An Ohio Producer Utilizes Electronic Detonators to Improve Its Blasting Program

Often, when an operation switches to electronic detonators for its blasting needs, it's because of a problem, such as excessive vibration. However, at the C.F. Poeppelman quarry in Bradford, Ohio, that wasn't the only factor.

The quarry produces crushed limestone, sand, agricultural lime, ready mix concrete and building supplies. While the company is sensitive to its one nearby neighbor and the surrounding community on the property's outskirts, the decision to switch to electronic detonators was made because, simply, owner Jim Poeppelman is interested in new technology. This led the company to recently start using the Daveytronic Digital Blasting System with electronic detonators from Davey Bickford USA Inc.

"The product interested me because we use the information obtained from signature holes and the programmable features of the system to get rid of vibration concerns," says Poeppelman. "But, the real reason we tried this product is because we like trying new things."

Poeppelman's Daveytronic suppliers, Jamie Kridler and Mike Miller of Ohio-based Northern Ohio Explosives, brought the product to the quarry, and the benefits were seen right away.

"Jamie told me up front that these explosives would cost two cents per ton more on the pattern," says Poeppelman. "But, he felt we could expand the pattern and lower the cost. What I liked was the accuracy. With other products we used, we were talking plus or minus six percent on the timing, so we could've had two adjacent holes detonating at the same time or even out of order, which is unacceptable."

The timing inaccuracies experienced by Poeppelman are typical with many mining operations. Inherent cap-scatter to either side of the delay found in pyrotechnic detonators can be six percent or higher, which affects the timing and amount of powder used for a blast.

"Today's empirical formulas for blast design were developed with pyrotechnic technologies and the inaccuracies inherent to them," says Robert McClure, manager, blasting initiation systems for Davey Bickford. "Typically, the result is in an overcompensation of the powder factor and longer period delays and blast duration."

Common problems with any blasting operation include poor rock fragmentation, high ground and air vibration levels, fly-rock incidents, increased need for secondary blasting and increased excavation and crushing costs. The Daveytronic Digital Blasting System helps alleviate those problems by offering programmable, repeatable blasting accuracies to within 0.10 ms.

Adjust on the fly

"The Davey Bickford product is nice because of the safety aspect, in that you can check every cap," says Poeppelman. "Plus, if, down the road, we get into vibration problems, you can adjust for them."

According to the company, vibration prediction and control models utilizing the Daveytronic have reduced vibration levels by as much as 48 percent and successfully mitigated the low-frequency impacts of production blasts. Also, fragmentation studies conducted in several North American aggregate operations have documented a 20 to 35 percent increase in rock fragmentation and more uniform muckpiles.

Excavation time studies and crusher throughput analysis studies also concluded that high accuracy detonators improve productivity while lowering excavation and crushing costs as much as 10 to 15 percent. The implementation of the Daveytronic detonators in large-scale overburden casting operations has documented blast-casting efficiencies up to 45 percent.

The first shot Poeppelman tried with the Daveytronic explosives was done on the same pattern as previous blasts: 10-ft. x 12-ft. wide, 4 1/2-in. in diameter, 73-ft. deep. It was a success.

"It just hammered the shot," says Poeppelman. "We had to lower the column on top."

On the second shot, they expanded the width 2 ft. to 10 x 14 - a move that not only made a blast that came in at 2.1 cents cheaper, but one with great fragmentation and with a 14 percent powder factor reduction.

"There's a little cap rock on top, but I don't care about that - we've got a breaker," says Poeppelman. "We'll get eight to ten pieces of oversize in each shot, but the middle of the shot is phenomenal. We may move out one more foot to 10 x 15."

The 10 x 14 pattern resulted in a 5 percent drill and blast cost reduction. Kridler expects the 10 x 15 pattern to result in an 11 percent drill and blast cost reduction.

Two at a time

The quarry blasts two faces at a time, with three different shots. Each shot has 40 holes in 2 rows. Jim Poeppelman does the layouts of the holes and Northern Ohio Explosives does the blasting. The relationship has been very good to the quarry.

"We can preplan the blast and pretest it, and you can't do that with other products," says Poeppelman. "Plus, it's cheaper."

After the blast at the Poeppelman quarry, the product is loaded onto a Komatsu WA600, two 50-ton Euclids and a 35-ton Cat 769, and then hauled to the primary crusher, a 4340 Cedarapids.

Secondary crushing is done by a Stedman cone crusher (for 3-in. plus) and a Nordberg cone crusher (for 3-in. minus). Screening is taken care of with two Tyler and one Deister screen. The quarry features a dry and wet side plant with a dewatering side that makes agricultural lime.

"We've got 20 different products, different blends, even a topsoil shredding machine," says Poeppelman. 'We sell everything but the squeak."