N.Z. Sandstone for Building

Progress, Volume VI, Issue 12, 2 October 1911, Page 837

N.Z. Sandstone for Building

Professor Speight, in his article on Building Stones of New Zealand in our August number, says that "the chief desideratum for building purposes, is a really satisfactory sandstone, such as the Ilawkesbury stone, used so freely in Sydney and even occasionally in this country. The best that we possess is probably that got from Dobson, near Greymouth. It is of a fine greyish colour, is easy to work, can be obtained in large flawless blocks, and the amount available is in all probability very great." He goes on to say that it is early yet to speak of its weathering qualities, although it has lasted very well in some situations. We append some tests made by Prof. Scott, M. Inst. C.E. of Canterbury, from which it will be seen that the stone is of more than ordinary strength and durability, and compares most favourably with the Ilawkesbury or the best known English building sandstones. Two pictures are shown herewith, the upper one being of part of the Dobson Building and Monumental Stone Co.'s plant and engine-room staff. The lower is of one of their three quarries, showing the stone in the face of the cut and the sheer legs and tackle used for lifting the rough stone on to the trucks to take to the cutting yards. A quantity of rough hewn stone is shown at the side of the lift awaiting transportation.

As Professor Speight says, in many cases where good stone occurs, there is the great disadvantage that it is remote from

railway or other means of carriage, so that the cost of transporting the stone is prohibitive, or nearly so. This is not the case with the Dobson quarry, as it is

connected by rail with the port of Greymouth, and from there stone can be

shipped to its destination quite cheaply. While 'it compares very favourably with any other sandstone obtainable in the

Dominion for ordinary building purposes, the Dobson stone is very suitable for steps, risers and landings, paving sets and curbings, and its durability and weather

resisting qualities make it particularly useful for monuments or pillars to stand the test of time in the open air. RESULTS OF TESTS ON SPECIMENS OF SANDSTONE FROM DOBSON. ABSORPTION TEST. Specimens:— Cubes nominally 2*4" x 2%" x 2%" Actual Dimensions—(l) 2.21" x 2.24" x 2 25" (2) 2,25" x 2.16" x 2 15" Process of Test: —The specimens thoroughly dried and then weighed. Then placed under a vacuum of 28" mercury for 30 minutes, then put into water for 3 days. The specimens weighed again on removal from writer.

WEATHERING TEST. Specimens: —Cubes nominally .1" x 1" x 1" Process of Test: —The specimens thoroughly dried and then weighed (Ist dry weighing). The specimens boiled for 80 minutes in sulphate of soda solution and hung up to dry for 21 hours. Then washed, boiled again in sulphate of soda and hung up to dry. This repeated 7 times, after which the specimens washed and dried thoroughly, then weighed again (2nd dry weighing).

ROBT. J. SCOTT, M.lnst.C.E., Professor in Charge.

Weight of Specimen. Water Absorbed. No. Weight of Specimen. Before After Water Absorbed. After1’er cent, of 1’er cent, of of immersion immersion Grammes original Test immersion (dry) (wet) weight Grammes immersion (wet) Grammes Grammes original weight oi stone i. 446.4 462.2 15,8 3.54 2. 418.0 434.2 16,2 3.87 Average 3.87 3.705

COMPRESSION TEST. Dimensions of Specimen. Maximum Load. No. of Cross-dimensions T ength Tons Tons per Test inches inches total sq.foot i. 2.10 x 2.10 2.20 22.5 701.3 2. 2.25 x 2.25 2.18 23.9 079.8 3. 2.12 x 2.24 2.22 22.3 670.2 ■1. 2.25 x 2.10 2.22 25.2 708.0 Average 700.3

Weight of Specimen. No. 1st dry 2nd dry Loss Loss per cenl weighting weighing Grammes on original Grammes Grammes weight i. 41.40 39.90 1.44 2. 40.57 39.58 0.99 3. 42.G3 41.79 0.84 4. 41.25 39.97 1.28 5. 41.97 40.87 1.10 0. 40.11 38.74 1.35 Total 247.93 240.91 7.02 2.83