512
2
As to the position of
3. The pumping-station should be placed on the shore, well below the site of the pumping any reservoir that may, at any future date, be constructed. It should be on the
station.
As to the size
beach, near to a spot in the neighbourhood, at which there is about one fathom of water, at low tide, to facilitate landing coals. It will be more economical to take the water down to the coal-supply, than to carry coal up to the pumping-station. Bringing the water down to the pumping-station will not involve any appreciable increase of power, the water would be conveyed, down to the engines, in a pipe of appropriate diameter from which the pumps would draw direct. The water will then rise by gravity to the height of the water-level in the reservoir, or reservoirs, and all that the engines will have to do is to lift the water from the level of the new reservoir to the level of the Taitam Tunnel.
4. I propose that the ultimate pumping-plant should consist of three engines, and power of the engines, each capable of lifting 1,250,000 gallons in 24 hours. Two would do the daily work, with one in reserve. For the present, I recommend that one only be erected. It will be time enough to erect a second or third, when the reservoirs are finished ; and when the actual quantity to be pumped is known by actual observation.
Type of engines.
As to the size and position of the reser-
voir.
As to the diameter of the rising main.
Coal con- sumption.
As
5. It is premature to discuss the details of the pumping-plant. I will now merely say that the engines should be of the most economical type, triple expansion, fully jacketted. The size of the engine, upwards of 100 horse-power, is such as to justify considerable expenditure on arrangements tending to fuel-economy. regards fuel-consumption, I would observe that the actual fuel-consumption of the small engines, now in use, must not be taken as the basis of the calculation of the probable fuel-consumption. The large engine will probably consume, per horse- power per hour, at most one-half, and very probably one-third, the coal that the small engines require.
6. The low-level reservoir or reservoirs, should have a capacity, singly or jointly, of at least about 400 millions of gallons. In the absence of surveys, it is impossible to state where the reservoir should be constructed, or whether there should be several. One reservoir, that to be constructed in the first instance, should be formed, by throwing a dam across the Taitam-tuk stream, as near as possible to sea level, so as to collect, directly, or by catch-water channels, all the waters of the streams, flowing into the head of the Taitam-tuk Estuary. If it be impracticable to make a single reservoir of sufficient capacity, at this site, then others might be built higher up. Perhaps that proposed by Mr. COOPER, at site No. 4, might be one of these. It may be even advantageous to construct those proposed, at sites 1 and 2. They, with Taitam, could be filling, the town being supplied, solely by pumping from the low-level reservoir. For the present, suffice it to say that one reservoir, of the greatest capacity practicable, should be constructed, with its damı as near to sea-level as possible. This should be the first to be constructed.
7. The approximate length of rising-pipe, from the pumping-station to the basin, at the mouth of the Taitam Tunnel is, allowing for the irregularity of the ground, about 9,000 feet, and the lift, including friction, is approximately 400 feet, measured from the bottom of the lowest reservoir. To convey 2,500,000 gallons a day, one pipe of 21" diameter, or two of 15" diameter, would be required. Inasmuch as one engine only is to be provided in the first instance, it will be economical to lay one 15" pipe first; which will amply provide for the water pumped by one engine. The second pipe may be laid later on, when more is known as to the actual yield of the new works. The pump-horse-power of each engine will, therefore, be 105, corresponding to about 124 indicated horse-power.
8. An engine, of the proposed type, should not consume more than 2 lbs. of Welsh or 3 lbs of Japanese coal, per I. H. P. per hour, in actual continuous work. So that the daily consumption, going full speed, will be 1241244 tons of coal per day, costing, say, $10 on wharf, or $40 per day, or at the rate of $0.032 per