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Large Diameter Borehole (2m dia.)
15 January 2018

We have a requirement to make a 2 metre diameter lined borehole to a depth of 200 metres to provide access to an underground mined area. Ground conditions are generally soft, not hard rock.

I am unable to find a drill rig manufacturer or source equipment able meet this requirement

Any ideas or advice will be much appreciated!

9 answer(s)
General Manager
Total Posts: 10
Join Date: 27/02/16
You can try too Micon in Germany. They have a segment dealing with mining technology.

Total Posts: 1
Join Date: 06/02/18

I'm not sure what eventually happened to all the large diameter drilling tools we were using on the Government Nuclear Repository project in Washington State in the 80's. On that project we were drilling a 144" hole to +-6500'. The Washington State project never really got going because of environmental group activities. However, the rig did stay on Std-By for around 6 years on the Government's dime. The rig in Washington was Loffland Bro's Rig #32 which had been retro-fitted to handle the bigger/heavier loads expected, after it had just finished the Deepest Hole in the World (at that time). We did get the BHA assembled and everything prepared to spud but that was the extent of the drilling operations. The project I worked on in the early 70's we drilled a 96" hole to ~ 2600' then ran 90" casing as part of a oil shale mining project here in Colorado (if I remember dates correctly). On the projects we used reverse circulation/air assist methods using 13 5/8" drill-pipe with bit's having replaceable roller cutters, stacked 90" X 4' diameter "Doughnuts" for weight (instead of Drill Collars) placed on a "Mandrel" assembly which the bit was bolted onto. I remember reading somewhere in my memory about how some mining operators actually "drilled-up" to create a shaft, instead of drilling down to do so. I have a feeling this too is highly specialized operational equipment and have no idea where to go for companies that do this work. Over my career in typical O&G drilling operations I've drilled pilot wells then opened them up to 36" using hole openers and that type of off-the-shelf equipment, but once you get much bigger than that then the tools become pretty scarce.   I will do a little research and see what I can find and hopefully get back later--Good Luck

Head of Well Engineering
State Supervision of Mines
Total Posts: 13
Join Date: 09/11/15
Offshore Newfoundland the operators usually drill a 2m hole (or larger) as a cellar to protect the wellheads from passing icebergs. Don't have any contact info though.
Well Services Manager
Sasol Ltd
Total Posts: 5
Join Date: 11/04/16


good morning.

In Germany we do a lot of large diameter drilling in ahead of the open cast mines for soft coal to dewater aquifers down to +/ 400 m deep. So that is a very common technology.

If you wish you can drop me a line and I put you in contact with a former manager at RWE for those operations (promoted higher now). I am sure he can help you.



Drilling Engineer
Genel Energy
Total Posts: 2
Join Date: 27/02/16
Try Bauer Technologies UK.

if they can’t help you, I’m pretty certain the parent company has a subsiduary that specialises in large diameter land drilling.

Drilling Specialist/Well Engineer/Training Consultant
Kingdom Drilling
Total Posts: 361
Join Date: 10/01/05

Hole openers and reamers


manufactured hole openers since 1972 from the smallest of overburden reamers to large dia specialist reamers for the construction industry.

Knowledge gained over the years has lead to working with bit manufactures to produce here in the UK reamers for the oil field industry.  

Sybe Visser
Managing Director
Swift Drilling BV
Total Posts: 1
Join Date: 18/12/17

Have a look at the webside of German Tunnelbore manufacturer Herrenknecht:

The size is too large for you however they have a lot of solutions.


Sybe Visser
Project Quality
Total Posts: 99
Join Date: 06/05/09

Absent a lot of info, it appears that what you want to be able to do is already quite common in the mining industry ... they frequently have requirements to drill into tunnels from surface.

Typically, their approach is to drill a smallish diameter pilot hole in the 8-1/2 to 12-1/4in range using conventional wireline steering tools and downhole mud motors, and then use a hole opener under tension by pulling it back to surface.

I don't have any names to give you, and you'll likely have to organize several contractors, each covering a specific task, but some research will likely get you those.

Well Engineering Consultant and Instructor
Olango Consulting
Total Posts: 21
Join Date: 23/03/16

I know that the shafts for the nuclear waste storage in the US were drilled with Foam and large diameter bits.

I have one very old paper on the subject that I have attached.

Tim Roe who is on linkedin as a WSM & DSM Training Coach at Chevron was on location doing some of this large diameter work for the nuclear waste storage in the US back in the days.

To drill a 78 inch hole you probably need to look at mining equipment and suppliers of mining bits.

Documents uploaded by user:
large Diameter Boreholes.pdf
Posted by

Philip Lock

Consultant Mechanical Engineer


Total Posts: 1
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