PARITUTU.

Taranaki Daily News, 11 June 1921, Page 5

PARITUTU.

QUALITY OF THE STONE. A FAVORABLE REPORT. OPINION OF CONSULTING ENGINEER. SECOND BLAST DEFERRED. A report on the quality of the Paritutu stone, and also referring generally as to the most suitable sources of supply, was received by the New Plymouth Harbor Board yesterday from the consulting engineer (Mr. J. Blair Mason). After reyiewing the question at length, Mr. Blair. Mason expressed the opinion that to carry the board’s works on expeditiously the Moturoa Island quarries would have to be worked in conjunction with a stone supply ashore, for which Paritutu was the only available economical source.

The chairman of the board (Mr. Newton King) remarked that the report spoke for itself, and that Paritutu stone was very suitable for the purposes in view.

Mr. C. E. Bellringer said that the second drive was now being put in, and he presumed it would be gone on with. The chairman: There is no authority given for that yet. In reply to a question, the engineer (Mr. G. W. Baxter Lowson) stated the blast would be ready to fire in about a fortnight.

Mr. C. A. Wilkinson asked if any reply was to be forwarded to the deputation which waited on the board from the Paritutu Preservation League. The chairman replied that it had been arranged that the preliminary work in connection with the tram-line to Paritutu should be continued, but the question of blasting would be deferred until after the next meeting of the board (on the second Tuesday in July). The report from the consulting engineer stated:—“l examined Paritutu on May 9 and 25, and noted the quality and approximate quantity of the stune brought down by the recent blast. Reconsideration has also been given to the general question of stone supply, which was discussed in my report to the board 01 1918. In order to make clear the relationship of stone supply to the progressive order of the harbor works, as well as to the character of these works, I may be pardoned in altering the -sequence of your instructions and making a few introductory remarks thereon SOURCES OF STONE. “My report of 1918, which the board duly adopted, recommended the Motu-roa-breakwater wall and the breakwater extension as the first and essential works, and of urgent necessity in order to provide assured shelter for* vessels in all weather conditions, also .additional berthage by rendering available the use' of the breakwater as originally intended by Sir John Coode. This latter result was to be effected by stopping the sand drift round the end of the existing breakwater by the interposing of the breakwater wall. The sands so stopped were to be allowed to accumulate behind the breakwater wall, .and not only constitute a barrier against the seas flooding or breaking over the waljf but provide the reclaimed lands so vitafly necessary to meet the requirements of the port. “In contemplation of the works of today, such as the Moturoa-breakwater wall and the breakwater extension, the stone supply had to receive first attention. It was evident that the Fishing Rock quarry could not supply sufficient stone for all the proposed works, also that the stone was shivered and could not be broken out in large masses. Therefore the extension of the breakwater, pending the completion of the Moturoa-breakwater wall, opening a supply of large rubble frdm Moturoa Island, would have to follow the large monolithic and concrete design. “In the conception of the works it was evident, granted the rock was suitable, that the connection of Moturoa Island to the, breakwater by means of the fundamentally important wall, would assure to the board an adequate stone supply /foi the breakwater purposes. The initial examination of Moturoa Island stone and the indications as revealed by the tunnels driven, showed the stone to be of high specific gravity, and that when the overburden was removed, a compact heavy trachyte would be available, promising a sufficiency of large blocks for the sea faces of the walls. In May, 1919, the board were in a position to proceed with the work of opening out Moturoa quarry with the view of getting stone to speed up the Moturoa and breakwater walls. Unfortunately, the impossibiliy of securing the necessary labor, plant and materials, owing to post-war conditions, compelled the shutting down of the Moturoa quai’Vy works and concentrating the little later available on the Fishing Rock quarry, from whence the stone could be barged on the breakwater wall by the Thomas King, which had been converted into a stone barge, as no Vessels suitable for the purpose were available. TO SPEED UP WORKS. “The board are now under the necessity of providing for the unprecedented increase, in the trade of the port, for which the existing berthage accommodation is totally inadequate, and which cannot satisfactorily be provided for until .the breakwater and Moturoa walls are further advanced. Under the existing conditions, an immediate speeding up is only possible by increasing the output of stone from the shore. The Fishing Rock quarry is practically exhausted, and there only remains to the board the choice of getting stone from sources more or less remote and expensive, such as the Government quarry at Mount. Egmont or of utilising the stone, if suitable, from Paritutu.” The report proceeds to deal with the geological nature of the stone, and after quoting figures as to specific gravity Mr. Mason states:

“It will be seen that in weight the Paritutu stone compares favorably with Fishing Rock stone, while Moturoa is somewhat heavier than either. All, however, are suitable in durability for marine works.

“It is important that in the foimation of a rubble mound breakwater the stone should not only be durable, but obtainable in masses up to 30 tons for the exposed parte of the breakwater. The percentages in the sizes of the stone recently brought down by Paritutu in blasting, are estimated as follows: Rubble stone 2 tons to 30 tons, 20 per cent.; to 2 tons, 30 per cent.: % cwt. to 10 cwt., 35 per cent.; under i cwt., 15 per cent.; total, 100 per cent. The total stone dislodged by the ex-

plosion is estimated at 30,000 tons, all of which rock can be used in the works, with a sufficiency of large stone for tho exposed places of the mound.

SUITABILITY OF PARITUTU. “I am of opinion that the above proportion of large stone of good quality can be maintained at the Paritutu quarry, a proportion adequate and suitable for building up the proposed breaks water extension in a stable and satisfactory manner. The work done in opening up the quarries at Moturoa and Paritutu show that the board possess at both places ample supplies of rubble suitable for the construction of sea walls, and of concrete work generally. The Moturoa stone can not be economically transported or barged for breakwater extension and stone works until some progress has been made with the projection of the Moturoa-breakwater wall from the island, under the shelter of which the barges would load the stone. Given the completion of the above Wall, Moturoa quarry would afford ample supplies of high-class stone for the board’s works conveniently situ* ated and placed for getting and transporting at a minimum cost. “For the early completion of the breakwater extension, it will be plain that Moturoa stone cannot be imme< diately available, and Paritutu alone comes the source from which, without delay, a satisfactory supply of suitable stone can be obtained at a low cost. l£ will be apparent that remembering the need and cry for increased berthage accommodation and shelter to meet the rapidly increasing trade, the board ift compelled tb expedite the Moturoa wall and breakwater extension by every, means at command. To carry these work* concurrently, and with the despatch essary to meet the situation* reqtthmjk that the Moturoa Island worked in conjunction with a ply ashore, for which only available economical