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Engineering Geology for the Snowy Mountains Scheme

Fig. 6.—Packer for Water Pressure Testing

Fig. 6.—Packer for Water Pressure Testing

Electric Logging—Drill holes are logged after drilling has been completed by means of a single-electrode electric logger. An electrode is lowered down the hole and a recording instrument at the surface plots two curves showing changes in the electrical resistivity of the rock forming the walls of the hole, and changes of self potential, respectively, against depth, on a scale of 1 inch : 10 feet. Use of this method of drill hole logging was prompted by the example of the petroleum industry, where it is now common practice to make electric logs as well as gamma-ray and neutron logs, of holes put down for petroleum. The methods are described in many publications (Ref. 4). As used in the Snowy Mountains, electric logging can be applied only to uncased sections of the drill hole full of water. It is very rapid. Several hundreds of feet can be logged in less than an hour.

Fresh solid granite possesses high resistivity. Considerably lower resistivity is shown by weathered granite, crushed granite such as occurs along faults, clay seams, and closely jointed zones.

Where these occur in otherwise fresh solid granite they show up in the electrical resistivity curve as deflections towards the low resistivity side of the graph (Fig. 7). Other hard rocks behave similarly. Thus the electrical resistivity log can indicate the presence of weak zones and defects.

The greatest value of electric logging is in holes where drill core has been lost, where it provides a basis for judging the reasons for the core losses. Logging of holes with high or complete core recovery is worth while since this provides experience for interpreting electric logs of holes where core has been lost.

The satisfactory interpretation of the self-potential logs has not yet been achieved. These logs show the potentials of natural earth currents.

Water-pressure testing and electrical logging provide in- dependent sets of data concerning the rock penetrated by the drill hole.

Details for this article:

Engineering Geology for the Snowy Mountains Scheme

X

Author: Moye, D. G (1955)

Article Title: Engineering Geology for the Snowy Mountains Scheme

From: J.I.E.Aust., Vol. 27 No.10 pp287-298

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