Engineering Wonders of the World
Volume III

THE COOLGARDIE AQUEDUCT. 383 To facilitate The Aqueduct. level on the up-stream face, but only to within 18 feet of the bed on the lower side ; ■and on them was raised a concrete dam, 760 feet long and 100 feet high above the river bed, tapering in thickness from a maximum of 120 feet to 15 feet at the crest. Nearly 70,000 cubic yards of concrete were consumed in its construction. A draw-off valve tower is situated on the reservoir side of the wall, into which it is built; and a scouring valve tower rises at a point 175 feet below the dam. Provision is made for drawing off water at three different levels through screens, which can be removed for cleaning. The Helena dam, completed in June 1902, impounds a reservoir which., when full, con- tains about 5,000,000,000 gallons of water. Operations connected with the laying of the pipe line were commenced in March 1900. transport of materials the route of the aqueduct followed closely for the main part that of the Coolgardie railway. Where the ground was soft and not saline, the pipes were buried; in rock and hard ground, shallow trenches below and embank- ments above were used ; and across salt lakes or their dry sites the pipes ran on trestles, an insulation of sawdust, kept in place by galvanized corrugated iron, serving as pro- tection against heat and cold. Where possible, the ground was loosened by horse-ploughs to reduce the amount of manual labour required. One-fourth of the total material removed had to be blasted. To promote speed, the trench- ing was begun at several points simultaneously, and in each section kept well ahead of pipe- laying. All the pipes were distributed by means of the railway. Two cars, coupled together, carried eight pipes, three in each of the two bottom tiers and two on top. Eighty-eight to one hundred and four pipes made up a train-load. Twenty-four men, divided into four gangs, could unload the pipes in about an hour. When not engaged in this work the same men busied themselves with the trench digging, matters being so arranged that no time should be wasted. The pipes, laid out in their respective positions beside the trench, were taken in hand by successive gangs. First came the repairers, who made good any * defective areas of pipe coating : Pipelayers ii-i+i i at Work, behind them the men who scraped off a ring of the coating for six inches at each end of every pipe, and chipped the ends of the locking-bars. Next in order were the manhole-cutters ; followed by the pipe- layers, who, with the aid of steel trestles spanning the trench and of winding gear, lowered the pipes into place. Then came the ring-setters, the lead-runners, the hand caulkers, and, last of all, the gang in charge of the mechanical caulking-machine. This device merits a few words to itself. A caulking installation included a portable oil- engine, working a dynamo, from which current was led through a cable to a motor on the machine. The caulker was in two halves, separable to permit them to embrace the main. The motor, attached to the top half, drove the racks operating the steel rollers which forced the lead tightly, but evenly, into the joints at either end of the joint ring. Five semi-revolutions of the rollers usually sufficed to make the joint staunch. Knives were then substituted for the rollers to pare off the lead flush with the rings. As soon as the joint had been “ passed ” by an inspector the trench was partially filled in, completion of this work being reserved for a gang in rear of the machine. About half a mile of pipe could be thus caulked without moving the generating plant to a fresh posi- tion. Good organization and increasing skill enabled the seven gangs to lay, joint, and cover up nearly Ij miles of pipe per day of eight working hours. In 1901, 90 miles of Mechanical Caulkings Machine.