THE HARBOR.

Taranaki Daily News, 18 October 1919, Page 3

THE HARBOR.

THE EXTENSION WORKS. OFFICIAL INAUGURATION. Those who went to the breakwater yesterday afternoon- to see the Island of Moturoa cast into the sea were doubtless disappointed. Nevertheless the inaugural explosion in connection with the work of extending and improving the harbor, was, from the Board's pomi of view,-entirely successful. Interest in the occasion was evideiit from the large numbers of people who wended their way toward the breakwater as the time of the explosion approached, and by 3 o'clock there was a large gathering of people about the wharf and on the various vantage points about the harbor. Those who took up their position on Mikotahi or further round towards Paritutu had the best view of tiie explosion; though the dislodgment of rock was not expected by those closely connected with the undertaking to be a very spectacular event. The tunnel was bored into very hard rock on the southwestward side of the island. The dimensions were oft high by 4ft wide, with a length of 24ft. At the end of the tunnel there was an L-end chamber, Bft by. 3ft by 4ft., which contained the explosives. The chamber was charged with 15 cases (equal to 7501b5.) of Noble's gelatine dynamite, stacked close up to the face. At the back of the explosives a concrete wall was built to hold the charge in position. The remaining portion of the tunnel was firmly packed with quarry refuse, and sealed at the' mouth with concrete. Special submarine detonators were used to ignite the charge. The wires from the detonators were brought out to the face of the tunnel through a pipe and from, there were connected to a twin cable which was concreted with the firing station in another tunnel on the opposite side oi the island, and at a higher altitude than that in which yesterday's charge was placed. The mouth of the tunnel was about 30ft above high water mark, and the overburden was approximately 40ft. The amount of rock dislodged was estimated by the engineer to be in the vicinity of 400 tons. The cost of driving the tunnel was about £2 10s per lineal foot, but it is expected that the price of future tunnels will be -mucli reduced owing to better facilities lor working, and also housing the employees. Two shifts of men have been engaged on the work of making the tunnel almost the whole time since it was commenced.

The arrangements foi firing tho charge were changed at the last moment yesterday, and instead of it being done by the chairman of the board it was carried out by a member of the party which went on to the island with Mr. Lee, the engineer. About 2 o'clock, Mr,. Lee, With three press representatives, Mr. A. L. Moore, Principal of the New Plvmouth Technical College, and some of the Harbor Board's employees went over to the island, and the visitors were shown over the work that has been done and also conducted to the mouth of the tunnel in which the explosives had been placed for yesterday's ev-ent. They afterward? returned to the tunnel which is being made on the shoreward side of the island, to which the coil had been carried, Riid where it was connected to the battery which was to "do the trick." At one minute to three a signal was sent to the shore, and the crane whistle called everyone's attention to the fact that ;he time for the explosion had arrived and promptly at 3 o'clock the mine was exploded, the honor of "pressing the button," was given to Mr. Moore, of the Technical College. Those' inside the tunnel where the battery was heard nothing but a dull roar, 'and felt only the slightest vibration. An inspection of the locality afterwards was made by those on the island, they having to go right round by the northward side. Mr. Lee expressed himself as thoroughly well satisfied with the result. The rock had fallen in the desired direction and laid the foundation for that which will be sent after it in the near future, in the process of connecting tip Moturoa and the Lion Rock. Some of the lighter material on the surface of the shoulder that was blown away was thrown right over, and fell in the sea on the northward side of the island.

Some members of the Harbor Board, with several friends were taken round the island-in the board's launch after the explosion. Yesterday's shot was considered a small one, and was only intended to remove a shoulder of rock just above high frater mark which interfered with the future forking of the quarry. It is proposed to put a large shot near the top of the hill for the purpose of filling the gap between Moturoa Island and the Lion Rock.

Later on a charge will be exploded with a view to commencing the work of forming the wall between Moturoa and the breakwater. This will doubtless be a much more spectacular event than yesterday's explosion.