Objectif The purpose of the research is: - to establish by measurement whether and to what extent substances contained in the rubber are dispersed into the atmosphere, especially during abrasion of damaged areas of conveyor belts or joint ends, with the result that workers are exposed to hazardous substances in particulate form; - to determine the hazardous vapour or gas emissions occurring when adhesives and rubber solutions are applied, often over large areas, to belt sections which require repair or joining and to the new pieces of belt cover to be fitted and to attempt to derive relationships between the components of the materials used and exposure to hazardous substances at the workplaces; - to measure and assess the hazardous vapours and gases produced in the course of hot and/or cold vulcanisation or of the curing of adhesive splices, with particular reference to the release of nitrosamins.It can be concluded that a calculation of solvent concentrations in respiratory air for exposure determination is on principle possible; ventilation quantities above 240 m{3}/min (test adjustment 0.5 m/s ventilation velocity) show a good agreement between measured and calculated trichloroethylene concentration; low ventilation quantities or velocities respectively lead to significantly higher values in calculations when compared with measurements. Since the directives for the hard coal mining industry prescribe a minimal ventilation velocity of 0.5 m/s for normal operation the requirement of the 'Technical Guideline for Hazardous Substances 402' 'Exposure Determination by Calculation' aiming at conditions like those present in underground hard coal mines can be regarded as fulfilled. Nitrosamines occurring during hot vulcanization were not or only on a small scale analyzed although measurements were performed at sites of highest exposure, ie directly above heating board edges. Operational surface and underground measurements were conducted in hard coal, lignite and potassium mines including associated workshop areas. Exposure peaks of solvent concentrations varied considerably; each evaluation index was below zero.Vulcanisation is the three-dimensional cross-linking of rubber in the presence of sulphur and heat to form a network structure, converting the rubber from a plastic to an elastic state. Since vulcanisation by the action of sulphur and heat is slow, various substances are added to the raw material to accelerate and control the process. In hot vulcanisation the main additives are: - accelerators such as xanthates, dithiocarbamates, thiurams, thiazoles, guanidines, thiourea derivatives, amine derivatives; - activators such as zinc oxide, antimony sulphide, litharge; - fatty acids such as stearic acid; - retarders such as organic acids (benzoic/salicyclic acids, phthalic anhydride, N-nitrosodiphenylamine); - fillers such as carbon blacks, silica gel, kaolin, chalk, talc; - pigments such as organic dyes, lithopones, metallic oxides (Fe, Cr, Cd); - softeners such as mineral oils, ethers and esters; - mastication additives such as chlorinated thiophenols and their zinc salts; - antidegradants such as aromatic amines, phenols, phosphites, waxes; - fire retardants such as chlorinated paraffins, halogenated alkyl phosphates. Furthermore, blowing, preserving, antistatic, mould release and bonding agents are added to obtain particular properties. Although cold vulcanisation is nowadays scarcely used for production, it still has a certain importance in repair work, in which no clear distinction is made between vulcanisation and splicing using adhesives. A common feature of both the cold vulcanisation and adhesive splicing processes, however, is the use of solvents which may have a carcinogenic potential, in particular chlorinated hydrocarbons. In the repair of conveyor belts underground, which primarily consists in making joints to form endless belts and in repairing damaged areas, the first stage is to remove the face and back covers by cutting and/or abrasion and to clean the strength members - the textile or steel carcass. Bonding or adhesive agents, rubber solutions etc are then applied and the belt is reconstructed with new or replacement parts and prepared for revulcanisation. During repair, vulcanisation and splicing activities, the hazardous substances present in the conveyor belts or used in the work may be dispersed into the atmosphere in the form of dusts, vapours and gases and may affect the persons carrying out the work and workplaces downwind. It is hoped that the research findings, together with the specifically mining-related factors of ventilation and exposure to mine ducts, will make it possible to assess the risk arising in such workplaces and downwind. It is also proposed to devise means of reducing emission in the event of non-compliance with the prescribed limits (technically practicable guideline concentrations - TRK - and maximum permissible concentrations - MAK) or of the occurrence of exposure peaks. Programme(s) ECSC-MINEHYG 6C - Sixth research programme (ECSC) "Industrial Hygiene in Mines", 1990-1993 Thème(s) 3 - Dust measurement and determination of dust properties Appel à propositions Data not available Régime de financement Data not available Coordinateur Institut für Gefahrstoff-Forschung der Bergbau-Berufsgenossenschaft Contribution de l’UE Aucune donnée Adresse Waldring 97 44789 Bochum Allemagne Voir sur la carte Coût total Aucune donnée
