ARTESIAN WELLS THROUGH ROCK AND CLAY.

Hawke's Bay Herald, Volume 12, Issue 914, 4 February 1868, Page 2

ARTESIAN WELLS THROUGH ROCK AND CLAY.

Napier, Jan. 29, 1868. Sir,—The matter contained in the enclosed copy of a letter from Mr. Charles Floekton, of the firm of Messrs. Flockton and Co., Civil and Mechanical Engineers, giving particulars in detail, accompanied by diagrams, of the sinking of an artesian well on their premises through rock and clay strata, may possibly interest some of your readers —more especially those resident in Napier—l therefore forward it for publication (with your permission), and would add that should the diagrams be found too small, I shall, be happy to furnish you with larger copies for the inspection of those interested.—Yours, &c, W. R. Carver. [Copy.] . Timaru, Jan. 11, 1868. Sir,— ###### The entire depth of our well is 72 feet, and the diagram below will best show the stratification. ****** I shall best explain matters by giving you a description of our proceedings from the commencement. The men who were employed by me were the only two I could find who had ever sunk a colliery shaft, and bored for coals, and I selected them as they had already tried several wells for various owners of property, none of whom required either the quantity or quality of water which we do, and upon meeting with a moderate supply in the shaley clay and porous rock, they ceased their operations. First, we sunk through, the clay a well 4 feet in diameter to the face of the rock, when we commenced blasting, which at once rendered it necessary to secure the shaley clay by a strong tubing of wood, which was not fixed without our first having some tons of soil falling from the face of the shale. We blasted for 20 feet, when I deemed the rock sufficiently solid to admit of boring (the previous porous rock being intersected with veins of clay at all angles, sufficient to turn a drill out of its true course). Boring began with a 3-inch chisel jumpier, of .the ordinaiy form ; but on getting this down some 4s feet, I found it did not work well, and therefore reduced the bore to 2 inches, keeping to this size all through. At 21 feet bore struck clay, through 3 feet of clay into shingle, when the water at once rushed up the bore hole into the well, bringing up some 20 or 30lbs. weight of black sand washings, containing iron, and also the merest trace of gold. We then plugged the hole with the drill in it, washed and cleansed the rock, removed the tubing, and bricked up our well to the mouth, after which we removed the drill, inserted I^-inch pipe about 6 feet in the bore hole, and then secured it with wedging watertight, and screwed on other lengths, when the water rose 17 feet from the bottom of the well, or 30 feet from the surface, and beyond this, by every known (and some hitherto unknown to me) plan of artesian well sinkers, we could not get it to rise —the level of it being equivalent to high water of the sea, showing clearly that the water has vent into the sea under the rocks, but sufficiently contracted to draw it back to sea level. We then made an inverted rose head for our pipe, left the fixed length projecting upwards about 5 feet from the bottom of the well, screwed on the rose; the water rushed into the well with a full I^-inch stream, and rose to the level already named; since which time we have supplied every one with as much water as they liked to draw, including some 1500 gallons to the ship Red Rover, drawn in one day. Water from the surface of the well at 8 a.m., 30 feet; at 5 p.m., 29 feet 3 inches ; at 5.15 p.m., 30 feet—showing the supply to be one constant stream. The water is pure, bright, and tasteless, not excessively hard (very fair for washing purposes); but I should judge it to contain, a trace of sodium. There is never the slightest trace of any brackishness. The time occupied was about 8 weeks, and the total cost was very low, not exceeding £70, including bricks and bricking. The jumping tool was made on our premises, all in one length, and was welded together in pieces of 8 feet, as most convenient. The cutting end is like this : — *#** * • * And, in boring, a common scraper was used as far as possible to clean the hole; after which it was kept pretty clean by means of pouring water in, and so causing the debris to rush out as liquid mud, by the "jump," "jump," of the tool. Such jumping being done by the men grasping the rod, and lifting it perpendicularly, and then allowing it to fall by its own weight. When engaged in the sinking, I designed a small and effective machine for lifting the tool, in case, by reason, of itsovrn weight (from excessive depth) we should have been unable to lift it; but, fortunately, did not require it.—l am, &c, ■ Charles Flockton, Civil Engineer. W. E. Carver, Esq., Napier. [The diagrams referred to will be left at this office for inspection.]