Distance Control and Positive Security for Intrinsic Equipment Working in Explosive Potential Atmospheres

In this paper, intrinsic safety and positive security distance control for an up/down elevator which extracts the materials from an underground coal mine is approached. For a better understanding of intrinsic safety and positive security, the first part of the paper describes the potential risk the workers are facing while working in dangerous environments like coal mining with “grisou” atmospheres and what the conditions of an unfortunate event to take place are. We presented the diagram and working principle for intrinsic safety equipment used in potential explosive areas based on which we modeled and simulated the intrinsic and positive security distance control in order to get a software solution for it. We created an algorithm and simulated the process in Matlab Simulink. The simulation results done in Matlab Simulink were then entered into a Moeller PLC using a ladder-type programming language. For protection against explosive atmospheres, the PLC is inserted into a metal housing with intrinsic protection and Positive Security.

Increasing the Safety of People Activity in Aggressive Potential Locations, Analyzed through the Probability Theory, Modeling/Simulation and Application in Underground Coal Mining

This paper deals with the increasing safety of working in aggressive potential locations, having SCADA system and WSN sensors, using a “probabilistic strategy” in comparison with a “deterministic” one, modeling/simulation and application in underground coal mining. In general, three conditions can be considered: 1) an unfriendly environment that facilitates the risk of accidents, 2) aggressive equipments that can compete to cause accidents and 3) the work security breaches that can cause accidents. These conditions define the triangle of accidents and are customized for an underground coal mining where the methane gas is released with the exploitation of the massive coal. In this case, the first two conditions create an explosive potential atmosphere. To allow people to work in a safe location it needs: first, a continuing monitoring through SCADA system of the explosive potential atmosphere and second, the use of antiexplosive equipment. This method, named “deterministic strategy”, increases the safety of working, but the explosions have not been completely eliminated. In order to increase the safety of working, the paper continues with the presentation of a new method based on hazard laws, named “probabilistic strategy”. This strategy was validated through modeling/simulation using CupCarbon software platform, and application of WSN networks implemented on Arduino equipments. At the end of the paper the interesting conclusions are emphases which are applicable to both strategies.