Bald Mountain

Overview

The Bald Mountain mine lies within the Southern Ruby Mountains of northeastern Nevada, approximately 110 kilometres northwest of Ely, Nevada and 110 kilometres southeast of Elko, Nevada.

Bald Mountain is an open-pit, run-of-mine, heap leach gold mine with conventional heap leaching technology and carbon absorption for ore treatment.

In 2011, Bald Mountain produced 93,000 ounces of gold at a total cash cost of $588 per ounce. Proven and probable mineral reserves as of December 31, 2010 was 5.1 million ounces of gold.

In February 2010, the federal Bureau of Land Management approved a planned expansion designed to significantly extend the mine life at Bald Mountain.

Location

The Bald Mountain mine lies within the Southern Ruby Mountains of northeastern Nevada, approximately 110 kilometres northwest of Ely, Nevada and 110 kilometres southeast of Elko, Nevada.

Nevada - 'snow covered' in Spanish - is a southwestern American state that was initially known for silver mining. Massive amounts of low grade gold deposits (Carlin-type ) were discovered starting with the 1960s and since then the state became the most important US producer. Nevada gold production from 1835 to 2008 amounts to a staggering 152 million ounces.

 The mine area as much of the state is characterized by an semi arid climate and scarce precipitations.

Geology and Mineralization

Bald Mountain represents the southern extension of the Carlin trend which is the largest gold-producing district in the United States.

Gold mineralization is associated within and surrounding a Jurassic quartz monzonite porphyry pluton and dike complex that intrudes Cambrian to Mississippian clastic and carbonate rocks.

Gold mineralization is associated with steeply-dipping structures and has been found to occur as lenses, veins and as micron-sized particles disseminated in both sedimentary and intrusive rocks. Alteration that accompanied the gold mineralization is represented by silificication, phyllic alteration and argillic alteration at shallow levels.

Several zones of economic mineralization or potentially economic mineralization have been identified namely, Top, Mahoney Canyon, Sage Flats, LJ Ridge and Mooney Basin. Gold as micron sized particles associated with steeply dipping structures in both sedimentary and intrusive rock. 

Subsequent alteration and weathering processes made the mineralization amenable to processing using the cyanide heap leach method.

Mining & Operation

Bald Mountain is a conventional truck and shovel open-pit, run-of-mine, heap leach gold mine with conventional heap leaching technology and carbon absorption for ore treatment.

A Thunderbird High Precision drill guidance system was implemented at the Bald Mountain operation.

Processing

Conventional crushing, heap leaching technology and carbon absorption for ore treatment.

Pads are constructed on 80-mil HDPE primary liners and have incorporated a pad leak detection system and over 6 inches of low permeability compacted soil liner which is underlying the primary liner. Pregnant solutions report to the pregnant ponds from where it is pumped to the adsorption, desorption and recovery plants.  The pregnant ponds are lined with an 80mil HDPE primary liner and a 40 mil HDPE secondary liner placed over prepared native soil subgrade. Pregnant soluitons are pumped to the carbon columns where it counterflows on activated carbon. Loaded carbon is then stripped and refined. Barren solutions are being added sodium cyanide and then are returned to the heap leach pad.

Power is brought to the mine site via a 17 mile 69KVA power line from the Alligator Ridge Mine substation.

Water is pumped from wells located on company's mining property.

Environment & Community

Bald Mountain mine is certified under the ICMI Cyanide Code.

All mining facilities are designed to produce zero discharge.

All Barrick's Nevada mining operations take great care in protecting bird species that might nest in the area during the spring and summer months - during the nesting season the mines do not create any new disturbances.

More than 90 km of riparian habitat have been restored in Nevada near the company's mining projects.