Letters THE LOWDOWN ON THE ALPINE LOADER

I was interested to read the article in the June issue of your magazine entitled “High-Speed Mucking” and especially the portion on the Voest Alpine AL-60 loader.

Unfortunately, the writer does not appear to have contacted the end user, Brunswick Mining & Smelting, or the supplier, Wajax Industries, and consequently there are some inaccuracies in the article. An AL-60, in the development loader configuration, was used two years ago to drive an access decline at Woodlawn mine in New South Wales, Australia. That unit was equipped with a “swivel-mounted belt conveyor” in order to parallel load trucks in tunnel development.

The unit supplied to Brunswick Mining & Smelting this year is a drawpoint loader. It has a single, low- maintenance apron conveyor, not a “swivel-mounted belt conveyor.” It is indeed the first AL-60 in Canada and the first in the world in a production drawpoint application. However, there are now four units in Australia, two being delivered to underground min ing operations this year.

A most significant feature of the Voest Alpine loader is its front-end configuration, which is very similar to that of a hydraulic shovel and quite different from “the more traditional loader bucket” mentioned in the article. The bucket does not crowd the muckpile using traction from the machine’s crawlers but, rather, hydraulics push the bucket into the muckpile with the machine in a stationary position. Like a hydraulic shovel, the machine can attack the muckpile at any elevation from the floor up. This reduces track wear, allows the operator to work into a compacted drawpoint, allows him to selectively put aside oversize material, and also permits him to scale the drawpoint brow. Then there is the safety feature of having the bucket well ahead of the machine when the boom is extended, thereby protecting loader and operator from runs of muck.

I’m afraid your writer missed the main advantages of the machine. Low fuel consumption, when comparing the diesel powered AL-60 with a front end loader on tunnel development, is a feature. However, the machine at Brunswick is an electrically powered unit, and in a drawpoint application there are more important factors — high productivity, low maintenance costs, reliability, ample digging power, the ability to penetrate compacted muck, and the ability to control the flow of muck in the drawpoint with the bucket.

I suggest that the operating people at Brunswick Mining & Smelting can give a more complete picture of the success of the AL-60 in their mine. Rick Godfrey, Vice-President, Wajax Industries