WAIHI GOLDFIELD AREA

New Zealand Herald, Volume LXX, Issue 21561, 4 August 1933, Page 11

WAIHI GOLDFIELD AREA

GEOPHYSICAL SURVEY URGED CONFERENCE TO BE HELD [by TELEGRAPH —OWN correspondent] WAIHI, Thursday Following representations made by the Mayor, Mr. W. M. Wallnutt, as chairman of the Waihi Prospecting Association, on the importance of having a geophysical survey made of the Waihi goldfield, the Hon. E. A. Ransom, acting-Minister in charge of the Department of Scientific and Industrial Research, has advised that negotiations are in progress with the Waihi Gold Mining Company on the subject. The Minister states that the advisability of a survey of the district will be discussed at a consultation between the secretary of the department, Dr. E. Marsden, the director of the Geological Survey, Dr. J. Henderson, and mine officials. Should a survey be decided upon, the report will be awaited with great interest, as geologists have pointed to the probabio existence about these parts of "buried goldfields." Expert opinion is that the most interesting thing to do would be to divine the boundary of the probable area of the old surface of the reef-bearing quartz andesite on the field. This, as is well known, has been buried except for the two«>outcrops of the Martha and Union hills, by subsequent flows of volcanic rock, which it is believed are not reufbearing. The depth of this overburden varies greatly in different parts. For example, the Grand Junction main shaft passed through about 400 ft. of barren country and the old consolidated shaft further east was sunk to a depth of 1000 ft. and probably did not reach the reef-bearing quartz andesite. Between the Martha and Union hills, an old valley must exist filled in with this material, comprising a flow of nonauriferous andesite covered by the rather remarkable rhyolitic tuff known as wilsonite. By geophysical methods, it woidd be possible to locate th£ old surface and should a survey indicate that a peak of reef-bearing andesite approaches closely to the surface at any point, say, for example, on the Waihi Plains, this might justify intensive prospecting in the locality 'by boring or otherwise.

Tho presence of a peak would probably indicate the co-existence of enclosed quartz reefs, as in the case of tho Martha and Union peaks, which owe their presence to the resistance of denudation offered by the outr cropping quartz.