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Drilling technology advancing on all fronts

September 1, 2007
by Sudbury Mining Solutions Journal
In: News with 0 Comments
The following is an interview with George Demers, manager of surface coring for Boart Longyear Drilling Services. Demers began his career as a helper on a diamond drill rig 21 years ago.

He has worked for Boart Longyear for most of his career and also spent four years with Inco. Based in Haileybury, 160 kilometres north of North Bay, he oversees all surface drilling in Canada for Boart Longyear.

SMSJ: How have drill rigs changed and what impact are these changes having on drilling performance?

George Demers: The quantum leap in technology took place in the 80s going from the old conventional rigs – also known as gear jammers or direct drive rigs – to hydraulic rigs. Now the focus is on refining the hydraulic rigs for health and safety and ergonomics, but there are still a lot of conventional rigs kicking around.

If you’re working with a conventional rig, you pull the rods out using a hoist and cable in a tower structure. The helper is up on a platform handling the top of the rod and the driller handles the bottom. With the newer hydraulic rigs, there’s no tower and no platform up in the air. There’s a hydraulic rod handler, also called a manipulator. So there’s a set of controls for the driller and a set of controls for the helper. You’re not subjecting the helper to being perched 30 feet in the air, especially in winter conditions.

SMSJ: Why are there so many gear jammers still in use?

GD: There’s such a high demand. People are scrounging to put rigs out in the field and the manufacturers can’t produce them fast enough.

SMSJ: What’s happening as far as automation is concerned?

GD: On surface, there is no automation taking place. Underground, however, automation is at the forefront. At Inco, the entire fleet of diamond drills is automated. They work single man. Essentially, the man is there to help the process along. The computer does the drilling.

SMSJ: Why is automation being accepted underground, but not on surface?

GD: When you’re going out to grass roots, greenfield exploration, you are sometimes 500 kilometres from anywhere, so you need something that’s reliable. You’re crashing through the bush. There’s a lot of vibration.

SMSJ: What are the pros and cons of automation?

GD: Once automation takes off, it will improve productivity. The computer can drill while nobody’s there. There are sensors on the feed rate, penetration rate sensors, weight sensors and flow meters for the water to cool the bit. The programmer needs to virtually be a driller and the driller has to be somewhat computer savvy so he can add the mins and maxes on each parameter for different types of ground. Then the computer will do everything it has to do to keep the mins and maxes in range. If one goes higher or lower, it will adjust another one. It will literally drill by itself. Once it’s blocked, it will stop. But you still need an operator because drilling represents only 60 per cent of the drilling cycle. The other 40 per cent is physical labour that the computer can’t do.

SMSJ: How will automation affect drilling performance?

GD:  I tend to believe that automation will make a poor driller better. It will essentially make every driller an average driller, but there’s still no replacement for the highballer, the guy who is always riding the razor’s edge, pulling 102 per cent out of the rig. With the computer, you build in some risk factors and because of that you’re getting maybe 90 per cent. At the end of the day though, you’re still better off.

SMSJ: How is technology evolving to steer holes in the desired direction?

GD: Navi drilling is still used today to direct holes. It’s not foolproof by any means. It’s very finicky with regard to the type of ground you can use it in and the results aren’t predictable. Devico drilling is a product that’s been around for 10 years, but it’s still being refined. It has proven reliable down to depths of 1,000 metres. It has also been used down to depths of up to 2,000 metres, but not with a predictable result. We have a few production rigs that use it consistently in the Athabaska Basin of northern Saskatchewan. We use it periodically in the Sudbury Basin and we have used it in the Red Lake camp. Wedging is the traditional method of directional drilling and it’s still used today. There are also collapsible, or retrievable, wedges. They will only give you a one and a half degree deviation, but on the plus side, there’s no steel in the hole.

Some rock formations are easier to steer holes in than others. Mother nature works in mysterious ways. In some places, you can spend a huge amount of time, money, effort and resources on steering holes for no other reason than Mother Nature does not want you to go that way.

SMSJ: How are drill rods changing?

GD: Drill rods have come a long way in the last few decades. Primarily with respect to materials. Quality has improved dramatically. We’re getting a much tougher rod joint that doesn’t wear out from all the screwing and unscrewing that takes place when you’re tripping rods out to change the bit. If the rod is properly mated and torqued, the joint is actually stronger than the mid-body of the rod.

SMSJ: Efficient drill core recovery is also important. What’s happening there?

GD: Like I said, only 60 per cent of the drilling cycle is actually drilling.  Whenever the drill isn’t turning, you’re not making money, so there’s huge R&D money being spent to cut that 40 per cent. The pet peeve of all contractors is the time it takes to cycle an inner tube. The inner tube fits very tightly inside the rods, so you have this empty core tube to go down. And because it’s empty, it’s light. It has to displace the water, so it takes time, especially if it has to go down two kilometers. There’s all kinds of research being done on this.

SMSJ: What’s new and exciting with regard to bit technology?

GD: Drill bits have improved a lot. Once again, time is money in this business. Every time you stop drilling because the bit’s finished, you have to pull the rods out. Sometimes, in deep holes, you have to stop drilling for a day or two to change the bit. All bit manufacturers are working on making longer crowns. The problem with that historically has been that the longer the crown, the weaker it is. Every manufacturer has its own design to make the crown longer and extend the life of the bit. Boart Longyear’s Stage 3 bit is a perfect example. Boart Longyear Drilling Services was at the forefront of the R&D on that.

Given the proper bit with the right operator at the controls, we’ve had bits go in excess of 1,000 metres, but we’ve also had bits go 20 metres. Sometimes it’s the wrong bit for the ground conditions, but, let’s face it, in this market there are a lot of inexperienced drillers. You can also have a lack of water or a bad rod. If a rod springs a leak, the coolant doesn’t make it down to the bottom of the hole and you burn the bit.

SMSJ: How is Boart Longyear coping with the skill shortages plaguing the mining industry?

GD: Training is a huge factor. We have a drill school in Haileybury.  Recruits spend two weeks in drill school and then one week as a third man on an operating rig in the field before they go out. Twenty-one years ago when I started out, it was, “There you go, George. Here’s your driller. Have fun.” It was cold turkey. So we’ve come a long way.

SMSJ: Has concern for the environment affected how drilling is done?

GD: It’s huge. Boart Longyear is ISO 14001 accredited. We’re also OHSAS 18001 accredited. It acknowledges that we have programs, systems and equipment to not only deal with a spill, but also to prevent a spill in the first place. Some clients will not hire contractors that don’t have the proper systems in place.

Containment of the water and cuttings is also an issue. As proprietary as the work is, the client has to divulge what we’re drilling for. Gold, for example, is often associated with arsenic. If it’s a virgin hole, we’ll make a sump to contain the cuttings until we can confirm if there’s a hazard. They settle in a controlled environment close to the hole so they don’t get into the environment. Uranium poses an immediate and lethal threat, so you can’t let the water flow on the ground. The water and cuttings are collected, packaged and disposed of at proper facilities.

SMSJ: It’s really amazing when you think about the skill and technology associated with drilling a three inch diameter hole two or three kilometers through solid rock and collecting all that core.

GD: The age old question about diamond drilling is if it’s a science or an art. There’s a lot of science involved, but at the end of the day, diamond drilling has a lot to do with the skill, intuition and creativity of the driller.

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