|Stage: ||Residual Leaching, New Mining and Leaching and Exploration |
|Location: ||Near Lovelock (West-Central Nevada, USA) |
|Type: ||Surface Mine |
|Metals: ||Silver and Gold |
|Product: ||Doré |
|Ownership: ||100% |
|Land position: ||+8,800 acres (35.5 square kilometers) |
|Production: ||2012 = 2.8M oz Ag and 38,066 oz Au |
|Cash operating costs1: ||2012 = $9.62/Ag oz |
|Proven and probable reserves2: ||44.9M oz Ag and 308,000 oz Au |
|Measured and indicated resources2: ||120.7M oz Ag and 865,000 oz Au |
|Inferred resources2: ||27.2M oz Ag and 123,000 oz Au |
|Employees: ||+200 |
The Rochester mine and associated heap leach facilities is a surface silver and gold mine, located in Pershing County, Nevada. The mine is accessed by approximately 25 miles of paved and all-weather gravel road northeast of the town of Lovelock. The Company owns 100% of the Rochester mine through its wholly-owned subsidiary, Coeur Rochester, Inc. (“Coeur Rochester”), subject to royalty provisions to former owner ASARCO. The mine consists of the main Rochester deposit and the adjacent Nevada Packard deposit, located three miles south of the Rochester mine.
The Rochester mine is fully supported with electricity, supplied by a local power company on its public grid, telephone and radio communications, production water wells, and processing, maintenance, warehouse and office facilities.
The mine utilizes the heap leaching process to extract both silver and gold from ore mined using conventional surface mining methods. Gold and silver are recovered by leaching of crushed ore placed on pads located east of the Rochester pit. Based upon actual operating experience and metallurgical testing, the Company estimates ultimate recovery rates from the crushed ore of between 59.0% and 63.0% for silver, depending on the ore being leached, and 93.0% for gold.
There is an ongoing legal dispute over unpatented federal mining claims at Rochester, as more fully described in Coeur’s quarterly and annual reports on Form 10-Q, Form 10-K and other filings with the SEC.
Geology and Exploration Potential
At Rochester, silver and gold mineralization is hosted in folded and faulted volcanic rocks of the Rochester Formation and overlying Weaver Formation. Silver and gold, consisting of silver sulfosalt minerals, argentite, silver-bearing tetrahedrite and minor native gold, are contained in zones of multiple quartz veins, veinlets and stockworks with variable amounts of pyrite.
The Company commenced studies to investigate the potential to recommence mining and leaching of new material in 2008 and completed feasibility studies in 2009 and 2010 demonstrating the viability of an expansion of mining and leaching operations at its Rochester mine through 2017. The Company prepared an Amended Plan of Operations for resumption of mining within the existing and permitted Rochester pit and construction of an additional heap leach pad, all within the currently permitted mine boundary. The Bureau of Land Management (BLM) deemed this plan complete in August 2009 under federal regulations and initiated the National Environmental Policy Act process. The BLM issued a positive Decision Record (DR) for the mine to extend silver and gold mining operations by several years with new production ounces being recovered in the fourth quarter of 2011.
In 2012, exploration expenditures of $3.9 million funded 138,121 feet (42,099 meters) of reverse circulation, vibratory rotary (Sonic) and core drilling. The 2013 budget for exploration is $3.5 million.
In 2012, Rochester ramped up silver and gold production in its first full year of production from the approximately 50-million ton new heap leach pad.
2013 production at Rochester is expected to be 4.5 to 4.9 million ounces of silver and 44,000 to 46,000 ounces of gold. Rochester's proven and probable reserves measured 44.9 million ounces of silver and 308,000 ounces of gold at year-end 2012. Measured and indicated resources totaled 120.7 million ounces of silver and 865,800 ounces of gold, in addition to inferred resources of 27.2 million ounces of silver and 123,000 ounces of gold. Estimates of measured and indicated resources may differ from the amounts presented here for the reasons set forth in the endnotes found at the bottom of the Reserves and Resources tables.
Please refer to the latest quarterly financial results news release for updated operational guidance.