Today I'm at the Stanton Landslide near Waiau and here behind me you can see a drilling rig
and so I'm about to talk to James Chapman who is the managing director of CW Drill.
James is going to show me how this little drill rig works. And basically they're drilling through
the landslide to find out scientifically how it looks underground. So the the inside
of a landslide. The landslide came down from the Kaikōura earthquake about five years ago,
and so studying the landslide will teach the scientists a lot about what sort of triggers might
have caused the landslide, how much earthquake shaking, and maybe the results of
subsequent rainfall events - how they impact on the landslide and all sorts of things like that.
But James is going to show me the technology used in the drill and how they recover the
core of material and bring it to the surface. Okay so this is a multi-purpose drill rig,
so it's capable of doing many things. So this particular job is PQ coring through the landslide.
So it involves taking core samples from the surface to a predetermined depth
to understand a bit about the geology that's happening in the ground.
So what we have is a tubular drilling system, so we're running a triple tube system, so this is a
tungsten carbide drill bit for drilling soft formations. So this is a soft formation
landslide at this stage, so it's not particularly technical drilling but it is very hard to recover
the core because it doesn't behave very well. Rght so it's very muddy, it doesn't stay together.
It's very muddy and it's very slippery - it likes to just fall out the end of the tube.
Okay how do you capture it and bring it up then? And then we'll come over here...
Okay so we have a diamond drill bit or a bit that spins quite quickly and cuts the formation. The
core runs through the out through the middle of the bit and we have... Okay so that's this way
up? Yep that's that way. Rotating? Yep - so it's rotating and cuts the material then we have a bit
of trickery called an inner tube. This is an inner tube so this guy slides down and locks into that
guy, and on the end of the inner tube we have our lifter in our lifter case. So this guy here
he's tapered, he's tapered and the inside of this guy is tapered so as the rock you've cut
goes up inside it stays in there and when you want to come off the bottom the two tapers pull
together this guy comes in. - and they kind of shrink? Yep shrinks in and grabs hold of
the the core that you've cut. So our core once you've cut it runs up inside this guy
until we've got a (hopefully) a full tube and then we extract it using a wire line. So we send a wire
line down the hole, it locks into the back of this guy up here, and then we extract the core.
Then we put a new inner tube back on - Yep - and send it down the hole and lock it in
place and then we continue drilling. And so the the core is then extracted from the inner tube
here on the spot? Yes so we do that here yes. Okay and then put in a box and so you've got
an extra one so you can swap them out quickly. Yes i'm starting to get it!. Cool [laughs]
Yeah copy Darren So we've just got a helicopter arriving
Okay so we know how the core gets captured and brought up, maybe you could show me a little
bit about the rig? Okay so there's the mast. Yep the mast, we have a rotary drill head
that goes round around. So to drill a hole we need three things: we need the ability to pull or push
the machine down, we need the ability to rotate and we have to have a cleaning medium of some
sort. So whether it be air, foam, water or other products to assist with that process. You have to
clear your cuttings out of the hole whether it be using one of those mediums. Yeah, okay.
How long is a piece a section? We're running three meter tool joints, so three meter pipes.
So basically we're drilling in three meter sections and drilling one point five or
one to one point five meters at a time. Nice system! Portable, mobile... Portable, mobile,
it's on tracks. You must have a great big warehouse somewhere full of bits of drills
where's that? 13 rigs it's in Motueka, we're Motueka based. Right. so we cover
most of the south island so we've got machines in Auckland, we've got them all over the country,
so they're doing this type of thing. Right. So we have a an interesting, challenging lifestyle,
in the aspect that we - where we get to see a large part of New Zealand that a lot of
New Zealanders don't actually see much of the time, so it's fantastic. Great thanks for that!