Spontaneous combustion of coal is one of the major problems in the coal mine. The fire may occur due to exogenous and endogenous causes, by which coal liberated heat to the air or heat absorbed into it. It causes loss...Spontaneous combustion of coal is one of the major problems in the coal mine. The fire may occur due to exogenous and endogenous causes, by which coal liberated heat to the air or heat absorbed into it. It causes loss of production, as well as economical or financial losses and polluted the environment. If, the heat liberated during this process is allowed to accumulate, the rate of reaction increases exponentially and there is a further rise in temperature that generates the flame and produce CO, CO<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub>, O<sub>2</sub> etc. In addition, the heat generated within coal affected by different factors such moisture, ash, volatile matter etc. of coal. This paper deals with the oxidation and spontaneous combustion risk in Barapukuria underground longwall coal mine, Dinajpur, Bangladesh. In this study, the laboratory analyses (proximate analyses) shows the inherent and the total moisture content value is average 2.73% and 5.82% to 12.75%, respectively. It indicates that these moisture contents are moderately liable to self heating. The less ash content value (av.13.2%) shows, it is less liable to spontaneous combustion. In addition to this, the temperature and concentration of some mine gases (CO, N<sub>2</sub>, O<sub>2</sub>) were monitored to calculate the Graham’s ratio. According to Graham’s ratio, the longwall faces have high oxidation risk and medium combustion risk. Therefore, the actual control of spontaneous combustion of coal is important to save coal mine from mine fires and also provides a real opportunity to improve the financial performance of the overall organization.展开更多
Sagardari union is facing groundwater crisis because of contaminations from agriculture and urban sewage,which bring a considerable change in water quality.In view of this,hydro-chemical analyses were undertaken on 35...Sagardari union is facing groundwater crisis because of contaminations from agriculture and urban sewage,which bring a considerable change in water quality.In view of this,hydro-chemical analyses were undertaken on 35 groundwater samples and the following hydro-geochemical parameters,pH,total dissolved solids(TDS),total hardness(TH),electrical conductivity(EC),cations and anions,were analyzed.From the analytical results,it is found that pH value was lower than WHO drinking water standard and the middledownstream portions of the investigation region show higher EC.The piper plot indicates that the groundwater in Sagardari falls in the categories of NaClHCO3 hydro-chemical facies.Higher TH in groundwater was detected,but still in an acceptable range.In addition,salinity and arsenic ratio are higher and moderately higher,respectively.The spatial distribution of Groundwater Quality Index(GWQI)was determined by geo-statistical modelling of Sagardari union.The study provides information and supports the administration which to make better groundwater utilization and quality control in the Sagardari union.展开更多
文摘Spontaneous combustion of coal is one of the major problems in the coal mine. The fire may occur due to exogenous and endogenous causes, by which coal liberated heat to the air or heat absorbed into it. It causes loss of production, as well as economical or financial losses and polluted the environment. If, the heat liberated during this process is allowed to accumulate, the rate of reaction increases exponentially and there is a further rise in temperature that generates the flame and produce CO, CO<sub>2</sub>, CH<sub>4</sub>, N<sub>2</sub>, O<sub>2</sub> etc. In addition, the heat generated within coal affected by different factors such moisture, ash, volatile matter etc. of coal. This paper deals with the oxidation and spontaneous combustion risk in Barapukuria underground longwall coal mine, Dinajpur, Bangladesh. In this study, the laboratory analyses (proximate analyses) shows the inherent and the total moisture content value is average 2.73% and 5.82% to 12.75%, respectively. It indicates that these moisture contents are moderately liable to self heating. The less ash content value (av.13.2%) shows, it is less liable to spontaneous combustion. In addition to this, the temperature and concentration of some mine gases (CO, N<sub>2</sub>, O<sub>2</sub>) were monitored to calculate the Graham’s ratio. According to Graham’s ratio, the longwall faces have high oxidation risk and medium combustion risk. Therefore, the actual control of spontaneous combustion of coal is important to save coal mine from mine fires and also provides a real opportunity to improve the financial performance of the overall organization.
文摘Sagardari union is facing groundwater crisis because of contaminations from agriculture and urban sewage,which bring a considerable change in water quality.In view of this,hydro-chemical analyses were undertaken on 35 groundwater samples and the following hydro-geochemical parameters,pH,total dissolved solids(TDS),total hardness(TH),electrical conductivity(EC),cations and anions,were analyzed.From the analytical results,it is found that pH value was lower than WHO drinking water standard and the middledownstream portions of the investigation region show higher EC.The piper plot indicates that the groundwater in Sagardari falls in the categories of NaClHCO3 hydro-chemical facies.Higher TH in groundwater was detected,but still in an acceptable range.In addition,salinity and arsenic ratio are higher and moderately higher,respectively.The spatial distribution of Groundwater Quality Index(GWQI)was determined by geo-statistical modelling of Sagardari union.The study provides information and supports the administration which to make better groundwater utilization and quality control in the Sagardari union.
