Explosives supplier BME is setting up a 318 m vertical pipeline – the longest in the world – to enable the direct delivery of emulsion to a South African underground mine, BME senior operations manager Selwyn Pearton says.

This pipeline is expected to be commissioned by the end of next month.

“If they are willing to invest in the capital, mines now have the option to streamline their emulsion delivery systems for underground operations using a vertical pipeline instead of the mine shaft,” Pearton states.

To deliver emulsion to underground mines, transfer cassettes are typically loaded with emulsion above ground, which are then collected by carriers that are driven down into the mine or lowered through the shaft. However, the deeper the mine, the more difficult it is to deliver emulsion in this manner, Pearton explains.

He notes that up to 10 t/d of emulsion is used for blasting, which amounts to a significant operational burden.

Pearton says shaft time can be a significant constraint on a mine’s operations, but using a vertical pipe that delivers emulsion from above ground, down through a borehole to an underground storage tank, can eliminate this.

This more direct approach requires only one mine operator and enables mining companies to increase production rates at mine shafts, which was previously not possible, owing to increased available shaft capacity, he emphasises.

Pearton advances that this method also simplifies the delivery of emulsion to underground rock faces, particularly when compared with the complex logistics systems associated with Class 1 presensitised explosives, such as ammonium nitrate fuel oil, commonly known as Anfo.

“The logistics factor is one of the primary advantages that emulsions have over cheaper, presensitised explosives, and this process makes the claim stronger.”

He explains to Mining Weekly that the risk during transportation, and the resulting administrative burden imposed by law to account for and closely monitor all the quantities of presensitised explosives, make the use of Class 1 explosives much more cumbersome than using United Nations Class 5.1 emulsions, which become an explosive only when mixed with a sensitiser at the rock face.

The use of presensitised explosives in ATM bombings has resulted in strict enforcement of mine regulations and Section 54 stoppages, costing mines millions of rands in downtime each day.

The use of pumpable emulsions limits regulations and the risk of Section 54 stoppages associated with Class 1 explosives. This results in increased safety, not only for mine personnel, but also for the mining company as a whole.

Portable Charging Unit
BME marketing manager Hayley Wayland says global mining major Anglo American Platinum is currently trialling 54 of BME’s Portable Charging Units on a single shaft complex to test the overall benefits to the operation.

The unit consists of a pump, a tank of sensitiser and BME’s Closed Emulsion System, composed of multiple refillable emulsion bags for the transport of emulsion to the face. The bags are refilled underground and attached to the pump, which is light enough to be carried by hand.

The purpose of the pump is to combine a small percentage of sensitiser with the emulsion to create an explosive that will be delivered into the blast-holes at the rock face.

Pearton says it took seven years to develop the unit, which is made as light as possible so that it can be easily transported into small areas such as narrow-reef operations.

Previously, charging equipment was extremely bulky, weighing up to several tons, which made it extremely difficult to manoeuvre, especially in tracked, confined environments, he explains.

In addition, the supply of emulsion to the pump through the closed emulsion system eliminates any emulsion being wasted or contaminated, which other explosives-delivery processes are prone to, Pearton says.