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Golden Queen’s Soledad Mountain Mine increases recovered value through blast movement monitoring

golden queen detecting muckpile

Commodity Ore Grade Geology Powder Factor Location
Gold 0.02 oz/Ton* (0.63 g/t) Narrow Vein 0.41 lb/yd3 (0.24 kg/m3) North America

Soledad Mountain Mine is a gold-silver mine located near the town of Mojave in southern California.

  • The mine uses conventional open pit mining methods, and cyanide heap leach and Merrill-Crowe processes to recover gold and silver from crushed, agglomerated ore.
  • The primary ore types are porphyritic rhyolite, flow-banded rhyolite, pyroclastics and porphyritic quartz latite.
  • The East Pit mines 20-foot (6 m) benches in one pass.

Challenges

Narrow host-vein geometries presented challenges to mine operations due to a high risk of ore loss and dilution
  • The extent of blast movement and its influence on ore zones was estimated
  • Designed ore-waste boundaries could not accurately account for blast movement
  • A buffer zone of material surrounding ore zones, incorporated to account for movement, was sent to the crusher

Solution

BMM System accurately measured 3D blast movement and translated post-blast dig lines
  • Blast movement monitors (BMMs) were installed in monitoring holes throughout the shot
  • Installation and detection as per site standard operating procedures
  • BMM Explorer software calculated new dig lines, and areas of ore loss, misclassification and dilution that would have occurred without monitoring

Results

Improved mining efficiency and stakeholder value
Average per-blast savings estimated at US$55,000

Within the first year of mining, Golden Queen Mining Company implemented blast movement monitoring. Soledad Mountain Mine’s results indicate a significant improvement in recovered Tons, estimated at US$55,0001 average value per blast, through:

  • Avoiding waste processing, and
  • Mitigating the effects of ore movement in a narrow, vein-hosted gold/silver deposit

An example blast (shown right) demonstrates measured ore movement and potential savings at the East Pit.

Significant movement occurs within all blasts. Variation of ±50% from the mean horizontal movement is common and occurred in this blast.

  • Measured horizontal movement2 ranged from 4.5 –10.5 ft (1.4 – 3.2 m) and vertical movement of up to 5.3 ft (1.6 m)

As a result of accurately accounting for blast movement within one blast in East Pit, Soledad Mountain Mine:

  • Improved recovered value by an estimated US$69,1952,3
  • Increased ore yield by 4,047 Tons (3,671 tonnes) and avoided 3% ore loss

* Average grade of ore polygons;
1. Golden Queen supplied data;
2. BMM System-measured blast movement;
3. Calculated at a gold price of US$1,350/oz.

“The BMT system provides an additional level of security for the project’s ore control operations. Through tracking the movement of ore zones, we ultimately bring more value to the project”

Sara Holden, Sr. Technical Geologist, Golden Queen Mining Company, LLC

Soledad Mountain Mine blast movement vectors

In this blast, Soledad Mountain Mine recovered an additional 4,047 Tons (3,671 tonnes) and avoided 3% ore loss.