JAN. FEB. MAR. APRIL MAY JUNE JULY AUG. SEPT. OCT. NOV. DEC.

591-D-1384

Figure 175. --Contractor's employment at the end of each month, by years.
(Specifications No. DC-5045.)

(b) Wage Rates of Prime Contractor. -- The prime contractor was paid a total of $1,865, 401.24 as the Government's share of changes in labor cost as specified in paragraph 19 of specifications No. DC-5045. The amount represents 85 percent of the difference between the base rates established in paragraph 16 of the specifications and the total wages actually paid to laborers and mechanics for wages paid 365 calendar days after the date of the contract. The following tabulation shows original and latest contractor wage rates and total manhours worked for the major crafts:

1/ Dozer operator

2/Plumbers, boilermakers, electricians, and other miscellaneous crafts.

(c) Employment Record of Completion Contractor (Specifications No. DC-5700). --The employment record of the completion contractor is shown in the following tabulation:

147. General. All personnel working on this project were required to abide by safety regulations set forth by Bureau of Reclamation policy and stipulated in the specifications for contractors. The safety program was administered by the project construction engineer through the project safety officer.

148. Major Contractors' Forces. A full time safety representative was employed by Arch Dam Constructors and under his direction a safety program was organized. Monthly safety meetings were held at the supervisor level. Weekly toolbox safety meetings were held by each foreman and his group of employees.

A hospital was maintained with resident doctors and nurses on duty 24 hours a day until the latter part of June 1963. At this time a first aid station was opened in conjunction with

the contractor's fire station. Nurses were on duty during all the contractor's working hours and a doctor was made available at any time in Vernal, Utah, 45 miles away. An ambulance was available up to the end of Arch Dam Constructors' contract.

Gunther-Shirley-Lane assigned one of their top supervisors the responsibility for safety. This company held safety meetings once a month with their supervisors. Weekly toolbox safety meetings were held with each crew under the individual foreman.

When Arch Dam Constructors were no longer required to maintain a first aid station, Gunther-Shirley-Lane Co. under their contract established a first aid station in the powerhouse in the early part of February 1964, with a nurse on duty 8 hours a day and on call after hours.

The following is a combined accident summary for Arch Dam Constructors and GuntherShirley-Lane Co.:

149. Government Forces. A full time safety officer was employed by the Government for the Flaming Gorge project. Under his direction a round-the-clock safety program was organized for the Government forces for the construction of Flaming Gorge Dam and Powerplant.

The contractor's safety engineer and other top officials met with the Bureau safety engineer and construction engineer on a monthly basis to review conditions and suggestions for safer working conditions for the employees.

The second edition of the Bureau's "Safety Requirements for Construction by Contract" was replaced by the third edition in September 1962, and all contracts awarded after that date were bound by the third edition which gives a much broader coverage than the earlier

one.

The following is an accident summary for the Government forces. The figures include the transmission division Government forces.

CHAPTER XII. Construction. --DAM, POWERPLANT,

AND APPURTENANT STRUCTURES
(Specifications No. DC-5045)

A. Diversion and Care of the River

150. Cofferdams. Specifications No. DC-5045, for constructing Flaming Gorge Dam and Powerplant, required the contractor to submit a plan for diversion and care of the river. In addition to details of the work, the plan was required to show a breakdown of the lump-sum bid for diversion and care of the river into not more than 12 major divisions or items for payment, each item to be paid for as the work included was completed. The contractor made a breakdown of his bid price into nine pay units.

Upon completion of construction and cleanup of the diversion tunnel in early November 1959, construction of the upstream cofferdam was commenced in accordance with the approved plan for diversion. The first step in construction of the upstream cofferdam was placement of a low rockfill across the river in the downstream portion of the cofferdam. Material from the required excavation was used and no difficulty was encountered in closing the river. The flow of approximately 900 second-feet was diverted through the diversion tunnel on November 19, 1959. After diversion, a 6-cubic-yard crawler-mounted dragline was used to excavate the cutoff trench on the upstream side of the rock dike. The river sand and gravel was excavated as deep as possible with the dragline. No attempt was made to dewater the cutoff trench.

Owing to the scarcity of material of impervious nature in the vicinity of the damsite, material for the impervious zone was borrowed near access road station 826+00 and hauled approximately 2 miles to the cofferdam site. This material, a silty sand, was dumped from the trucks into the cutoff trench from the rock dike and no attempt was made to compact it until the fill was above the water table. The only compaction of the impervious zone above the water table was by equipment travel.

Once the impervious zone was above the water, rock from required dam excavation was used to raise the upstream and downstream zones at the same rate at which the impervious zone was raised. Material for the upper portion of the impervious zone was fine sand taken from a borrow area about 500 feet upstream from the left end of the cofferdam. The cofferdam was constructed to elevation 5650 by the end of December 1959, and was raised above the minimum approved elevation of 5685 by the end of February 1960.

The downstream cofferdam was constructed during February 1960 to elevation 5630, or 5 feet above the planned elevation. This cofferdam was constructed in the same manner as the upstream cofferdam, except the fine sand from the borrow near the upstream cofferdam was used for all of the impervious zone.

The cofferdams proved to be very effective and seeped only about 75 gallons per minute during periods of normal riverflow.

151. Dewatering Foundation. The bulk of the dewatering of the area between the cofferdams was done with two 10-inch electric-powered low-head pumps pumping from sumps. Each pump had a rated capacity of 3,700 gallons per minute. Numerous smaller pumps of liquid fuel and pneumatic types were used to collect the water from small sumps. No well point system was used in unwatering the foundation.

Water introduced into the area during cleanup operations and free water in the river sand and gravel as well as inflow, was readily taken care of by one of the large pumps.

The general dewatering procedure was to dig a sump in the area of required excavation some 10 to 12 feet lower than the average level of excavation and install one of the large pumps. When the level of excavation approached the sump bottom elevation, a new sump was excavated and the excavation continued.

After excavation had uncovered most of the area to bedrock, it was found that the surface of the bedrock was lowest at the upstream heel of the dam near the middle of the river channel. A sump was excavated into bedrock, just outside of the required excavation at this point, and used as a primary sump during the remainder of the excavation and during the 1960 concrete placement.