Blast Movement Monitoring

Blast movement is highly variable

Controlling ore loss and dilution is critical for all mining operations. Getting it wrong can result in tens of millions of dollars of lost revenue per year.

You want the ore, that you’ve spent money defining and grade-controlling, to end up in the mill. But ore movement occurs in all blasts. And failing to account for movement post-blast means that ore is sent to the waste pile, and waste to the mill.

Blast movement varies with depth, across the different zones of a blast, and is compounded by edge effects—making it impossible to predict/model blast movement with sufficient accuracy for ore control purposes.

BMT’s solution collects data from blast movement monitors, which move with the blasted material. The software calculates the post-blast 3D movement location of the ore polygons and outputs new dig lines.

Accurate blast information enables grade control to recover all of the planned resource and achieve the true life of the pit.

BMT, a Hexagon Company

What is blast movement?

So that solid rock can be excavated, explosives rapidly release energy to fragment the mineral resource. The explosive exerts a force equally in all directions, and the rocks with least resistance begin to move. Typically, movement is perpendicular to the blast initiation timing contours. The moving rocks in turn act on neighbouring rocks, which results in bulk movement of the rock mass.

• Upon detonation, each discrete element of the explosive exerts a force equally in all directions on the adjacent rock. The rocks with least resistance, that is rocks with less un-blasted rock in front of them, begin to move. These rocks in turn act on neighbouring rocks, which results in bulk movement of the rock mass.
• The rock moves in the direction of least resistance. The material moves into the void created by the hole before it and the new material settles into the new location, making movement approximately perpendicular to the initiation timing contours.
• The rock at the top of the bench is not directly impacted by the explosive but instead is indirectly moved by collisions from other rocks from the drill hole behind. The further a rock is above the explosive column, the less energy it receives and therefore the less distance it will move.
• Greater movement is in the mid-to-lower level of the bench and movement reduces near the floor due to friction from the unbroken floor.

The blast monitoring process

The benefits

Get more from your resource

The Blast Movement Monitoring System (BMM System) is the most accurate and profitable 3D blast movement monitoring method available.

Reducing ore loss is pure profit

You still mine the same amount of rock, send the same number of trucks to the plant, process the same amount of ore. The only difference is that with the BMM System, there is more mineral produced by the plant.

More revenue for an incremental cost

By adding only a few cents per tonne to the cost of ore blasts, you can significantly reduce ore loss and dilution, improve reconciliations and potentially gain millions of dollars’ worth of extra mineral. Without BMM sensors, that value would be lost to the waste dump, never to be converted into revenue.

Teck Resources Limited: Highland Valley Copper

Teck’s Highland Valley Copper (HVC) Operations, an open-pit mine located in British Columbia, Canada, produces copper and molybdenum.

The magnitude of blast movement at HVC was expected to be low and, given the gradational nature of the ore body, the movement was not considered to be a contributing factor to dilution or ore loss.  However, poor reconciliation indicated ore loss and dilution were a problem at the mine. The grade control team realised they could improve ore recovery by moving ore polygons to post-blast locations. (Source: Teck Resources Limited)