It pinches off the flow of high-pressure water used in the drilling process and changes its direction to push the core tube up the drill rods.
When not in use, the annular pinch valve can be retracted from contact with the rotating drill rods.
They have also invented a new multi-latch head assembly so the core tubes can be unlatched using water pressure.
CVRD Inco provided funds for the product development and did some testing at its facilities.
The traditional core tube retrieval process is comparable to fishing, he said.
Once the core tube is full, the driller has to stop what he’s doing, send a long wire cable down inside the rods to the bottom of the hole, where it physically locks onto the core tube and is pulled to the surface.
“Your production time is divided between drilling and retrieving core,” said Clarke. “The more efficient you can make recovering the core, the more time you can spend drilling, which is what you want to do.”
The annular pinch valve can also be used to remove water from the drill hole, which speeds up the descent of empty core tubes.
Other companies have worked with using water pressure to retrieve core tubes in the past, but Clarke has solved at least one problem associated with the process.
The annular pinch valve ensures the seal does not come in contact with the rotating drill rods and wear out, something which has traditionally been a problem, said Clarke.
The system is not yet ready for purchase because it is still being refined, he said.
Once that’s done, he wants to find another company to partner with to produce and market the core retrieval system around the world.
One of the conditions for this partnership will be that the devices are manufactured in the Sudbury area.
Three prototypes of the system were put together at B & D Manufacturing in Sudbury.
The product will sell well once it gets some exposure, even though diamond drillers are used to traditional methods, he said.
Clarke, who retired from CVRD Inco in 1992 after 30 years of service, started Dallys Industrial Services in 1996. The company focuses on products for the diamond drilling industry.
When not working on the core retrieval system, the company manufactures and distributes products like probe anchors, lubricants, grout plugs, safety plugs, inner tube vice grips, double inner tube vice grips, casing plugs and absorbent material to prevent chemical spills.
One of Clarke’s sons, David, manages Dallys, and his brother Duane is in charge of sales. Dallys’ main plant is in Falconbridge (north of Sudbury) and there is a satellite location in Haileybury.
The probe anchor product has been particularly successful, selling throughout Canada, the United States and even in South Africa, said Clarke.
“When they drill the hole, they want to send an electronic probe down to see the geophysics, but they need an anchor to hold the rope which is holding this probe,” he said.
“We developed an anchoring system. As far as I know, we are the sole manufacturers of this. It’s not a very big market, though, because it’s only the big companies that do a lot of probing. The small companies don’t have the money to do it.”
It’s definitely a good time to be a supplier for the diamond drilling industry, said Clarke.
“Phenomenal, exemplary. It’s just been out of this world. The exploration drilling world cannot get any busier than it is now,” he said.
“We can’t really keep up with the orders. I think it’s probably going to be another three years before the metal market settles down.”