Millrock Resources (CVE:MRO) said on Monday it has recommenced drilling at the Galiuro project, in Arizona.
The junior miner gained 4 cents, or 10.13 percent, to reach 43.5 cents a share on Toronto’s junior venture exchange.
Vale Exploration Canada, a wholly-owned subsidiary of Vale S.A, and the world’s second largest metals and mining company by market capitalization, is funding the work as part of its earn-in agreement signed back in 2009.
Millrock said it plans to focus on the four mile target where a circular magnetic feature ringed by a strong conductive zone identified by an airborne geophysical survey will be targeted.
The company has pre-collared the hole to a depth of 453 metres using a reverse circulation drill. At 427 metres, Millrock identified leach cap rocks with andesite and quartz porphyritic intrusive rocks through drill cuttings.
The leach cap indicates possible proximity to a porphyry copper deposit, Millrock said in a statement.
Depending on results, the hole may be drilled to a depth of 2,000 metres. Meanwhile, a second hole may be drilled contingent upon results and budget.
Prior drilling by Millrock and Vale resulted in the discovery of porphyry copper mineralization and alteration in Cretaceous-aged rocks hidden beneath Tertiary volcanic cover rocks.
Vale, headquartered in Brazil, can earn a 60 percent stake in the project if it spends $3.5 million on exploration and makes cash payments worth $850,000.
Following the completion of the drill program, Vale will be in the position to exercise its option if it makes the remaining cash payments, and could boost its stake to 70 percent if it funds a feasibility study.
The Galiuro project is made up of 366 federal mining claims and 18 Arizona State prospective permits covering about 6,800-hectares, and is located near the San Manuel and copper district in southeastern Arizona.
Millrock currently has 12 active exploration projects, eight gold-copper properties in Alaska, and four porphyry copper prospects in Arizona.