DEEPENING THE HARBOR.

Oamaru Mail, Volume IV, Issue 983, 13 June 1879, Page 2

DEEPENING THE HARBOR.

4t the meeting of the Harbor Board to-day, the Secretary (Mr. Forrester), in response to a request from the Chairman, gave an interim report of the result of the borings which have taken place lately at the port, with a view of ascertaining the feasibility of deepening the harbo.f, Mr. Forrester said j I have muoh pleasure in acquainting you with the result of the trial borings now being made in the harbor, with a view to testing the practicability of obtaining deeper water than could be got above the natural bottom by excavating or dredging. Three borings have been made within a radius of sixty feet from a point about two feet from the present end of. the Breakwater. The surface consists of a layer of sand, from one to two feet in thickness, which being removed exposes the hard surface of a shingly conglomerate forming the bottom. It has hitherto been found impossible to j penetrate this crust or layer with the steel-pointed tools used to try the depth of the sand or mud deposited on the bottom, and was therefore deemed to be a continuation of the trap reef forming the bed of the shore, from |the low water upwards. In the trials made, this hard- bottom consists of shingle firmly impacted in indurated mud, so well united that the diver has great difficulty in removing pieces of the shingle from its bed, and from its nature it is difficult to penetrate with boring tools ; but once penetrated, and a face obtained, there will be no difficulty in loosening and removing it in pieces. It appears to be about two feet in thickness, and overlies a thich stratum of hard, tenacious mud, presenting the appearance of soft shale. This stratum has been penetrated to the depth of fourteen feet without change (this being the utmost depth obtainable with our present tools), and is uniform in all the trial holes. The experiments are being continued nearer the end of the Breakwater, the result of which will be communicated in due course. So far as the trials have gqne, they point to the possibility of dredging easily to any required depth, and, so far as I can see, without the use of explosive compounds. The statement was received with marks of strong approval, and on the motion of Mr. Steward, seconded by Mr. Menlove, it was resolved, " That the Board expresses its satisfaction at the information contained in Mr. Forrester's report, and minutes its thanks to that gentleman for the intelligent pains taken by him in the Board's interests, and directs that sufficient borings be made to enable a complete report to be prepared."