The Swede’s lead

When Mike Amsden, Falconbridge’s vice-president and general manager for Kidd Creek Mines, travelled to Stockholm earlier this year to attend the 13th World Mini ng Congress, he took a $1.25-million purchase order with him. He took time off f rom the congress to visit Kiruna Electric, a Swedish company 25%-owned by Atlas Copco, to order an electric 50-ton truck that his staff had thoroughly checked o ver during the past year. The sale was a long time coming. Kiruna has had a prototype truck working at Boliden Minerals’ Kristenberg mine on a test basis since November, 1986, but it h ad never sold one. The Kidd Creek order is the first sale. It could prove to be a big breakthrough for both Kiruna — it now has another dozen potential sales i n the negotiation stage — and for Kidd Creek.

Kidd Creek’s huge zinc-copper- silver mining and smelting complex at Timmins, Ont., is already considered a state-of-the-art operation, but the company realiz es that it must constantly find ways of improving efficiency to maintain profita bility. Going electric appears to be one way Kidd Creek is doing that. But findi ng the right equipment is a problem. Heavy electric mining equipment is a new ph enomenon, but it seems to be the way of the future. It’s not surprising that after a long search for satisfactory equipment, Amsden ended up in Sweden. The c ountry’s long history of design and engineering excellence coupled with a mining industry that dates back at least 1,000 years, has allowed Sweden to de velop ne w mining technology — and test it under working conditions. In fact manufacturi ng mining equipment is quickly eclipsing mined products in importance as an expo rt.

Mining in Sweden isn’t what it used to be. While Sweden still is a net exporte r of minerals, mining is what is called a “mature” industry. Mineral output has been on the decline since the Second World War.

But when it comes to mining equipment manufacturing, Sweden is a world leader.

Since 1945, base metals mining companies in other developed countries relied o n unprecedented economic growth to force up commodity prices, allowing them to n eglect productivity improvements in favor of simply increasing output. In Sweden , however, things were different. The country’s high standard of living combined with a high degree of state- sponsored social benefits — which means a high de gree of taxation for industry — has forced Sweden’s mines over the past half ce ntury to increase productivity through greater mechanization. Now, with base met al mines in the developed world no longer able to rely on increasing commodity p rices to pay for labor-intensive methods, there is a great demand for Sweden’s t echnology.

So it’s not surprising that Sweden’s mining equipment manufacturers have becom e world leaders, with equipment manufacturers taking on a disproportionate impor tance compared to the country’s mining industry. Atlas Copco, for example, is on e of the world’s leaders in manufacturing mining equipment and other equipment, but it has to sell 90% of its products outside of Sweden.

There are many examples of Sweden’s innovation in mining equipment. We’ve pick ed three that caught our eye at the trade show that was held in conjunction with the World Mining Congress.

The Kiruna truck is more than a piece of equipment. It’s part of a new way of approaching underground mining operations. Amsden calls it “pay- as-you-go minin g.” Bjorn Lindstrom, production manager at Kiruna, calls it “cash-flow mining.” Whatever it’s called, the basic idea is the same: ramp haulage rather than hoisting.

Ramp haulage is nothing new, but electrical powered haulage of larger payloads makes it economical for bigger, deeper mines. Diesel power is too expensive and requires too much ventilation to be effective over any but the shortest haulage routes. And the electric trucks can move the material quickly. With a 50-ton payload it negotiates grades of up to 12% at 20 km per hour.

Ramp haulage allows shallow orebodies to be mined more quickly. The time requi red to gain access by way of a ramp is much less than the time required to sink a shaft and crosscut over to the orebody. The capital cost, therefore, is lower before ore is mined, producing cash flow for the operation.

In Kidd Creek’s case, the electric trucks will be used to ramp down to lower l evels of the orebody rather than deepen the No. 2 shaft. The company’s purchase includes 1,200 m of trolley line plus an option for another truck to be delivere d in 1989. The truck is powered through a trolley line, bolted to the back of th e ramp. At bypassings, turnings, loading points and dumping, the truck is powere d by a battery.

Kiruna says it is in the final stages of selling two more trucks, with the opt ion for two more, to Hope Brook Gold, the bp Selco subsidiary developing the Hop e Brook gold deposit in Newfoundland.

Kiruna’s electric truck will have to undergo some rigorous testing under work conditions before being fully endorsed in the industry, but in Canada, where a t rend to ramp haulage is well under way, it appears to be a logical step in impro ving productivity. And although Kiruna says it has prospective customers for eig ht more of the trucks, it seems that Canada is taking advantage of this innovation.

Less “high-tech,” but also an improvement over existing methods, is Skega’s du mp body for conventional off-road trucks, used in surface mining operations. Fir st introduced in 1979, this item is finding a niche for itself as a way of reduc ing maintenance requirements and downtime on trucks.

The basic design involves a steel skeleton for the dump body with rub ber ropes suspended from side to side. A single-piece of rubber mat replaces the ste el bottom used for the body in conventional trucks.

The Skega dump body dampens and cushions the impact of falling rock, reducing wear on the truck’s body, chassis, suspension and tires. Skega also says the rub ber dump bodies will outlast steel ones.

An indication of how well the Skega product works is the satisfaction of its u sers. The customer who took delivery of the first 170-ton dump truck with a Skega dump body now has six. The trucks are in operation slightly more than 5,000 ho urs per year at a cycle time of 1.65 loads per hour.

One of the dump bodies’ benefits is the need for less steel to withstand the i mpact at loading. Less steel means less deadweight which translates into lower c osts in haulage. The rubber truck body can also be changed much more quickly, ag ain reducing downtime. Furthermore, because of the “live” floor of the body, the re is virtually no freezing of material to the truck body. There is therefore no need to use exhaust gases to heat the muck and the resultant corrosion that suc h heating causes.

Skega offers a number of examples of its truck bodies now in use. One Canadian example, although unnamed by Skega, is a copper mine where a Skega dump body operated 6,527 hours over a year with a truck availability factor of 75%. The rest of the fleet, 15 units, operated 5,878 hours each with a truck availability factor of 67%. Used on a Lectra Haul M 100, the Skega dump body’s lower weight mean t a 9.2-tonne increase in payload.

The dump body is now in use on more than 50 trucks ranging in capacity from 35 to 170 tonnes.

Not all of Sweden’s technical innovations are big-ticket items. A small Swedish company, Ilmeg Systems, has developed a piece of equipment that is fast becomi ng a fixture for underground drilling: an angle indicator that improves accuracy in collaring and drilling.

Correctly positioning the drill is important to drilling efficiency (as much a s 10% of the advance is lost when the angle and spacing of the drill are incorrect). Ilmeg says using its angle indicator can result in reduced overbreak, there by reducing scaling reductions in shotcreting. Set-up time is faster and trainin g time for new drill operators is reduced.

Ilmeg’s angle indicators are mounted on the drill rigs to measure both horizon tal and vertical angles. Drilling rigs can be fitted with
the angle indicator, b ut more often the drill rig manufacturer includes them. For example, Hope Brook Gold has had them installed on four Boart 2-boom jumbos which it has already tak en delivery of. The angle indicators are also in use at several other Canadian o perations including Dome Mines’ South Porcupine mine, Hudson Bay Mining & Smelti ng’s Trout Lake mechanized cut-and-fill copper- zinc-gold mine and the Page-Williams gold mine at Hemlo.