The copper era and Morenci leader., 1913-01-31

of it is decomposed and clayey, and , there are also rotten shales and in ; terbedded Ignite, the whole intercept } ed by cross slips and faults, conse
 quently, in many places the sides will not stand up at any ordinary angle
 but keep sliding in, ever breaking away further and further back from
 the cut till in one case discovered dur
 ing my visit a new break was found
 in the jungle three quarters of a mile
 back from the cut; in some cases they move slowly; in others they come
 quickly with little warning and bury
 muck trains and steam shovels that
 cannot be gotten out of the way in
 time.
 There are about 45 steam shovels
 at work in this cut at present, load ing 1,500 yards a day each. The
 muck is hauled away in trains of twen-
 ty cars of 20 yards capacity each, or
 about TO trains per day; it is indeed
 a busy sight. Hundreds of churn
 drilling the holes far in advance of
 the shovels, and the blasting is done
 at night. The steam shovels are
 operated with coal, but the machine
 drills are run with compressed air
 carried along the sides of the cut in
 eight inch pipes. There are three
 power stations compressing air for
 this system, one at each end and one
 at the middle. The dirt thus exca-
 vated is run out and used for dams, or filling swamps, or dumped where convenient
 Practically all the rest of the ex- cavation is done with dredges, the largest of which was built in Scot l land, and is working in the Pacific end of the Canal; this has capacity of 700 yards per hour. The principal features of interest in the Canal are perhaps the locks There are three sets of double locks near each end; these are most spectacular creations of concrete and in their internal work ing arrangements are most interest ing.
 Entering the Canal from the At lantic, vessels will steam at sea level through a channel miles long to Gatun, where the first locks are situa- ted; here they will be forced to come to a dead stop and tie up at an ap- proach pier 1000 feet long; they will then be taken in charge by 4 electric locomotives, ? to pull in front and 2I to restrain behind the front gates will be opened and they will be lowed in and the gates closed behind them; the locks are 1000 feet long by 11O feet wide, so will accomodate the largest vessels now in use. The water will be let in through a tunnel in the side wall and will rise through holes in the bottom of the lock, raising yes sells 2S.3 feet in the first lift They will then be lowed into the second lock and be raised another step of 2S.3 feet; and finally into the third lock and be raised another 2S.3 feet, i making S5 feet total lift; they then come out at the level of the Gatun Lake. These locks required over two million yards of concrete; the huge gates and mechanism for operating them, as well as the valves for let | ting in and out the water, are extreme ly interesting; also the precautions | provided for the prevention of acci- | should they occur.
 Should, for instance, vessel fail | to come to a stop at the approach | pier, a huge chain attached to a hy- draulic cylinder and stretched across the entrance to the lock will be en- countered; this will be capable of retarding a 10000 ton vessel going at the rate of 4 miles per hour in 70 feet. Should the chain fail, the front gates of the lock are made in two sets; the first set may be carried away or disabled, but there is still the second set to fall back on; or, if the accident be so terrible that all the gates are carried away and the con- tents of the lake begin pouring through the locks unrestrained and to destroy them, then huge steel emergency gate is provid ed to be swung across and gradually close the gap, after which a pontoon gate will be floated into place and seal the entrance; noth- ing appears to have been left un- thought of.
 The Gatun Lake has been formed {; by the damming of the Chagres River [ at Gatun, near it's mouth. This is a { great piece of work; the dam is mile and half long and 2,S0O feet thick at { the bottom, and raises the water S5 $ feet. It consists of two walls made of { rock dumped by the muck trains from {