![]() The recommended Bureau of Mines research to improve dredge mining safety emphasizes the need for development of an improved personal flotation device (PFD) and the development of means to provide safety information to dredge owners and operators. They include falls into the water slips and falls on the dredge electrical mechanical fire on-shore, hazards and some hazards unique to a small proportion of the dredge mining fleet, such as PCB contamination of the bilges and hydrogen sulfide gas (H2S) release. The hazards are described in Section 2.0. It is representative of a type used in some sand and gravel mining operations, although the one shown was doing lake maintenance in Ohio when it was visited. The dredge in Figure 1-2 is a dragline with a clamshell, mounted on a barge. Thawing of the permafrost usually must precede the dredging by two to three years. The thaw field in the background is part of the preparation for the actual dredging. All of the processing machinery is on board. It is a bucketline dredge used to mine gold in Alaska. The dredge in Figure 1-1 was built 40 years ago. A much smaller dredge of an entirely different type is shown in Figure 1-2. One of the largest dredges observed is shown in Figure 1-1. ![]() The annual material movement ranged from 45,000 tons to more than 11 million tons. The digging methods included suction, cutterhead-suction, bucket wheel, bucket line, and clamshell. The dredges represented a wide range of sizes, digging methods and production. Eighteen of the dredges were “manufactured.” The others were built by local machine shops or by their owners. Ten states were represented in the sample of dredge operations observed. The products extracted by the mining dredges included sand and gravel, gold, phosphate, ilmenite, and coal. Thirty-one dredges were visited to observe design features and safety problems related to dredge operation and maintenance. (In 1974, for example, dredge operations accounted for nearly 25% of the total in the industry and 1974 was not an unusual year in this respect.)Īfter examination of MSHA data and a review of literature on dredge safety, a series of field observation trips was made. A significant percentage of all lost-time injuries in the sand and gravel industry occurs on dredge operations. Nine were killed in fixed machinery accidents five fatalities were related to mobile machinery accidents and four persons were electrocuted. Approximately 63% (or 30) of those who died were drowned. In the years 1973 through 1979, 48 persons died as a result of accidents related to dredge mining operations in the United States. The last four sections provide details about the characteristics of the dredges observed (Section 4.0) summaries of the discussions with dredge manufacturers, consultants and others from whom information was obtained (Section 5.0) the results of the analyses of MSHA data about mining dredge operation fatal and other injury accidents (Section 6.0) and a summary of the literature review (Section 7.0). Immediately following the hazards discussion are the recommended Bureau of Mines research projects which would address the hazards and influence the general improvement of safety in the dredge mining industry (Section 3.0). The report is organized so that the hazards which were observed, or identified in other ways, are discussed first (Section 2.0). The preparation for the field work included reviewing the available literature dealing with safety, examining Mine Safety and Health Administration (MSHA) data on mining dredge accidents and injuries for a period of about five years, and contacting dredging consultants and dredging associations to obtain their general views on safety matters. Visits were made to representative dredge manufacturers to discuss safety from their perspective. Many types of dredges, engaged in extraction of several kinds of minerals, were observed. ![]() The primary method of acquiring safety hazard information was direct observation of active dredge operations in several geographic areas. It included shore-based equipment which supports the dredge or which is in the production sequence immediately following, and regularly interacting with, the actual dredging. The safety hazard consideration involved design and environmental hazards as well as those related to dredge operation and maintenance. The objective of the work reported here was to examine, analyze and evaluate the safety hazards which affect mining dredge workers.
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