Information contributed by Bill Fall from various early reports.  Great stuff!!

Preparation for Reclamation of Gravel

A span is to be lifted out of the Chagres River Bridge of the Panama railroad, at Gamboa, on Sunday, December 14, to allow dredging equipment to pass up the river to Cruces to recover gravel for use in concrete and in railroad ballast.  The span to be taken out is the second 80-foot plate girder span north of the trussed portion of the bridge, which crosses the riverbed proper.  It will be lifted by wrecking crane and laid on a barge, to be towed aside, as is done with the removable 60-foot span in the trestle at Paraiso.  If the barge used at Paraiso can be towed past Cucaracha slide in time, it will be used at Gamboa also, if not, two of the barges in use north of the slide will be lashed together for the service.  It is estimated that the removal of the span, passage of vessels, and replacement of span, will require about 5 hours.

The vessels to be passed through are the French ladder dredge, No. 1, and a clapet with two barges.  They will proceed to the submerged beds staked off at Cruces before the rise of Gatun Lake, and the material will be handled down to a wharf erected by forces of the Panama railroad on the south bank of the Chagres, about 500 feet north of the bridge.  This wharf is 300 feet long, with its floor at elevation 95 feet above sea level, and is equipped with bins over double tracks for the storage of the gravel and loading into cars.  Unloading from the barges will be done by means of an electric crane formerly used on the sand wharf at Balboa.  The crane is of the fixed cantilever type, with a horizontal trolley extending over the mooring place and over the storage bins.  It is estimated that about 500,000 cubic yards of gravel will be reclaimed by dredging. 

Canal Record Dec 10, 1913  pg.141

Dredging Gravel from the Chagres Arm of Gatun Lake

The ladder dredge, No. 1, which, with the tug DeLesseps and tow barges, was passed through the Chagres River bridge of the Panama railroad at Gamboa, on December 14, for service in the reclamation of gravel form beds submerged by Gatun Lake, has begun operations under a single shift, at a point about half a mile above the former village of Cruces.  The cantilever crane on the unloading wharf at Gamboa is not ready for service on account of lack of connections for the supplying of electrical energy to its motors, and the gravel delivered at the wharf is being unloaded by two 25-ton locomotive cranes, mounted on a track along the outer side of the wharf, and equipped with grab buckets.  The cranes discharge directly into dump cars and not into the storage bins which will be used in connection with unloading by cantilever crane.

                                                            Canal Record  December 31, 1913  pg. 173


Unloading Crane, Formerly at Balboa, Now in Service at Gamboa Gravel Bins

The unloading crane at the Panama railroad gravel handling plant on the bank of the Chagres River at Gamboa was placed in service last week, and is now delivering gravel into the storage bins at a rate of tow barge loads a day.  The crane is one of the three sand unloaders formerly in use at Balboa in the Punta Chame service.  It is operated by electricity generated by a 300-kilowatt motor-generator installed in a building of temporary construction, situated about 100 yards distant from the unloading plant.  The machine was formerly used by the McClintic-Marshall Construction Company in its machine shop at Gatun Locks.  In addition, the power plant is equipped with a 175-horsepower Buckeye tandem engine, formerly used in the pumping plant on the bank of the Chagres River at Gamboa, and prior to that time in the old planning mill at empire; and a boiler, formerly belonging to railroad locomotive No. 203.  the latter is provided with oil-burning apparatus, the oil being supplied from a small tank located on a hill nearby, which , in turn, is supplied direct from the oil company’s main.

Until recently, gravel has been unloaded from barges by a locomotive crane, and the demand to date has about kept pace with the supply, although a small amount has been placed in the storage pile, just south of the bins.  Gravel is dredged and brought to the unloading dock by floating equipment of the Dredging Division.  Dredge No. 1 is engaged in this service, and is now working in a gravel bed a short distance up the river from the site of the old town of Cruces.  When the gravel dredging operations were first begun, it was found that the dredge buckets brought up the material in so dry a condition that the chute frequently became clogged.  In order to remedy this difficulty, two jets of water are made to play under pressure continuously on the material as the buckets dump it into the chute, which serves to wash it down into the barges.  When the barges are full, part of the water is expelled naturally over the sides, and the remainder is siphoned out.  Three barges, one 600 cubic yards capacity, and tow of 500 yards capacity each, together with the tug Delesseps, comprise the remainder of the floating equipment in this service.

With the unloading crane operating steadily, it is expected that from two to three barge loads of sand will be handled daily, except Sunday.  The bins have a capacity of about 2,000 cubic yards, and are similar in construction to the sand bins at Balboa.  It has been found, however, that the valves which control the flow of gravel into cars underneath the hoppers frequently become clogged on account of large stones occurring in the gravel, and to obviate the loss of time in dislodging them, the openings will probably be enlarged.

The force employed on the floating equipment consists of three gold, and 38 silver employees; and at the unloading plant and generator room, three gold, and eight silver employees.  In addition, there is train service attached to the plant, with a regular qualified train crew.  About six dump cars are used about the plant in transferring gravel to the storage pile, etc.  The foreman of the plant is Mr. A.B. Kartz, who occupies married quarters converted from the building formerly occupied by the Panama railroad as a signal station, and known as Tower R.  The most of the silver men at the plant live in boxcars, while the men of the floating equipment eat, and sleep on board.  It is probable gravel dredging operations will continue for a period of about two years, and a large amount will be stored against future requirements.

                                                                   Canal Record March 25, 1914 pg. 292


Work has been commenced by the Division of Municipal Engineering on the bins for the permanent rock-crushing plant at Gamboa.  The equipment to be used is an Allis-Chalmers No. 6 crusher, which will crush the by-product of the gravel plant commonly called No. 1 gravel.  There are about 30,000 cubic yards of gravel stored at Gamboa now, ready for crushing.                 

                                                                       Canal Record  May 3, 1916  pg. 320

Materials for Concrete  (only part pertaining to gravel mining)

Chagres River gravel is being reclaimed at the rate of about 1,500 cubic yards a day.  It is excavated by a ladder dredge, now working a little above the former village of Cruces, and handled to the unloading wharf at Gamboa in clapets.  The tender DeLesseps, formerly towing barges in this service was returned to Culebra Cut in April, as it was not strong enough to handle the barges against the currents which prevail during the rainy season.  The gravel is unloaded by a cantilever crane, formerly at Balboa in the sand service, with a capacity of 250 cubic yards per hour.  The work of this crane is supplemented by a locomotive crane equipped with a clamshell bucket.  Prior to the beginning of the dredging service, gravel was reclaimed by a maximum of two locomotive cranes, equipped with 3/4-cubic yard buckets.  One of these, operated by the Panama railroad, made a high daily record for such equipment by excavating 1,203 cubic yards on February 21, 1913.  Authority has been granted for transfer of another of the sand unloading cranes at Balboa to Gamboa, to furnish additional facilities for handling the gravel.  

                                                        The Canal Record Aug 5, 1914  pg. 496

The French ladder dredge Marmot returned to active service December 8, 1919, and for the remainder of the fiscal year was engaged in the sand and gravel service in the Chagres River, also removing shoal at the Gamboa dock and uncovering the gravel beds.  Al concrete on the Isthmus is manufactured from sand and gravel obtained in this manner. 

                                                           Governor's Report 1920 pg. 66 

  The costs of dredge Marmot are for sand and gravel delivered alongside the gravel dock at Gamboa.  (reference to dredge output table)  mined 134,826 cubic yards of material


The sand and gravel necessary for construction purposes were excavated by the French ladder dredge Marmot in the gravel beds of the Chagres River opposite Juan Mina, about 5 miles above Gamboa.  There were excavated by this dredge and delivered to the Gamboa Handling Plant 104,749 cubic yards of run-of-bank gravel and 15,927 cubic yards of washed sand.  There were also 13,100 cubic yards of mud removed to uncover the gravel beds and 1,050 cubic yards of mud removed in front of the Gamboa gravel dock.  This total of 14,150 cubic yards of mud was dumped in deep water in the Chagres River.  The following amounts of sand and gravel were on hand in stock at Gamboa July 1, 1920:  1,449 cubic yards of sand, 25,038 cubic yards of No. 1 gravel, 4,296 cubic yards of No. 2 gravel, and 51,899 cubic yards of run-of-bank gravel.  There were shipped during the year 39,261 cubic yards of sand, 57,093 cubic yards of run-of-bank gravel, 34,992 cubic yards of No. 2 gravel, making a total of 131,346 cubic yards. 

        Governor's  Report 1920 pg. 73 


The sand and gravel necessary for construction purposes was excavated by pipe-line dredge No. 82 from the gravel beds in the overflow district of the Chagres River above Gamboa.  There were 93,440 cubic yards of sand, 30,582 cubic yards of No. 1 gravel, 101,506 cubic yards of No. 2 gravel, and 43,369 cubic yards of run of bank gravel excavated and delivered to the Gamboa gravel plant for distribution to various divisions.  

                                                          Annual Report 1917 pg. 137-8