Moonlight Project involves the development of a well-defined copper porphyry deposit in north-central California. The Company’s long-term objective is to delineate a world-class underground resource. One that has the potential to host in excess of 400 million tonnes of 0.39%-0.5% copper with additional value-added silver and gold credits.
Additional tonnage is also known to exist in nearby smaller satellite deposits that are also located on the extensively-mineralized more than 9,000-acre Moonlight Property. They include two decommissioned copper mines which still benefit from under-developed mineral inventories that are still amenable to expansion and several known early stage copper prospects.
The Engel and Superior mines are where about 161.5 million pounds of copper, 23,000 ounces of gold and 1.9 million ounces of silver were recovered from 4.7 million tons of ore between 1914 and 1930. Notably, this was during an era that predated modern mining techniques – ones that translate into much better ore extraction recovery rates and more cost-effective mining production at depth.
Furthermore, the historically overlooked near-surface copper oxide resources at these Moonlight Project mines and prospects also appear to be particularly amenable to cost-efficient commercial development, and on an expedited basis.
In the near-term, Sheffield is strategically committed to the development of a high-grade, near-surface copper oxide resource at the former Engels mine site. With a targeted average grade of about 1.5% copper in a starter pit, this would involve the commercialization of a very cost-efficient open pit bulk tonnage mining operation involving in total a potential1-3 million tonnes from the Engels Mine. Additional shallow oxide copper tonnage known to exist in the Moonlight Deposit was previously estimated by Placer to consist of at least 12.2 millions tons averaging 0.54% copper. This historical resource has yet to be examined by a qualified person and determined to be NI43-101 compliant and hence should not be depended on.
Over the longer term, the favourable odds in support of the realization of a large tonnage, world-class polymetallic mineral asset at the Moonlight Deposit are further reinforced by the presence of robust infrastructure. This involves an on-site power supply, proximal water and the presence of paved roads that connect the property to a nearby highway.
This property is also in an economically under-developed rural region that is only 85 miles to the northwest of the city of Reno, which represents a logistically important service centre.
