Stones

STONES, see Concretions. STONE EXTRACTION AND PROCESSING. Natural stones used for various purposes in industry and construction are quarried in so-called quarries, which are most often open-air (work is performed under the open sky), and significantly less often - underground. Production processes. The method of stone breaking - the main production process in quarries - depends on the properties of the rock being extracted and its purpose. Stones of softer rocks are usually broken manually with the help of very primitive tools: iron crowbars, chisels, picks, hammers of various sizes and weights, wedges, etc. At present, however, mechanization of work has become widespread in quarries, as in mines, as a result of the use of cutting machines. When breaking stones of hard rocks, explosives are often used, placed in pre-drilled holes - drill holes. Manual drilling - a very heavy and strenuous job - is increasingly giving way to machine drilling using compressed air or (less often) electrical energy. Following the breaking, there are further stages of the production process: lifting the stones, transporting them, stacking them in piles or heaps; these operations, although usually performed with the help of appropriate mechanical devices, nevertheless require very significant participation of human muscular strength. Processing of stones (with the exception of initial rough dressing) is done outside the quarry either in special workshops, or in specially, ad hoc arranged temporary premises, or in the open air (often under a canopy). Various processes of stone processing, such as: rough dressing, sawing, turning, grinding, polishing, etc., are performed partly by machine and partly by hand. The manual method of stone processing is especially characteristic of the work of stone carvers, as well as grinders and polishers, mainly of soft rocks (e.g., marble, lithographic stone).- Rough dressing has the purpose of removing irregularities and giving the stone a proper appearance. The stone carver performs his work with chisels and gouges, hammers of special design and various calibers: "tesoviks" with which they strike with full force on the protruding parts of the stone (initial rough dressing), and "kiurs" (semi-fine and fine dressing), picks (dressing of soft stones) and "scarps" - gouges with a flat blade (hollowing out recesses and grooves).- To give the stone a completely clean and smooth appearance, it is subjected to grinding and polishing either on machines or by hand. Manual grinding of marble, granite, alabaster, selenite, porphyry and others is usually done with the help of a piece of stone (sandstone, granite) or metal (iron bar) with some water-lubricated abrasive material: quartz sand, emery, pumice, etc. For polishing, the ground surface is rubbed with cloth edges, rolled in a certain way ("kukla"), pieces of felt with emery, tin ash (product of burning an alloy of tin and lead) and other polishing materials. Final polishing is done dry with dry rags with talc, chalk, etc. STONE EXTRACTION AND PROCESSING Hazards and dangers. The main professional hazard in stone extraction and processing is mineral dust, which is formed in larger or smaller quantities during all production operations without exception. Work in quarries, stone carvers and stone grinders proceeds especially under conditions of abundant dust formation. The wet method of processing, used in some operations, somewhat moderates the dustiness of the air, but the number of such operations is relatively small. Breaking stone with explosives and the use of pneumatic tools, while fully justified from a technical and partly also general hygienic point of view (significant reduction in the share of heavy muscular labor in the production process), play a negative role in terms of dust formation, as they contribute to the formation and release of excessively large amounts of dust into the air. In terms of chemical composition and morphological properties, the most unfavorable types of stone dust are those that contain a high percentage of silica-rich quartz particles. These primarily include sandstone dust, especially that of hard sandstones - silica, quartzite (pure SiO₂), sandstones for millstones, for the inner lining of metallurgical furnaces (e.g., English sandstone "ganister", containing 95% SiO₂ and having diamond-like hardness). Next comes granite dust, in which quartz is mixed with a large amount of mica and feldspar. Marble dust, limestone dust, etc. are less harmful.- Among other professional hazards, the most significant are: heavy muscular labor, often performed in bent and other forced unnatural body positions; dampness and moisture - constant companions of work both in quarries and (although to a lesser extent) in a number of stone processing operations; effects of bad weather. Further - body vibration when working with pneumatic tools (especially when drilling in quarries), excessive strain of the wrist and fingers of the left hand in stone carvers (fixing the chisel), possibility of inhaling gases during blasting operations, contact with lead when polishing with "tin ash", possibility of parasitic infections, in particular ankylostomiasis (see Ankylostoma).- The causes of accidents, the danger of which in this production is extremely great, are collapses and cave-ins, falling objects and people, explosions, fragments getting into the eyes, etc. Professional diseases. In accordance with the main production hazard - inhalation of stone dust - the first place here is occupied by diseases of the respiratory organs: catarrhs of the upper respiratory tract, bronchitis, pneumonia, emphysema and, having especially important significance, a typical form of pneumoconiosis for this group of workers - chalicosis (resp. silicosis), often complicated by tuberculosis. Numerous statistical data testify to the high level of respiratory organ morbidity among workers in stone extraction and processing. Sommerfeld in 1892 found among 2,015 Berlin stone carvers 18% suffering from general diseases of the respiratory tract, and 19% with tuberculosis. According to Calwer's data, among 1,209 German stone carvers who died during 1886-98, 86.3% died from diseases of the respiratory organs, including 58% from tuberculosis. Similar data are found in official statistical studies of professional mortality and morbidity in various countries and sick funds (England, Switzerland, Holland, Bavaria, Leipzig, Württemberg, etc.). In Holland, for example, the mortality from tuberculosis among stone carvers and marble workers in 1908-1911 was four times higher than the average for all professions (Prinzing); In Bavaria in 1908 the mortality coefficient of stone carvers from tuberculosis was 26.85 per 1,000 living with a coefficient of 3.07 for all male professions (Kolsch). According to English statistics for 1910-12, workers in the stone quarrying and stone processing industry gave the following standard mortality rates from respiratory diseases and tuberculosis of the lungs (per 1,000). Worker groups Tbc of the lungs Other | diseases of the respiratory organs | Quarrying and processing of sandstone 5.85 1.79 1.82 2.0 4.38 Quarrying and processing of granite » » » limestone 0.9 1.55 All male population of England 1.68 It is necessary to emphasize that in the light of the modern level of our knowledge in the field of lung dust diseases, which indicates the extreme difficulty of their differential diagnosis, these data of old researchers and official mass statistics - at least in relation to the indicators for tuberculosis - are not entirely reliable. It should be assumed that in very many cases where tuberculosis is mentioned, advanced forms of pneumoconiosis complicated by the tuberculous process took place. Much more reliable in terms of the accuracy of diagnosis of individual forms of respiratory diseases are the later data. Kelsch and Arnstein in 1915 among 100 sandstone stone carvers in the Lower Main region objectively established bronchitis in 66 people, and tuberculosis in three. Examination of 919 workers in sandstone quarries in the state of Ohio in North America (1926) revealed 54.9% with silicosis in various forms, and 2% with silicosis simultaneously with tuberculosis. Among other diseases should be noted: diseases of the cardiovascular system, partly in connection with chronic lung diseases, partly on the basis of heavy physical exertions (alcoholism, which is also widespread among quarry workers and stone carvers, plays a significant role here), then rheumatism, skin diseases (under the influence of dust and dirt), hernias. Specific to stone carvers are the characteristic dense calluses on the dorsal side of the main phalanx of the little finger of the left hand, formed by the method of fixing the chisel between the thumb and little finger on one side and the three middle fingers on the other. Cases of lead poisoning are sometimes observed in marble workers when using lead-containing tin ash for polishing (Sternberg).- Traumatic injuries, especially among quarry workers, are very frequent.

Per 1,000 'full-time' stone quarries in Germany in 1918-20 there were 66.94 accidents, including 10.82 serious ones. In 1920, the accident rates for stone quarries were as follows: total accidents 9.93, including temporary disability 5.22, permanent disability 3.35, with fatal outcomes 1.36 (the corresponding average rates were 6.31; 3.52; 2.06; 0.73). Eye injuries are particularly frequent. Health improvement measures. Mechanization of processes where possible according to production conditions; maximum dust removal by means of ventilation devices, humidification of the extracted and processed material, regular removal of dust masses, regular cleaning of work premises by wet methods, etc.; rational work clothing; during the dustiest moments of work - respirators and masks, protective glasses with unbreakable glass; protection of workers from the effects of adverse atmospheric conditions by means of canopies, etc.; provision of rooms for rest and food intake and a number of other general sanitary measures. Safety measures require special attention. In many countries, the protection of workers in the extraction and processing of stone is regulated by special legislation. Labor legislation in the USSR provides for safety measures in stone quarries (Sections VIII and IX of the 'Safety Rules for Mining Operations' of 25/XI 1924). Persons under 18 years of age are not admitted to the dustiest and most strenuous work.