Keeping Up with the Demand
By Treena Hein
A high-quality granite quarry is the crowning glory of this third-generation aggregate and road
By Treena Hein
Danford Aggregates’ granite quarry near Madoc, Ont., was a very busy place in late November 2011.
Danford Aggregates’ granite quarry near Madoc, Ont., was a very busy place in late November 2011. The extremely mild fall weather had meant companies all over the province were able to stretch out their roadbuilding activities, and demand for Danford’s granite aggregates (FC1, FC2 Superpave) was still intense. “We fill orders from all over eastern Ontario and as far away as Hamilton in southern Ontario, which is about a five-hour drive from here,” says aggregate operations manager Jamie Danford. “It’s a very high-quality source of gneiss granite, which produces excellent asphalt with good skid resistance. The demand just keeps increasing.”
|Danford Aggregates’ granite quarry near Madoc, Ont., possesses a very high-quality source of gneiss granite that produces excellent asphalt with good skid resistance.|
Danford began operating the granite quarry five years ago. “We couldn’t keep up with demand even then, so three years ago, we went from two-stage crushing to three-stage to speed up production,” notes Danford. “In 2010, we realized we also had to stop moving the only crusher spread we had at the time from the granite quarry to our limestone quarries or gravel pits. We bought another spread that year and we move that one around, and the granite spread stays put.”
In addition to the granite quarry, the company operates two limestone quarries and eight gravel pits. Danford Aggregates is a separate business, added some time ago to Danford Construction, which was started by Jamie’s grandfather Samuel over 50 years ago. Still active in the business are Samuel’s son Walter (president) and third-generation family members and co-owners Jamie, Sam (equipment manager) and Al (operations manager). During their lifetimes, second-generation family members Brian and Doug also helped build the business.
In a year, the company handles 250,000 to 300,000 tonnes each of limestone, granite and gravel. There are about 50 employees during construction season, and about 40 during the winter when the company continues aggregate production as the weather permits, and also does some winter road maintenance subcontracting.
On the road construction side, Danford mainly handles excavating, with paving contracted out. “This year was unusual because we spent about three and a half months implementing the plan for the closure of a local historic talc mine,” says Danford. “It involved moving a lot of material to get the sloping done on areas that had been blasted, and it’s now an amazing rehabilitated site. The difference is incredible.” Danford is doing part of the work for another mine closure in 2012. The company has also had a CCIL-certified aggregates testing lab for six years.
Granite Production Flow
The quarry floor is currently about 40 feet below the ground surface; tests have shown there are at least 50 ft. of granite below the floor. Blasting, done by Cruickshank of Kingston, produces 36-in. minus rubble, which is fed into the primary crusher (a 3055 Pioneer) by Caterpillar 988H, while a CAT H140 breaker is used to break oversized rubble. A 6-ft. x 16-ft. scalping screen removes fines and also flat and elongated pieces that don’t meet cubicity standards. The primary crusher produces 9-in. minus product, which goes into a Sandvik S3800 gyratory secondary crusher. The 3-in. minus product is fed into a surge bin which provides a consistent flow to the tertiary Sandvik H3800, which makes a half-inch end product. A 6-ft. x 20-ft. ELRUS screen removes fines and a closed-circuit section feeds back anything too large. The spread is powered with an 1100KW generator, and shifts run 6 a.m. to 6 p.m.
|Danford spent about three and a half months in 2011 implementing the plan for the rehabilitation of a local historic talc mine.|
“Everyone in our operation is important, but our crusher operators, our crusher ‘ground’ crew and the operators who run the loaders for feeding and stockpiling/loading are critically important,” says Danford. “Your crusher operator is adjusting things continually to make sure the process produces a consistent product, but the ability of your feeder to provide the jaw with a mixture of rubble sizes is a big part of that too. Stockpiling must also be done correctly or you lose consistency there. And your ‘ground’ operators who monitor the crusher all day are key to making sure the machinery is all working properly.” Danford says that a person in that position, who is scanning continuously for things like bearing wear, can potentially save the company tens of thousands of dollars in avoided repairs and downtime on an ongoing basis.
Cruickshank generally blasts granite for Danford every five or six weeks, but the summer of 2011 was a little different – to say the least. “They actually set their biggest blasting record ever here and then they broke it and set their new record here,” says Danford. “When we asked them to do bigger blasts, they made it happen. We lose two days’ production every time we move the crusher out and in for a blast, so bigger blasts let us keep production going.” The biggest blast they have carried out involved about 660 holes.
The two limestone quarries, operated since 1995 and 2004, produce aggregates for a wide variety of purposes. “We make granular A, M, B for concrete and asphalt road bases, gabion stone for drainage, clear stone for drainage and HL3 and HL4 for surface treatments,” says Danford. In 2010, they purchased a Terex Cedar Rapids spread for use in their limestone pits and quarries. “We decided on that one because it’s more portable than some others on the market – the screen and cone are on one chassis – and the company has a good reputation and it was also ready to purchase,” says Danford. “We didn’t want to wait and we didn’t have to with this unit.” A Caterpillar 980G feeds the Elrus 2442 primary crusher, which produces 6-in. minus product. A surge feeder provides consistent flow to a closed-circuit secondary cone plant MVP280 Terex Cedar Rapids with a 6-ft. x 20-ft. screen on Masaba frames. McCloskey conveyors move the finished product. In late November, they were making granular B at 275 tonnes per hour, with a Caterpillar 966G handling stockpiling and shipping.
Danford will begin operation of another quarry (traprock) in the next year or so. “The traprock meets concrete and asphalt aggregate standards as well as Class 1 & 2 railway ballast,” says Danford. “There are reserves of 20 million tonnes.” The company held public meetings during the fall 2010 to educate the public about quarry operation. “We are committed to following all the guidelines set out by government agencies at various levels, and have good relationships with our local municipalities and citizens,” says Danford. “It’s important to us that we are good neighbours.”
Treena Hein is a freelance journalist based in Pembroke, Ont. She researched and produced this article for Aggregates & Roadbuilding.