Abstract: The H2S anomalies occurred during the construction and trial production of the Ya Dian coal mine in the northern part of the Binchang mining area in the southern margin of Ordos Basin. During excavation, the maximum is about 140 ppm, and H2S overrun often occurs in fully mechanized working-face of the first mining area. Distribution characteristics of sulfur content in No. 1 and No. 4 coal seams in the study area are mostly ferric sulfate, the pH value of groundwater is alkaline, the geothermal temperature is between 30 and 40 degrees, and the degree of coal metamorphism belongs to non-sticky coal-long flame coal in low rank. No. 1 and No. 4 coal in the western part of the mining area form high sulfur areas around the mining area. After analyzing the factors causing the H2S anomaly, such as the sealing effect of the compact surrounding rock on the roof and floor of the coal seam, the fractured zone runs through the Luohe Formation rock strata, causing the water leaching or water gushing and the low degree of metamorphism, which weakly adsorbs H2S. Measures such as monitoring, ventilation of roadways, blocking by grouting, strengthening drainage and alkaline spraying were taken to effectively prevent and control H2S anomalies and ensure workers’ health and mine safety. Ground temperature of 30 ~ 40°C is the optimum temperature for the reproduction of sulfate reducing bacteria (SRB). The coexistence of sulfate and coal provides material conditions for BSR. Natural gas C2-C8 and unsaturated hydrocarbons in gas residues of No. 1 and No. 4 coal seams provide energy and material basis for H2S production by sulfate reduction. Weak alkaline groundwater with pH 7.7 ~ 8.3 provides living environment for SRB. The water quality belongs to SO4Cl-K+Na type, Salinity of the water is 4.826 ~ 5.277g/l, SO42- content is 2 088.87 ~ 2 292.82 mg/l (greater than 1 500 mg/l), Water is rich in SO42-, so under the condition of hydrocarbon-rich, BSR is easy to occur and hydrogen sulfide is formed. Combined with other conditions, the H2S gas in the mine is determined to be BSR origin.
Abstract: The H2S anomalies occurred during the construction and trial production of the Ya Dian coal mine in the northern part of the Binchang mining area in the southern margin of Ordos Basin. During excavation, the maximum is about 140 ppm, and H2S overrun often occurs in fully mechanized working-face of the first mining area. Distribution characteristics...Show More
