DRILLING TECHNIQUE

Dominion, Volume 37, Issue 237, 4 July 1944, Page 3

DRILLING TECHNIQUE

Latest Developments In United States STUDY BY NEW ZEALAND EXPERT The iuienl.iou ot the Govornincnt to send the drill siiperiiilciideut on the stalt of the .Mines Deparuncul, Mr. J>. -McMillan, to (he United States, to study-the latest developments in drilling equipment and technique, and to advise the Governuicut as to (lie most, suitable type ol drilling plant, required in the Dominion, was announced last night, by the .Minister of Mines, Mr. Webb, lie said that Mr. McMillan had a -wide knowledge of conditious of drilling in this country, and recent geological wdik had shown that a very large amount of relatively deep drilling was required. . "Our owu experience and llmt or me experts associated with the search tor oil in New Zealand," said Mr. M ebb, • has shown that deep drilling ,is a very liilti* cult and intricate matter, and only the most modern plant is likely to succeed in such work. It is known that great progress has been made in tuO: United States in what is called •shm-hole drilling to 5000 feet, nud the Government is definitely of opinion that its expert should study the methods adopted in that country.” ’ , . , ... .Referring tu the geological work on Hit study of the Dominion’s coal resources, the Minister said that this was inaugurated in 1936. and as the result ot the work carried out to date, a very extensive boring programme had been mapped out. it recent bore-bole at Dobson had penetrated a coal seam 10ft. Sin. thick at a depth of 1300 feet. It was good bard eon), and the bore hole was located about 15 ebains ahead of the dip-workings in the present Dobson colliery. Ihe discovery of workable coal at (his point opened up possibilities of proving a held of bituminous coal between Dobson and Greymouth, but due tc the depth of the coal measures from the surface from 1500 to 2000 feet—a substantial area would have to be proved to make it economical to open up a new colliery by the sinking of two deep shafts from the surface. Department's Future Policy. The department’s future policy in respect to the working of the Dobson colliery was clearly dependent on the extent of the area of coal ahead of the present workings,' and further drilling would be carried out with the utmost speed to enable this policy to be determined. "The discovery of a new field of bituminous- coal near Dobson will be of great benefit to the Dominion, said Mr. Webb, "as our existing resources of good bituminous coal are very limited iudccd. An interesting feature in connexion with the Dobson bore-hole just referred to is that it lias disclosed the presence of oil iu small quantities. The Mines Department's-officers are in touch with oil experts to ascertain the true significance of this discovery.” In the meantime, said the Minister, it would be unwise to over-estimate _ its significance. He pointed out that a similar discovery was* made from a bore-hole sunk in the vicinity in 1903. No attempt was made at that time to ascertain the true value of the oil discovered iu tile bore-hole, but a geologist expressed (lie opinion that the occurrence was probably <i local one such as bad in. a tew instances been reported in connexion with coal-bearing rocks in various parts of the world. Should that prove to be Ihe case it would have no economic importance.

Tim Minister said that drilling at the Liverpool colliery bnd been continued to n. depth of over 1600 feet, and _ at 1500 feet a seam of coal Oft. -lin. thick, divided by a band of shale Ift bin. thick, had been cut. The discovery of coal at this depth was a very encouraging factor, but due to the geological conditions in this area, it was not. possible to give a precise valuation to the discovery I ill further drilling had been carried out, and the data so obtained scientifically interpreted.