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EQUIPMENT OPERATORS CRITICAL TO EFFECTIVE BLASTING OPERATIONS
Editorial focus by Harold Hough April/May 2009

An effective blasting operation can drastically reduce costs in either a mining or quarrying operation. However, those savings can only be realized if the operation has competent drilling equipment operators.
The blasting process begins with the rotary drill, which is a major capital investment that requires constant maintenance. A diesel rotary drill will consume 10% to 12% of its initial cost in parts and labor in the first 2,000 hours of operation. Each succeeding 2,000 hours may see these costs rise to 15%. If you don’t focus on scheduled maintenance, those costs can go up.

A mine also needs drilling equipment backup. According to heavy equipment experts, a diesel drill requires rebuilding every 2,000 hours of operation. If a mine works two eight hours shifts a day, five days a week, then the drill will require rebuilding every six months. Since the drill will be out of service for one to two weeks, a mine either needs to slow the operation or have a second machine available to pick up the slack.

A mine can reduce that maintenance cost and improve the productivity of the drilling and blasting operation by focusing on the person in the rotary drill cab. Since many rotary drill failures are operator originated, a skilled operator, can keep maintenance costs down, even if the training is expensive and his salary is high. A skilled operator knows the equipment’s capabilities and won’t abuse it. The fast, jerky motion of a rookie not only leads to poor drilling, it damages equipment. Jerking motions produce large impact forces within the equipment structure and hydraulics. These inevitably cause stress fractures and failures, leading to a dramatically lower equipment life.

Skilled drill operators know that steady drilling and loading will make the machine’s operation smoother while a small mistake can put too much torque on rotary parts. While it still takes the same amount of force to drill the hole, smooth operations spread that force out over a longer period of time. This will lower impact forces, reduce stress, and improve productivity over the long run.

Most mine operators don’t know it, but well trained operators can help prevent expensive maintenance. Skilled operators can recognize problems before they occur and inform the maintenance people before something expensive breaks. This avoids delays and keeps production costs down.

Meanwhile, marginal operators cost a lot of money. If a blast hole drill is only operated by a fair operator (90 percent as good as an experienced one), than the mine is not only operating at 90% efficiency, it is having an impact on maintenance because he is only getting 1,800 hours of work out of the drill between overhauls. That’s one to two percent of the initial cost of the equipment for every 2,000 hours of operation. Therefore, if the drill costs $75,000, and runs 4,000 hours a year, the addition cost of fair drill operators will be $3,000 a year in additional maintenance alone. This doesn’t include the economic costs of not running your mine and equipment at full capacity or the risk of equipment damage due to abuse.
Compare that to a highly skilled professional operator who can get an extra 10% more out of the equipment than the skilled operator. He is helping produce 10% more ore per rebuild cycle, which equates to 25 extra shifts of work per every 2,000 hours of operation.

Even with a good operator, your rotary drill will require maintenance. The drill has to operate in a hostile environment of its own creation by cutting, grinding, and pulverizing rock and then spewing it up to the surface. Above ground, the drill’s derrick must rotate the drill and feed the pipe so the structure is subject to heavy loads and twisting. As a result, even with good maintenance, a drill will require maintenance two to three percent of the time.

How your mine conducts maintenance will have an impact on the availability of the drill. If a mine operates on a continuous basis, more equipment should be purchased so individual pieces can be pulled out for scheduled maintenance. If the mine has maintenance days like Friday or Saturday where mining stops, the extra drills aren’t necessary. If the mine doesn’t have a good maintenance program, less money should be spent on equipment with the remainder going to instituting a good maintenance program.
Vendor support is also critical to keeping equipment running. Some drills made in other countries are cheaper, but spare parts must be ordered from the factory and the delay may cost several weeks in down time. A supply warehouse in the United States can limit the problem.

Although operator experience appears to be minor issue, it has a considerable impact on your drilling and blasting operation. If a mine stresses these things up front, the operations costs for drilling equipment can be dramatically lowered and unprogrammed down times can be nearly eliminated.