floors of the "drys." Thorough drying of the feet and use of foot powders and antiseptic solutions are advised, particularly if signs of infection appear. Daily changes of socks and shoes are also advocated for affected persons.

This article on athlete's foot is just as true today as it was in 1939.

BOILS

Dr. A. L. Murray of the Bureau of Mines reported that the occurrence of boils among employees of mines in a western mining district was influenced by the following factors.

1. Abnormally high temperatures throughout the mine working, together with a nearly saturated atmosphere, which caused profuse sweating and retarded heat elimination.

2. Acid mine water, sulfur gases, and arsenic fumes. The water was high in iron sulfate, and oxidation started on exposure of the water to air.

3. Clothing rubs, slight bruises, infiltration of dirt particles into the skin, and lowered body resistance from general atmospheric conditions were other causes of boils.

The condition can best be prevented by lowering the wet-bulb temperature, by cleanliness, and by removing irritating dusts and gases.

SEWAGE DISPOSAL

Improper or faulty methods of sewage disposal underground help to spread intestinal diseases, notably typhoid fever, dysentery, hookworm, and other parasitic infections. Underground and surface privies should be constructed so as to prevent the spread of disease germs by flies, mice, rats, or water. Tight cans or cans that can be removed and cleaned are provided at many operations; a disinfectant is usually put in the container to kill germs and odor. Flush toilets rarely are installed underground, but satisfactory installations of this type have been made in some metal and nonmetallic mines.

Septic tanks, either steel or concrete, are connected to the toilets by 3- or 4-inch lines; the tanks operate indefinitely without cleaning unless the action of the bacteria is stopped by acid water entering the tank or by some other accident. Action of bacteria in the tank is started or increased at any time by adding a yeast mixture or spoiled meat. Clear water overflow from the tanks flows by gravity to the mine sumps.

CHANGE HOUSES

Included in change houses or change rooms are not only those items necessary for biological or sanitary reasons, such as toilets and lavatories, but also those facilities that add to the comfort and convenience of the worker or are deemed essential by nature of the occupation, such as drinking fountains and locker- and shower-room equipment.37 If, however, these facilities are not kept clean and attractive, employees will be discouraged from taking advantage of them, and the very purpose of the installation will be defeated.

The installation of adequate bathing and toilet facilities for mine employees contributes to both health and efficiency. Laws of

38 39 40

37 Bureau of Mines, Accident Prevention in Nonferrous-Metal Processing Plants. 3. Smelters, Refineries, and Reduction Plants: Handbook, 1955, 380 pp.

38 Harrington, D., and East, J. H., Jr., Change Houses at American Mines: Bureau of Mines Inf. Circ. 7423, 1947, 44 pp.

30 Cash, F. E., and Stott, R. G., Change Houses in the Lake Superior District: Bureau of Mines Inf. Circ. 7489, 1947, 26 pp.

40 Cash, F. E., and Petersen, M. S., Safe Equipment, Guards, and Practices, Lake Superior District Iron-Ore Mines: Bureau of Mines Inf. Circ. 7454, 1948, 98 pp.

many mining States provide for suitable change houses at mines. An example follows from the California mining law.

1. The operator of every mine, except as provided in paragraph 3, shall provide a dressing room or a change house at a place convenient to but not within 100 feet of the mine opening (if the dressing room or change house is made of combustible materials) for the purpose of drying the clothing of the persons employed in and about the mine, and such dressing rooms or change houses shall be provided with adequate means of heating and lighting. Such dressing rooms or change houses shall be available to the men at all times when they are going on or off shift and shall be equipped with shower baths having hot and cold water, at least one shower being provided for each 15 men on a shift working in the mine. Such change houses shall be kept reasonably clean and in sanitary condition.

2. It is recommended that working clothes be either elevated by suitable means, such as chains, to the upper air of the change house, or that separate rooms be used for working and street clothes.

3. Mines employing less than 10 men and having unsuitable water on the property for washing and bathing purposes shall be exempt from the showerbath provision of paragraph 1 of this article; but such mines shall provide their employees with washing and bathing facilities that are reasonably clean and sanitary."

The logical location for change rooms is along the route to and from work and near the entrance to the mine. Some underground mines have separate change rooms for underground and surface employees, and several have a covered travelway or tunnel from the change room to the shaft. Some opencut mines have separate change rooms for the overburden and ore crews.

Change houses or rooms should be lighted adequately by natural or artificial means and heated and ventilated preferably by air-conditioning units. If stoves or radiators are used for heating, the stoves should be guarded and the radiators elevated. The interior arrangement is largely a matter of choice and governed by the individual mine.

Details of desirable features and equipment in change houses can best be given by descriptive photographs.

Figure 15 shows a boot bath in a tunnel or protected travelway connecting the shaft and work-clothes room. The boot bath facilitates cleaning and drying the boots and keeping the room clean.

Figure 16 shows a portion of the shower room in a modern change house. The water-supply lines are enclosed within the walls, reducing the hazard of burns from hot-water lines to a minimum. The shower heads and valve stems extend through the walls. This room is piped for liquid soap, and the dispensers are between the shower valves. The concrete floor has a nonslip surface, and footrails are provided.

Figure 17 shows two types of basins used in change houses: A is the circular or semicircular type operated by hand or foot valve, with the soap dispenser over the basin. B is the conventional lavatory; usually, the circular-type lavatory is used in the work-clothes room, and the conventional type is installed in a section off the street-clothes room. A few mines furnish towels for their employees. At some mines (fig. 18) a room is provided between the showers and the street-clothes room for dispensing towels. The change-house attendant puts the clean towels on the numbered rack and collects the used towels from a laundry bin in the street-clothes room. The employee's work number is on a towel and the rack, and one towel, laundered daily, is used by him until worn out.

41 Department of Industrial Relations, Mine Safety Orders: Industrial Accident Commission, State of California, Order 1764, p. 76.

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Generally, toilet facilities are provided in two rooms adjoining both the street- and work-clothes rooms. In figure 19 the wash basin is in the foreground, the stools and urinals in the rear, the paper-towel dispenser on the partition, and an improvised trash can on the floor.

Separate rooms for street and work clothes are desirable. Steel lockers should be provided for street clothes. The lockers should have solid, sloping tops, and screened doors and bottoms and be elevated to facilitate ventilation and cleaning the floor. Chain hangers should be provided for the work clothes, which should hang from the ceiling on a chain so that air from the ventilating ducts can dry the clothes. The floors should have a finish that will reduce slipping and should be washed after each shift and disinfected frequently.