The lack of a unified approach to the assessment of professional risks in fuel and energy companies (FEC) in the national regulatory environment and a high degree of subjectivity of the results of hazard identification and risk assessment makes mathematically sound recruitment of an expert group urgent and necessary. The article presents the results of a comprehensive study on hazard identification and risk assessment at 6,105 workplaces in 24 branches of a FEC company based on the application of the expert assessment method and a scientifically sound qualitative and quantitative selection of experts. The priority vectors of factors are determined, global priorities are calculated, the size of the expert group (15 persons) is determined and mathematically substantiated for carrying out hazard identification and risk assessment at workplaces with sufficient reliability of results. For the first time, a set of factors characterizing the FEC companies that influence the determination of professional competence of experts is proposed. The formed expert group presented more precise, objective and consistent results of risk assessment. Standards for free distribution of personal protective equipment (PPE) and wash-off agents to 7,234 company employees for implementation and trial use were developed. A fragment of the results obtained for a driller's workplace is presented. This approach allows a significant increase in objectivity and efficiency of the professional risk management system and provision of the PPE to employees in the concept of a risk-oriented approach helping to prevent industrial injuries and improve the level of occupational safety culture in fuel and energy companies taking into account global practice.
It is experimentally proved that adsorption of Fe(3+) and Sr(2+) cations on Cambrian clay is described by the Langmuir isotherm. The adsorption limit is 0.026 and 0.034 mol/kg, respectively, and the capacity of the clay is 73±5 mEq/kg. The landing sites of cations are 38.0 and 28.6 Å 2 , respectively, and the radii of hydrated cations are 348 and 302 pm. The latter value agrees with the Stokes radius of 309 pm. The Langmuir constants are 731 and 294, respectively, and the distribution coefficients between the solid and liquid phases at rn = 3.0+3.5 are 27±4 and 10±1.8. The ion exchange constant for the reaction ½ Sr 2+ (s) + 1/3 Fe 3+ (aq) ↔ ½ Sr 2+ (aq) + 1/3 Fe 3+ (s) is 0.95. Based on the data obtained, it is feasible to clean the pounds from strontium-90 contamination by washing with a Fe(3+) salt solution. Field tests in the 5th quarter of Vasilievsky Island of St. Petersburg confirmed the conclusion. The initial specific radioactivity of the pound reached up to 1.07 10 -4 Ci/kg. At heap leaching the purification degree of 60% was obtained, in conditions of convective leaching 90%. A formula for calculating the conditions for obtaining a given degree of purification is proposed.
