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Nickel mine generates $640,000 additional value in one blast

Commodity Ore Grade Geology Powder Factor Location
Nickel 0.6%* Disseminated 0.7 kg/m3  Australia

This mine is one of the world’s largest, low-grade Nickel open-pit operations.

  • The mine resource is a sulphide deposit in ultramafic rocks
  • Blasts are fired in 12-metre benches and mined in a single pass
  • Grade control uses RC drill assays

Challenges

Talc contamination reduced Ni recovery;
Lower than expected mill grades
  • Talc ore, not accurately classified and stockpiled, was contaminating non-talc ore in the mill, which reduced Ni recovery
  • Dilution impacted mill feed grades
  • Mining ore in narrow zones increased dilution

Solution

The BMM System accurately measured 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 mill grade and Ni recovery;
Added $640,000 of value in one blast

As a result of accurately accounting for blast movement, this mine:

  • Correctly classified and treated talc-contaminated ore, improving Ni recovery
  • Improved Ni grade from the mill when mining ore in narrow zones by reducing dilution

Significant movement occurs within all blasts. Variation of ±50% from the mean horizontal movement is common. In an example blast:

  • Measured horizontal movement ranged from 2 to 6 m (6 to 20 ft) and vertical movement (heave) of up to 3.5 m (12 ft)

By accounting for movement in this blast, the mine also:

  • Avoided misclassification of 24,5001 tonnes of ore (4%)
  • Recovered 12,500 tonnes of ore (2%), containing Ni valued at $640,0002
  • Avoided dilution of 18,000 tonnes (3%)

* Average grade of ore polygons
1. Numbers are rounded
2. Calculated at a commodity price of A$14,000 per tonne

In one blast, this nickel operation increased ore recovery by 2%, reduced dilution and avoided misclassification of talc and sulphide ores.