This gold mine is one of the top producing open-pit gold operations in West Africa.

• The ore deposits are structurally controlled conglomerate reefs, which are separated by quartzite waste rocks
• Operations are carried out over two pits, currently mined in two and three 3-metre flitches
• The site contains low and high ore grades

Challenges

Visual controls did not prevent post-blast ore type misclassification

• Deposits were visually controlled
• Significant misclassification was occurring, with high grade ore blocks moving into low grade ore blocks after blasting, and vice versa

Results

Less misclassification of high and low ore grades
Recovered US$250,000 in one blast

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

• Horizontal movement, recorded by BMMs, ranged from 3.5 – 6.4 m and vertical movement was up to 3.0 m

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

• Prevented ore type misclassification—3,480¹ tonnes would have been sent to the wrong destination
• Maximized ore yield—recovered an additional 200 oz (5,400 tonnes of ore), valued at US$250,000²
• Reduced dilution—3,800 tonnes of waste was diverted from the mill, saving $US68,400³ in unnecessary milling costs

* Average grade of ore polygons
1. Numbers are rounded
2. Calculated at a commodity price of US$1,250/oz.
3. Calculated on mill processing cost of US$18 per tonne