Soon after the construction of the Panama Canal was commenced the Isthmian Canal Commission bought from the Allis Chalmers Company the first stone crushing plant used in the production of crushed stone for concrete work. This plant consisted of one No. 8 Style “K” and two No. 5 Style “K” Allis-Chalmers “Gates” Crushers, and the necessary auxiliary equipment. The plant was designed by the Allis-Chalmers Company and erected by the Isthmian Canal Commission near Ancon. Its capacity was about 1,000 cubic yards per day of eight hours.
Later on as the work progressed and the Gatun Locks were being constructed the government engineers decided to erect a plant at Porto Bello to produce the crushed stone required for this work. The rock in the Porto Bello quarry was very hard and abrasive, closely resembling that found in the Palisades on the Hudson River, New York. The operations at the quarry being of necessity very large, and the additional fact that the peculiar formation of the rock caused it to blast out in pieces of immense size, made the installation of a large preliminary crusher necessary to obtain maximum operating economies. The engineers of the Isthmian Canal Commission decided upon a No. 21 Allis Chalmers “Gates” Gyratory Crusher for this work as the most modern machine.
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The great and rapid advance made in crushing machinery is shown by the size of the receiving openings of the No. 8 crusher installed at Ancon as compared with the No. 21 installed at Porto Bello. The No. 8 crusher has two receiving openings eighteen inches by sixty-eight inches, whereas the No. 21 has two receiving openings forty-two inches by 114 inches, the former machine weighing approximately fifty tons and the latter about 235 tons. To give some idea of its immense size it should be noted that it will take pieces weighing four to five tons, breaking them down to about seven inches in one operation. This large crusher is capable of easily crushing 5,000 cubic yards of rock in eight hours, although it was never extended to its fullest capacity as only 3,500 cubic yards were used at the Gatun lock daily. The enormous size and weights of the individual pieces that go to make up this machine made the transportation and installation (the plant being located several hundred feet above water level) a difficult one, and much credit is due the management and engineers of the Isthmian Canal Commission in successfully mastering these problems.
The rock in the quarry was loaded with large steam shovels into six to eight-ton side dump cars, and trains of ten cars were brought by locomotive to the crusher and discharged into the feed hopper. After being crushed in this preliminary breaker to about seven inches the material dropped into a sixty-inch Allis-Chalmers pan conveyor and elevated to additional crushers which further reduced it to about three and one-half inches. The material used in the concrete work at Gatun locks being “crusher run,” no sizing screens were necessary at the crushing plant. Its location being on a hill-side, all the crushed material flowed by gravity to a final conveyor located at the foot of the hill which carried it to the storage bins. These bins were located on Porto Bello harbor, and the material was loaded directly from these bins into barges having a carrying capacity of about 700 cubic yards. The barges were towed to Gatun, a distance of about thirty-five miles, and there unloaded with clam shell buckets.
**Bennett, Ira E. “History of the Panama Canal: Its Construction and Builders.” Google . Google Books.
Austin M. Frederick 