Latin American silver mine created US$260,000 additional value

Latin American silver mine created US$260,000 additional value

Commodity Ore Grade Geology Powder Factor Location
Silver High Structured 0.9 kg/m3 Latin America
This operation is one of the top producing open-pit silver mines in the world.
  • Deposits are structurally-controlled in low to medium sulphide veins
  • Drills and blasts 7.5 m benches, mined in a single pass
  • Contains high grade (60 g/t) silver mineralisation with gold as a by-product

Challenges

Selective mining in a structurally-controlled deposit generated reconciliation issues when ore polygons move outside their original boundaries
  • Ore loss: unaccounted blast movement means material containing high grade silver ore is sent to the waste pile
  • Dilution: tonnes of waste are unintentionally sent to the mill
  • Misclassification of ore: high grade ore is stockpiled as low grade or low grade ore is sent to the mill as high grade

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

Results

Significant increase in ore recovery adds $260,000 of value—in one blast
Significant movement occurs within all blasts. Variation of ±50% from the mean horizontal movement is common and occurs at this mine.
  • Measured horizontal movement ranged from 7.3 to 10.5 m (24 to 36 ft) and vertical movement of up to 1.4 m (5 ft)
As a result of accurately accounting for blast movement, this mine:
  • Maximized ore yield—6,100* tonnes of ore were recovered, valued at US$200,000*** (avoided 30% ore loss)
  • Reduced dilution—6,000 tonnes of waste were diverted from the mill, resulting in 30% dilution and $60,000**** of unnecessary milling costs
  • Prevented misclassification—1,200 tonnes (6%) of ore would have been misclassified
* Numbers are rounded
** Average grade of ore polygons
*** Calculated at a silver price of US$19/oz.
**** Calculated from milling costs of US$10 per tonne
Accounting for blast movement improved ore recovery, adding US$260,000 of value—in one blast
Silver-Sth-America-structured-deposit  
Download Case Study
 Want to know more?