Modern Mining April 2016

EQUIPMENT

Stemming trucks from Scania can cut open-pit mining costs

A crucial part of the open-pit mining cycle is the blasting process and any equipment that can make this activity more efficient is highly prized by the mining industry. Stemming trucks are one class of product that can contribute to making blasting procedures faster and more efficient and Scania South Africa can now offer customers what it believes is one of the most efficient trucks of this type on the market. The stemming truck forms part of Scania’s extensive range of mining trucks.

S temming is a key element in the ‘drill and blast’ mining technique. In stemming, material such as fine gravel or aggregate is placed on top of explosives in drill holes. When the explosives are detonated, the stemming locks in the expanding gases and keeps the forces in the borehole until rock begins to break. The stemming truck’s duties are to fill blast holes on a mine site into which the liquid mix- ture of ammonium nitrate and fuel oil explosive charges has already been inserted. The holes are typically located at 5 m intervals in the area to be broken up. The stemming trucks available from Scania South Africa are the result of a partnership it has with Cobra Petro Projects. An initial truck

was manufactured and introduced to the South African market two years ago. One of South Africa’s most well established mining groups saw it and arranged a demonstration review. The truck impressed the company to the extent that it purchased the demo model. Within a few months two other units were purchased. The units are manufactured under licence to Ausroad, an Australian company which orig- inally developed them for a mining client in Western Australia. According to Becky Smith, Scania South Africa’s GM Mining, it is not uncommon in the South African mining industry to see the stem- ming function being performed by front-end loaders, which she says is not only inefficient but also tends to give inconsistent blasting

Becky Smith, Scania South Africa’s GMMining.

A completed Scania stemming truck ready for delivery.

results. In addition, backfill material either consists of aggre- gate that needs to be transported to the blast site or of the rock dis- placed through the drilling of the blast hole. This means that the material is not graded and spe- cific to the requirements of the blast – which affects efficiency. “This new stemming truck technology makes it easy to ensure that the correct amount of precisely sized aggregate is delivered into the blast holes in an efficient manner,” Smith says. Benefits of using the stem- ming truck include operational safety (one truck and operator) versus several smaller vehicles; being able to access hard-to- reach blast areas with an 8 m boom conveyor (170 degrees); and significantly decreasing the

44  MODERN MINING  April 2016