Rock Creek Mine

Overview

The Rock Creek Mine and Mill complex consists of two open pit gold mines (Rock Creek and Big Hurrah), and the Rock Creek Mill, where gold is recovered through density and cyanide vat leaching processes. Rock Creek is operated by the Alaska Gold Company, a wholly owned subsidiary of NovaGold Resources, Inc.

Location

The Rock Creek Mine and Mill complex is located about 6 miles north of Nome, on the Seward Peninsula (click here for map). The mine and mill are situated on private land owned by the Bering Straits Native Corporation and the Alaska Gold Company in the Snake River Watershed. The Big Hurrah mine site is located about 40 miles from the Rock Creek site, and about 42 miles east from Nome; it is situated on land owned by the Alaska Gold Company in the Solomon River watershed.

Type of Ore and Production

Both the Rock Creek and the Big Hurrah deposits are within the Mixed Unit of the Nome Group. 65% of the gold at Rock Creek is contained in tension veins, with the rest in Albion Shear, primarily in quartz veins. Gold at the Big Hurrah mine is within quartz veins located in fault zones.

The Rock Creek Mine site includes an open pit gold mine, two non-acid generating development rock stockpiles, a gold recovery plant, and a paste tailing storage facility. The projected length of the Rock Creek mine is 4.5 years; the mine will operate seven days a week, year-round. Mining in the Walsh Zone pit and the Main pit occurred in 2008, and mining was done using the drilling and blasting techniques. Mining produced both development rock, primarily used to construct the tailings dam and ore rock.

The planned mining facilities for the Big Hurrah site include an open pit gold mine, an acid generating and a non-acid generating rock stockpile, an ore stockpile, and administrative facilities (truck maintenance shop, fuel and explosive storage, and administration building). Ore from Big Hurrah will be hauled via 100 ton haul trucks to the Rock Creek Mill complex for milling. The expected life of the mine is 4 years. Mining operations at Big Hurrah will occur for 3-6 months of the year, with trucking occurring year round.

At the Rock Creek site, 100,000 tons of ore and 1.9 million tons of development rock was mined. In 2008, the activities at the Big Hurrah site included drilling water well drilling and conducting pump tests.

Operation

Ore from the two mines will be processed at the Rock Creek Mill facility, at an expected rate of 2.5 MT per year. Processing begins with crushing of the ore first in a jaw crusher (for material over 4 inches) and then in a cone crusher (once all material is smaller than 4 inches). From there, the ore is ground in a ball mill crusher, and water is added form a slurry. This slurry is sent through a gravity circuit, where 75% of the gold will be recovered. Tailing from the gravity circuit is sent through a flash froth flotation circuit and subjected to cyanide vat leaching in the leach carbon pulp recovery circuit. Recovered gold from the gravity circuit and the leaching circuit is combined and poured into dore bars. The tailings from the milling are combined with the cyanide from the cyanide leaching, and then processed into paste and deposited into the tailing storage facility.

Current Status of the Project

Mine and Mill Temporary Closure

The mill began operating on September 18, 2008, but shut down on October 9th due to machinery failure. The mill resumed operations again on November 12th, but on November 24th, NovaGold decided to temporarily shut down the project for an indeterminate length of time to address issues with the crushing system. Rock Creek is currently operating under a Temporary Closure/Care and Maintenance Plan. During this closure period, facilities will be maintained, and monitoring activity required by the various permits will continue. The Clean Water and Mining Program Director is in frequent contact with representatives from the Large Mine Permitting Team at DNR to ensure that the mine facility continues to meet permit standards during the closure period.

Storm Water Management Issues

Following inspections in the spring and summer of 2007, the Alaska Department of Environmental Conservation (DEC) issued Alaska Gold Company a Notice of Violation on February 19, 2008, formally notifying Alaska Gold Company of its violations of turbidity limits in stormwater run-off into Rock Creek. During a follow-up inspection in the late spring of 2008, DEC again found Rock Creek in violation turbidity standards, leading DEC to issue another Notice of Violation on June 6, 2008. Rock Creek’s failure to implement mitigation measures required by DEC to address the turbidity violations resulted in the issuance of a Notice of Noncompliance with permit conditions by the U.S. Army Corps of Engineers on December 9, 2008. As a result of Rock Creek’s violations and failure to remedy the problem, Alaska Gold Company agreed to pay a fine of $883,628 imposed by the federal government.

Wastewater Issues

Rock Creek is currently looking for ways to deal with its wastewater. Rock Creek obtained a permit to construct 15 Underground Injection Control (UIC) wells in 2008. Wastewater from the tailings pond will be treated at the water treatment plant, and then injected into the underground wells, as permitted under WMP Permit Number 2003-DB0051. In 2009, Rock Creek submitted a minor modification permit application to drill 15 additional UIC wells for wastewater disposal, and the permit was granted.  The NAEC submitted a FOIA request for documents related to approval of the permit modification so that we can better understand how a doubling of the number of wells is a minor modification under the UIC well regulations.

Reclamation Bond

In 2007, Alaska Gold Company posted a $6,844,700 bond for reclamation and long-term monitoring of both the Rock Creek and Big Hurrah sites. This bond can be used entirely for reclamation of the Rock Creek site.

click here to download a factsheet on the Rock Creek Mine. 

last modified Mar 26, 2010 05:14 PM