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African narrow vein copper mine generated US$286,000

copper africa narrow vein

Commodity Ore Grade Geology Powder Factor Flitches Location
Copper High** Narrow Vein 0.7 kg/m3 2 Africa

This African copper mine operates three active open pits. The predominant mineralisation is structural in nature and is found in a narrow-vein which dips differently in each pit.

  • Ore polygons are delineated using assay data taken from reverse-circulation drilling performed prior to blast hole drilling
  • Blasts are relatively narrow (max width ~25 m (80 ft)), highly confined on both sides and in the front face
  • The site mines two flitches of 3 m (9 ft) each on a 6 m (18 ft) bench

Challenges

Lack of accurate blast movement data from BVI solution
  • The site had tried to use BVIs (poly-pipes) to measure blast movement
  • Recovery of the pipes was poor; mine personnel successfully recovered only one BVI per month
  • Polypipe data did not accurately measure the bulk movement of the blast because the surface moved much less than mid-bench

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 and dilution that would have occurred without monitoring
  • Ore polygons were translated based on the measured movement, and the new polygons were provided to the shovels

Results

Less dilution and more ore—added US$286,000 in one blast

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

  • Mid-bench horizontal displacement was 1.0 m to 11 m (3 to 36 ft). Vertical movement was measured as up to 6.0 m (19 ft), 1.6 m (5 ft) at the flitch boundaries

By accounting for blast movement accurately, this mine:

  • Avoided sending ore to the waste dump—3,400* tonnes (27%) in the top flitch and over 1,800 tonnes (14%) in the bottom flitch
  • Reduced dilution of 421 tonnes
  • Generated US$286,000*** additional value in this blast

* Numbers are rounded
** Average grade of ore polygons
*** Calculated at a copper price of US$5,500/t

Blast movement and polygon translation recovers an additional 3,400 t of ore in the top flitch

copper africa top flitch