Narrow Vein Mining: Dynatec Experiences in Contract Operations

Symposium on Vein Deposits
Abstract Dynatec Corporation is an integrated mining services company, providing mine development, operations management, engineering, drilling and metallurgical services to the mining industry. At Franco-Nevada's Ken Snyder Mine in Midas, Nevada, Dynatec is the contract operator for the 850 tons per day underground gold mine and milling operation. The Ken Snyder Mine was brought into production in January 1999. In the 2001 fiscal year, 251,000 ounces of Gold was produced.

Access to the underground mine is via the main ramp from surface. For ore access, spiral ramps are driven from the main ramp at 1,000-foot intervals along the strike of the vein. From the spiral, the ore is accessed at 50-foot intervals, and sill drill drifts are driven along the strike of the ore. The ore occurs in a narrow (3 to 8 feet), steeply dipping (+750) quartz/carbonate veins. Mining widths average 5.4 feet. Stoping is carried out using longhole methods with Boart Stopemate BCI-2s drilling 40 foot long 2 ½" blastholes between sill levels. All mucking is done on the plane of the ore using remote controlled 1.25 to 3.0 YD3 LHDs. Stopes average 50 feet along strike, with development waste used for backfill. Mine dilution, grade control and minimization of metal loss are critical to the success of the operation.

This paper provides an outline of mining practices, lessons learned and successes in narrow vein gold mining at the Ken Snyder Mine. The discussion explains the context of a Contractor Management arrangement at Ken Snyder. The main focus of this presentation is to provide a description and review of operating procedures, including development, longhole drilling, blasting, mucking and backfilling practices at the mine. A review of best practices in industry and recommending a strategy for improvements is also presented.

Keywords: longhole, Mucking, Backfilling, operating procedure, Drilling, contractor management, Blasting, Best practices
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