THE PANAMA CANAL 



191 



The broken stone for the concrete is 

 quarried and transported from Porto 

 Beilo, about 20 miles east of Colon, and 

 the sand is procured from Nombre de 

 Dios, about 20 miles farther to the east. 

 Both are transported direct to Gatun in 

 barges through the French Canal, which 

 was dredged of rock ledges and accumu- 

 lated deposits for the purpose. Since 

 the canal line was cut through to the 

 French Canal this new channel is also 

 used. The cement is purchased under 

 contract at docks in Jersey City and 

 shipped to Cristobal, thence by barges 

 to Gatun or cars to Pedro Miguel and 

 Miraflores. 



The material taken to Gatun in barges 

 is landed at unloading docks, conven- 

 iently located on the old east diversion, 

 to which a channel from the French 

 Canal was excavated by dredges. The 

 east dock is inclosed, forming the ce- 

 ment storehouse. Its floor dimensions 

 are 106 feet by 490 feet. The roof pro- 

 jects 35 feet beyond the face of the 

 dock, affording some protection against 

 the rains. 



The building is divided into ten bays, 

 in each of which a two-ton traveling 

 crane, worked by electric motors, oper- 

 ate entirely across the building. In the 

 rear of the building 30 cement hoppers 

 are placed in the floors and covered with 

 steel screens. The cement is delivered 

 through these hoppers into cars running 

 on a track below the floor. The cement 

 for this work is in barrels, which are 

 first put into the storehouse and subse- 

 quently moved to the hoppers. 



Grab buckets, operated by cableways, 

 remove the sand and stone from the 

 barges, moored against the west dock, 

 and deliver the materials in stock piles. 

 The towers of the cableways are of 

 steel, 85 feet high and 800 feet apart. 

 They are mounted on cars, which enable 

 movement at right angles to the line of 

 the cable ; one single and two duplex 

 cableways are provided. (See illustra- 

 tion, page 196.) Each of the latter have 

 complete independent cableway systems. 

 The cableways are equipped with five 

 70 cubic feet self-digging grab buckets, 



each having an independent run from 

 the barge to the stock pile. The cable- 

 ways have not the capacity to unload 

 the material required with sufficient 

 rapiditv, and have been augmented by 

 three derricks operating on a dock north 

 of the cement shed, transferring sand 

 and stone to bins. 



THE AERIAL CABLEWAYS 



Two tunnels run north and south 

 through the stock piles, with hoppers in 

 the top through which stone and sand 

 are fed to cars. 



The cars used for transferring the 

 material are of steel with hinged side 

 doors, and bottoms inclined outward at 

 an angle of 52 degrees from the hori- 

 zontal. A steel partition divides each car 

 into compartments, one for rock and ce- 

 ment and one for sand. The car starts 

 at the cement shed, where it receives two 

 barrels of cement, thence runs through 

 one of the tunnels, receiving a full charge 

 of stone and sand in the proper compart- 

 ment, and proceeds to deliver this load 

 in the mixer hopper. 



The concrete mixers are of the cubical 

 type, each having a capacity of 64 cubic 

 feet. There are eight of them, all 

 mounted in one building on the west side 

 of the lock site, arranged so that four 

 dump in one direction and the other four 

 directly opposite, thus permitting the use 

 of two tracks under the mixers. There 

 is, however, but one track above. 



A four-track electric railway, third- 

 rail system, operates the length of the 

 locks and carries the concrete from the 

 mixers to the cableways over the locks, 

 by which it is placed. The equipment 

 for this road consists of 12 electric four- 

 wheel mine-locomotive-type engines and 

 24 flat cars fitted with automatic coup- 

 lers, each designed to carry a two-yard 

 concrete bucket. Two charges of con- 

 crete are taken by each train and carried 

 to the cableways. 



Four duplex cableways span the locks 

 with steel towers 85 feet high and 800 

 feet apart, similar in design to the un- 

 loading cableways. 



The forms used in concrete laying are 



