worthless in the event of fire. A fire extinguisher that has been used should be refilled immediately; it should never be restored to its normal storage space without first being refilled. Care should be taken to replace the contents of a fire extinguisher as often as the manufacturer recommends so that the extinguisher is always in condition to meet emergencies. Some mining companies have established the practice of having tags attached to each chemical fire extinguisher and require the inspector to write his name and the date at each inspection and the dates of refilling. Thus, each extinguisher carries its own record. If municipal fire-department facilities are available, fire-hydrant couplings should be standard and interchangeable with those of municipal fire departments, or suitable adapters should be provided. In certain instances mining companies have called municipal fire departments to assist in extinguishing fires only to find that company fireplug hose connections were not standard and adapters were not available; the municipal fire departments were therefore unable to render effective assistance. A company should inquire about the size of municipal fire-department's hose connections and install the same size or have adapters available before an emergency arises. Smoking in or about surface buildings or structures should be restricted to places where it will not create a fire or explosion hazard. Smokers who are careless in disposing of lighted matches, cigarettes, cigars, or pipe contents are probably the greatest single source of ignition of surface fires. Because smoking is universal its control is a formidable task. Prohibition of smoking is difficult to enforce unless rigid supervision is maintained. Where a fire or explosion hazard exists, a practice that is sometimes successful is to designate and maintain certain restricted zones where smoking is permitted. Some fires have been attributed to spontaneous combustion of oily waste, cloth, or wiping rags; tight metal receptacles should be provided for the disposal of oil-soaked material. Oil spillage should be cleaned up immediately; when this cannot be done the spilled oil should be covered with sand or other nonflammable absorbent to prevent enlargement of the spillage area. SURFACE-UNDERGROUND PROTECTION MACHINERY AND HAND TOOLS MACHINERY In devising protection from moving machines and machine parts the goal should be to make the protection as effective as possible. This is difficult to achieve because some persons are prone to be where they have no concern, and their curiosity with regard to moving parts may lead to disaster. All possible contingencies should be considered, including acts of thoughtlessness and foolhardiness, in applying guards for machine and tool protection. Machinery and belt drives exposed to possible personal contact should be guarded adequately: 1. Gears, sprockets, friction devices, collars, flat or grooved pulleys, and couplings with protruding bolts or nuts should be guarded completely. 2. Shafting and projecting shaft ends within 6 feet of a floor or platform level should be guarded thoroughly. 3. Vertical or inclined belt, chain, or rope drives should be guarded adequately to a height of at least 7 feet (measured vertically) above a floor or platform. 4. Horizontal belt, chain, or rope drives within 7 feet (measured vertically) above a floor or platform should be well-guarded. 5. Flywheels should be guarded. If a flywheel extends to a height of 6 feet or more above a floor level, it should be guarded to a height of at least 6 feet. If a flywheel extends to a height of less than 6 feet above a floor, it should be guarded for its entire height. 6. Circular and band saws (fig. 16) and planers should be guarded. Guards for these machines are usually standard factory equipment. 7. Locomotive repair pits should be guarded properly, and the guards should be kept in place when a pit is not in use. These guards are generally steel plates, steel grille, or wooden planks. 8. When guards or safety devices are removed from machines, drives, or other parts to permit repair, adjustment, cleaning, or lubrication they should be replaced promptly. Guards for machines and machine parts should be substantially constructed; usually they are made of solid metal, perforated or expanded metal, screening, and sometimes wood. One of the most-common causes of accidents around machinery is the failure to replace a guard or safety device that has been removed to permit repair of the machinery or for some other purpose; constant supervision is necessary to prevent this type of negligence. Power-driven grinding wheels should be equipped with: 1. Safety washers or protective flanges on the vertical faces. 2. Substantial retaining hoods, the throat openings of which do not expose more than a 90° sector of grinding wheel; not more than a 60° exposure is preferable. 3. Where grinding operations are frequent or constant, a dust-collecting system should be installed or a permissible respirator should be worn by the operator. 4. All grinding wheels should be guarded with eyeshields. The American Standards Association has formulated standards for guarding machinery; copies of the standards may be obtained from the Association at a nominal cost. Several of the States also have formulated safety standards for mechanical power transmission and guarding machinery; in these States such equipment must be guarded in accordance with the State standards, which may be supplemented by other requirements if necessary. Machinery in motion should not be repaired or adjusted. Oiling machinery in motion should not be permitted unless it can be done without danger to the oiler. Many employees have suffered serious and fatal injuries while working around moving machinery, particularly from getting their clothing caught in moving parts. Adequate clearance should be maintained between machines, and all walkways or aisles between machines should be kept clean and free of obstructions. Congested conditions between machines or poor housekeeping have caused many persons to stumble and fall against machinery. Passageway around machines should be illuminated adequately. All persons engaged in welding operations should be provided with suitable shields to protect their eyes. The intense light rays from welding are harmful to the naked eye; without protection irreparable damage can be done to the optic nerve. A welder should also wear protective goggles to prevent flying particles of molten metal from injurying the eyes. Stationary welding locations should be well ventilated to dissipate fumes and should be guarded to protect other workmen against eye injuries and burns from flying particles of hot metal. Fire-fighting equipment should be available immediately where welding is done. HAND TOOLS Unsafe hand tools are common causes of injuries that can be prevented. Good tools lessen labor and increase capacity for production. Dull picks, axes, and hatchets; saws with loose handles; mushroomheaded sledges, hammers, and chisels; and dull, short, crooked bars are dangerous tools. Files should have handles because numerous puncture wounds are caused by unprotected file tangs. Tools should be kept in good condition, safe for use and used safely; they should not be left where men may stumble over them. Many accidents are caused by the use of improper tools-use of a wrench for a hammer, a pick for a bar, an ax for a saw, etc. Miners should be provided with adequate tools in working places, and officials should make frequent inspections to see that the tools are maintained in good condition. Many timbermen and miners have had fingers amputated or otherwise seriously injured by using an ax while trimming props, cap pieces, and wedges. If axes are used as one-handed tools underground, the over-all length of the handle including the part that fits into the "eye" of the ax should not exceed 18 inches. Some companies have eliminated many injuries by furnishing prepared cap pieces and wedges and prohibiting the use of axes by the miners. A good saw should be included in each miner's set of tools, particularly where axes have been prohibited. Percussion tools such as chisels, punches, cutters, hammers, and sledges should be hard enough to withstand blows without mushrooming excessively and tough instead of brittle to eliminate chipping or checking. Percussion tools are safer when a little soft than when too hard. A soft tool may require frequent dressing, but this is preferable to having a chip fly from a brittle tool when struck with a hammer or sledge. The penetrating power of a flying chip from a tool is astonishing. Chips from hand tools have caused the loss of eyes and even fatal injuries when arteries have been severed. Soft-metal hand tools should be dressed as soon as they begin to check. A tool can withstand more pounding with less danger of chipping when a slight curvature is ground on the edge of the head of the tool in dressing; tests indicate that a radius of curvature of 316 inch is most satisfactory on hand tools. Wooden handles for hand tools should be well-secured to the tools by wedging to prevent the tools from leaving the handles when struck. Split wooden handles should not be permitted because many injuries have been caused by them. PLANT HOUSEKEEPING Good plant housekeeping is one of the most-important factors in accident prevention. It has been defined as cleanliness and orderliness. At some mines little attention is given to the orderliness and appearance of the surface plant and underground works. All sorts of scrap iron, old cars, and timbers are permitted to be scattered around the plant yard; underground haulage roads often are dirty; and scrap material or other refuse is permitted along the clearance side of haulageways. Such carelessness not only presents an unsightly appearance but is hazardous. Good housekeeping includes the removal of possible sources of injury such as protruding nails, broken glass, and all kinds of stumbling hazards. The desire for good housekeeping must originate in the directing head of the mine organization. When the management insists upon neatness and orderliness the plant likely will be neat and orderly, particularly if the officials set the proper example. Figure 17 is an exterior view of the tipple and cleaning plant at a bituminous-coal mine; the yard indicates good housekeeping. Figure 18 is a photograph of another attractive mine yard showing the wash house and the lamp house. Some companies provide bins for the storage of scrap iron and timbers; these are neatly stacked according to kind or size. Underground roadways are kept clean, material is not stored in shelter holes or on the clearance side of haulage roads, and the officials insist that the workmen practice good housekeeping in their working places. Experience has shown that good housekeeping pays definite returns; it is attended by fewer accidents, decreased accident cost, increased production, reduced loss or waste of materials, longer life of mechanical equipment, and better morale among the employees. Some phases of good housekeeping underground are shown in figures 19, 20, 21, and 22. FALLS OF PERSONS Throughout this and the preceding sections of this series of miners' circulars pertaining to the prevention of accidents at bituminous-coal mines recommendations have been made to prevent falls of persons. Many persons are injured, some fatally, by stumbling, tripping, loss of balance, slipping, etc. Accidents from such causes may be minimized by instituting and maintaining certain physical or structural safeguards, together with good housekeeping practice. To recapitulate, openings in floors of structures should be covered or guarded to prevent persons from falling. Stairways and runways should be guarded and provided with suitable dependable handrails. Persons working on head frames, repairing shaft linings, and doing similar work should wear safety belts to protect against loss of footing. Poor housekeeping is an important cause of accidents from falls. Surface supply yards should be kept clean, particularly where people ordinarily walk. Shops and supply houses should have clean, wellmaintained aisle space to minimize slipping and stumbling of persons. All machinery should be well-guarded to prevent injury to those who lose their footing. Oil spillage in oil-storage houses, if not cleaned immediately, presents a slipping hazard. Poorly maintained or obstructed clearance space along roadways in bituminous-coal mines increases the stumbling and falling hazards where foot travel is permitted. Wet roadways, particularly with a fire-clay bottom, are dangerous because they are slippery and conducive to falls; they should be drained and coated with nonslipping material such as dry sand or small crushed stone. Where men must travel in manways in which falls of roof have accumulated so they must crawl over them and can walk only with effort, injuries from slipping, tripping, and stumbling will be more numerous than where clean, |