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Anaconda Mining increased ore recovery and reduced dilution to 5%
Anaconda Case study Gold

Commodity Ore Grade Geology Powder Factor Location
Gold 1.3 g/t* Narrow Vein 0.9 kg/m3 Canada

Anaconda Mining, a Canadian Junior, operates the Pine Cove Gold Mine and Mill located just outside of Baie Verte, Newfoundland.

  • Gold mineralization is hosted within quartz veins, dipping gently to the north with an east-west strike
  • Blasting occurs on 6 m (20 ft) benches and excavators selectively mine small ore pockets in a single pass
  • Grade control uses blast hole assays

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Challenges

Small polygons were not recoverable
Dilution was affecting mill feed grade
  • Ore production was falling because small ore polygons were not recoverable. The polygons, as small as two blast holes wide, were being entirely displaced from their in situ location by blast movement
  • Dilution, up to 20%1, was affecting grades and ore recovery

Solution

The BMM System accurately 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, dilution and misclassification that would have occurred without monitoring

Results

Dilution reduced to less than 5%
15% increase in overall recovered tonnes

Implemented in FY15, blast movement monitoring enabled Pine Cove mine to:

  • Recover smaller zones of ore, which contributed to an overall increase in ore production: 15% in FY16 and 9% in FY171

As a result of accurately accounting for blast movement, the mine reduced dilution from 20% to less than 5%2:

  • Dilution remained below 5% through FY16 – 17

In an example blast from Pine Cove mine:

  • Measured horizontal movement ranged from 2.6 to 8.2 m (8 to 27 ft) and vertical movement was up to 2.2 m (7 ft)

By translating post-blast polygons in one blast, the mine:

  • Avoided 23% dilution, or 2,884 tonnes of waste being sent to the mill
  • Recovered an additional 2,912 tonnes of ore, valued at US$80,8773

* Average grade of ore polygons
1. anacondamining.com (FY 15, 16 and 17 financial results)
2. Company supplied data
3. Calculated at a gold price of US$1,200/oz.
Image©davehowellsphoto.com

At Pine Cove, blast movement entirely displaced the small ore blocks. By accounting for movement in this example blast, the mine avoided 23% dilution and recovered an additional 2,912 t of ore.

anaconda gold case study

“The decrease in overall dilution, from 20% to less than 5%, has made a huge impact to our project, not just in improved economics but also in reduced tailings production and overall project footprint. Using the BMM System we can mine small zones of ore—increasing overall recovered tonnes. Without BMT we would not attempt to recover these small polygons due to movement.”

Gordana Slepcev, COO, Anaconda Mining

 

Jordon Cramm, Mine & Engineering Superintendent, explains how the BMT solution has improved the blasting practices, and reduced dilution and ore loss at Pine Cove. The system has increased recovered value by US$15 – 30k per blast.

Garry Luffman, senior geologist at Anaconda Mining’s Pine Cove mine, describes how the geology team use BMT’s blast movement monitor system to recover narrow ore zones.

The thin areas experienced high dilution, over 20%, which resulted in lower feed grades through the mill. Using the BMM System, Pine Cove has reduced dilution to 5%, increased the grade and limited the waste going to the mill: realising US$15,000 to $30,000 dollars per blast.