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DIAMOND DRILLING FOR FOUNDATION EXPLORATION-Moye

Diamond Drilling for Foundation Exploration

By D. G. Moye, B.Sc
(non-member)*

Introduction

Diamond core drilling, in spite of its very high cost, is very widely used for subsurface exploration for sites of dams, tunnels and other major engineering structures, when these are in rock. There is no adequate substitute for diamond drilling, although it can, and usually should be supplemented by other kinds of exploration. Although diamond drilling is widely used it is far from being a standardised procedure and many details of the planning, execution and evaluation of the diamond drilling programmes need careful and systematic attention to obtain the best results.

The procedures used for geological investigations in the Snowy Mountains Scheme have been described in outline previously (Ref. 1). The purpose of this paper is to give details of current procedures in diamond drilling, including modifications introduced as a result of experience.

Planning the Drilling Programme

Details of planning vary greatly with the type of project and whether the project is in the preliminary investigation or the detailed design stage, but the same general principles apply.

First the engineering objectives of the exploration programme are defined.

Then an exploration programme is drawn up taking into account all geological information available at the time. Drilling is only one form of exploration which must be co-ordinated with geological mapping, sub-surface exploration by trenching, test pits, adits, etc., and by geophysical methods, especially seismic refraction. In particular it is always highly desirable that topographical and geological mapping should precede diamond drilling.

The objectives of the programme seldom remain constant in all details, being modified as the engineering studies develop and also as the results of exploration become progressively available. Care is taken to inform the field staff promptly of any changes in objectives which may require changes in exploration targets. Conversely, results from the field are relayed back to the investigation or design engineers as soon as they become available.

For the efficient deployment of diamond drilling crews and equipment it is necessary to estimate the total quantity of drilling, the number and depth of holes, their approximate locations, and special requirements. However, within these limits, the greatest degree of freedom is maintained as the drilling progresses to modify the programme to take into account any changes in engineering and geological objectives. In terms of useful information obtained it can be very wasteful and inefficient to draw up, in advance, a large detailed drilling programme and to adhere to it rigidly, although this I certainly would facilitate the drilling operations.

The site of each hole is marked out on the ground by the geologist who is expected to modify the position and slope from those given on the programme if local topography or geological conditions should make this desirable. The geologist then draws up a specification for the hole. This consists of a large scale plan and section through the hole, and a written specification which includes a statement of the engineering objectives, the geological objectives, the anticipated drilling conditions (rock types, faults, etc.) and any special requirements. The specification is reviewed by the engineers concerned and then given to the drillers.

*Paper No. 2150, originally presented before The Institution's Site Investigation Symposium, held in Sydney on 1st and 2nd September, 1966.

The author was formerly Head, Engineering Geology Branch, Snowy Mountains Hydro-electric Authority and is presently Director of Exploration, The Broken Hill Propriety Co. Ltd., Melbourne.

Details for this article:

Diamond Drilling for Foundation Exploration

X

Author: Moye, D.G. (1967)

Article Title: Diamond drilling for foundation exploration. Paper 2150 presented at I. E. Aust. Site Investigation Symposium, September 1966.

From: Civil Engineering Transactions, April, 1967

Other Available Articles

Engineering geology for the Snowy Mountains Scheme

Moye, D.G. (1955)

Engineering geology for the Snowy Mountains Scheme.

J.I.E.Aust., Vol. 27 No.10 pp287–298

Rock Mechanics in the Investigation and Construction of T.1 Underground Power Station, Snowy Mountains, Australia

Moye, D.G. (1958)

Rock Mechanics in the Investigation and Construction of T.1 Underground Power Station, Snowy Mountains, Australia

In Engineering Geology Case Histories No.3 123–54 Geological Society of America 69 (12) p.1617

Existence of high horizontal rock stresses in rock masses.

Moye, D.G. (1962)

Existence of high horizontal rock stresses in rock masses.

Proc. Third Australia-New Zealand Conference on Soil Mechanics and Foundation Engineering. pp 19–22

Seismic Activity in the Snowy Mountains Region and its Relationship to Geological Structures

J. R. Cleary, H. A. Doyle, D. G. Moye (1964)

SEISMIC ACTIVITY IN THE SNOWY MOUNTAINS REGION AND ITS RELATIONSHIP TO GEOLOGICAL STRUCTURES

Journal of the Geological Society of Australia

Unstable rock and its treatment in the Snowy Mountains Scheme.

Moye, D.G. (1965)

Unstable rock and its treatment in the Snowy Mountains Scheme.

Proc. 8th Commonwealth Mining and Metallurgical Congress, Australia & New Zealand. Vol. 6, p. 423–441.

Diamond drilling for foundation exploration

Moye, D.G. (1967)

Diamond drilling for foundation exploration.

Paper 2150 presented at I.E.Aust. Site Investigation Symposium, September 1966. In Civil Engineering Transactions, with Discussion, April 1967.

Geology in Practice

Moye, D.G. (1970)

Geology in Practice. Presidential Address Section 3, Geology, ANZAAS Meeting.

Australian Journal of Science, 32 (12) June, p454–461.

* This paper was presented when Dan had been Director of Exploration of BHP for 3 years.

Field and Laboratory Tests in Rock Mechanics

Alexander, L. G (1960)

Field and Laboratory Tests in Rock Mechanics

Proceedings, 3rd Australian-New Zealand Conference on Soil Mechanics and Foundation Engineering, Sydney Australia, 1960, pp. 161–168.

Discussion at Technical Session No. 9—Rock Mechanics

Alexander, L. G. Moye, D. G. (1960)

Discussion at Technical Session No. 9—Rock Mechanics

Proceedings, 3rd Australian-New Zealand Conference on Soil Mechanics and Foundation Engineering, Sydney Australia, 1960, pp. 254–250