Editorial Focus by Harold Hough

Are dropping minerals and metals prices forcing you to look at buying newer, more efficient processing equipment? Before you do, take a minute and read this article. You might be able to improve your processing without buying a single bit of new equipment. Just ask yourself if you need new processing equipment or a more efficient way to get material to your processing plant.

You may think that processing begins when the hauler dumps its load of ore at the processing plant, but that isn’t true. Efficient processing depends on a steady flow of material that keeps the equipment running at its optimum capacity. If your equipment is left underutilized because the trucks aren’t moving from the mine face to the processing facility in a timely fashion or its being pushed too hard because large piles of ore are sitting around, you are wasting money and manpower.

Contrary to what you may think, new processing equipment isn’t the best way to improve productivity. According to Caterpillar; machinery availability, maintenance, and the money spent on equipment ran, 5th, 6th, and 7th in ways to improve productivity in terms of lowering cost per ton. The best way to improve your mine efficiency is by improving the cycle time from the mine face to your processing plant. Here are some suggestions from Cat.

IMPROVE YOUR HAUL ROADS. Your mined material probably spends more time on your haul roads than anywhere else. And, if the roads are poor, the time spent there is even longer.

It’s not just time that is spent on haul roads. Poor roads increase fuel consumption, equipment maintenance, tire costs, and driver fatigue. Good roads cut the time spent in mining and processing your ore. Good roads also get your product out the door to customers faster.

According to Cat, if you can comfortably drive your haul road at 60 kph in a light truck, it is in good condition. That allows your haul trucks to travel safely at the fastest and most fuel efficient speeds.

The key to productive haul roads is to fix the road as soon as you see a problem. Once a road deteriorates, it takes five times as long to repair it to good condition again. The motto should be, “Fix it once, fix it right.”

DUMPS ARE PART OF THE HAUL ROAD SYSTEM. Some mines think the haul road system stops when the truck turns off into the dump area. This is not true. In fact, considering the time spent at the dump site and the need to maneuver at the site, it can take a large percentage of your total haul cycle time.

Dumps are the most likely area to need repair. Not only is lose material more likely to be found on the driving surface, the mechanical strains on the surface as trucks start, stop, and maneuver can tear the surface up quicker. The result is a high rolling resistance that uses more fuel, and a lower speed that forces your hauler fleet to spend more time there.

Mines need to be aware of the problem and keep manned dozers and graders on site that can move spills and regrade immediately. As with the rest of the haul road system, immediate attention takes less time than repair.

LOOK AT FIRST AND LAST HOUR PRACTICES. Studies show that the first and last hour of a shift are the least productive. Part of that is due to changing the shifts, but much is because of inefficiencies. For instance, many mines want the hauler operators to drop off their last load of ore and then proceed to a parking place to change crews. What happens is that many trucks, caught in mid haul cycle, will dump their last load and then proceed slowly back to the parking area because they don’t have enough time to take another load. This impacts your processing plant, which doesn’t have enough material to process at the end or beginning of the shift.

One way to avoid the lost productivity during the first and last hour is to have your trucks stop at several parking areas along the haul loop and then picked up the drivers with a van. When the next shift starts, they start the haul cycle where it stopped. Trucks that were full continue to the processing plant and empty trucks continue back to the mine face. The result is that the processing plant continues operating at a steady rate instead of waiting for new material as the haul cycle starts up with each new shift.

Although we often think of processing in terms of equipment and machinery capacity, processing is just as much about getting the material to the plant on time and in the quantities needed. If you look at it that way, you can improve your processing operation quickly with a small investment.