Having a blast - efficiently
January 1, 2007 By: Rodney E. Garrett Pit & QuarryA North Carolina producer optimizes its drilling and blasting programs with frequent monitoring and adjustment of equipment.
Once the overburden is removed, the quarrying procedure starts by drilling and blasting in-situ rock. For the quarry manager, the quest is to carry out both activities for the least cost possible, just as he aims to do with the crushing/screening process.
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In order to optimize the drilling and blasting programs, the manager will revisit them periodically to see whether a change can improve the financial bottom-line picture. Depending on the program, it might be the simple matter of just shaving costs by making small adjustments to the program – or it might mean taking a major step by replacing equipment or changing the method for carrying out the production procedure.
Some of the more common questions that come to the fore when evaluating a given operations program include:
- Is the equipment still acceptably reliable?
- Does it have the optimum capacity for the present operation, or has it become a bottleneck?
- Is there a better and more efficient way to accomplish the task?
Case in point
Ararat Rock Products Co., a family-owned quarry in Mt. Airy, N.C., believes in periodically addressing these types of questions, and manages the company accordingly. This philosophy has enabled the Crossingham family for the last three generations to have a successful business that is now 50 years old.
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Ararat Rock Products Co. was founded in 1955 by "Big" Jim Crossingham after he returned from the Korean War as a U.S. Navy Seabee. It was during his stint with the Seabees that he became interested in construction – and more pointedly, the quarrying and crushing/screening of rock for construction purposes.
While Big Jim is still involved with the quarry operation, he also manages the family's textile business that was passed down from his father, Jim Sr. "Little" Jim, Big Jim's son, is currently president of Ararat Rock Products and Little Jim's son, James IV, is the vice president.
 The move to trade up to the bigger-capacity drill rig has proved to be cost-effective and more production-efficient for Ararat Rock Products, Mt. Airy, N.C. |
There are different views on what blasthole drilling program is best. That is because the "best" program will be different for each quarry operation. To illustrate, some quarry managers find it is more cost-effective to contract with a drilling contractor for drilling the blastholes, while others find it is more efficient and cost-effective to own a drill rig and carry out all blasthole drilling in-house.
Ararat Rock Products has been doing its own blasthole drilling for many years, and recently traded in an Ingersoll Rand DM25 drill rig it has owned and operated for the past 19 years. While that rig had been effective and productive for its size, the Crossinghams decided it was time to purchase a bigger capacity rig.
The newly purchased drill rig is an Atlas Copco model, DM30. Atlas Copco recently bought the Drilling Solutions Division from Ingersoll Rand because of its fit with existing complimentary products in the company's line. The traded DM25 drill rig was recently bought by another company, so it, too, is still in service.
 At Ararat Rock Products, different bench/face layouts vary considerably throughout the quarry, so a round of a blasthole's overall width can range from 100 to 200 ft. |
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