Quarry Blast Fragmentation Critical Factor for Pit Operations

Quarry blast fragmentation is a critical factor for pit operations as it has a direct impact on the management and cost implication.

PGSurvey Survey Operations

PGSurvey is a survey operation that provides a mine survey/mine planning service to small mines. The surveyor, who is in terms of the South African Mine Health and Safety Act, bound to provide a Geological Plan the Department of Minerals and Resources (DMR), is also in a good position to incorporate the geology into the mine planning and the layouts. As part of the management team of a mine, he is also in the position to quantify the planning.

In one of our client’s quarry, we have just recently set-off Blast 45 and we were involved in the pit planning as well as the blast layouts for the past 4 years. The surveyor is one of the best expertise to be involved in the drilling and blasting, provided that he understands some technical terms use in the blasting arena.

The surveyor should know what is fragmentation, burden, spacing, stemming, toe position, back-break and powder factor, all these items are not so sophisticated to understand, but is important to understand the influence of these factors on fragmentation.

Bad fragmentation is hardly a measurable cost item within the mining industry. The cost of breakage to the excavator’s buckets, the crusher liners and standing time, verse the extra costs spend on a well-planned drilling programme and extra explosive costs per blast where the rock is blasted into small fragments, is justified.

Fragmentation Optimization

A stagger pattern with a sub-drill were introduced in order to blast to an even floor and therefore every hole position was surveyed, a blast plan constructed, which depicts the drill depths of every hole. The plan was not only sent and to the Blasters but to the Mine Manager as well for review.

There are other factors which can influence the fragmentation, although we have reduced the drill pattern, the hole diameter and the allowable stemming the amount of explosives per hole is still limited.

As always, to find out more about PGSurvey services and operations, go to our Contact page to find out more.