Asanko Gold’s Nkran mine, located in Ghana, is an open pit operation in the Kumasi Basin.

• Mineralisation is shear-hosted in a sedimentary basin with Granitic intrusions
• Blasts are fired in six-metre (20 ft) benches and mined in two flitches (3 m)
• A proven reserve of 4.4 Mt at 1.85 g/t gold, the site contains high grade ores (up to 2.0 g/t)

Challenges

Ore loss and dilution negatively impacted mill feed ore grade and ounces

• Ounces produced vs reserve model reconciliation was 18% below target
• Mill feed ore grade was 10% below reserve model expectation
• Blast movement, causing ore loss and dilution, was considered to be contributing factor

Results

100% reconciliation for ore grade and ounces produced

By accurately accounting for ore movement in production blasts, Nkran mine has achieved significant reserve model reconciliation improvements:

• Mill feed ore grade reconciliation variance of 102% (vs 88% over the previous period)¹
• Ounces produced variance of 100% (vs 96%)

Following is an example blast from Nkran that quantifies blast movement and additional value.

• Measured horizontal blast movement ranged from 1.5 to 11.6 m (5 to 38 ft) and vertical movement was up to 9.8 m (32 ft)

In this blast, the mine site added US$237,000 of value.

• Maximized ore yield—recovered 2,800² tonnes of additional ore at a value of US$137,000³
• Reduced dilution—diverted 5,500 tonnes of waste from the mill, avoiding US$100,000⁴ of milling costs

* Average grade of ore polygons
1. www.asanko.com
2. Numbers are rounded
3. Calculated at a gold price of US$1,250/oz
4. Based on milling costs of $18 per tonne