The impacts of alkaline mine drainage on ba, cr, ni, pb and zn concentration in the water resources of the takht coal mine, iran

The release of heavy metals into the environment represents one of the most important environmental effects involved in extracting coal; it needs to be studied more fully. The present research investigatedthe effects of coal-mining in an alkaline environment and alkaline mine drainage in the Takht coal mine regarding the distribution of selected heavy metals (Zn, Pb, Ni, Cr and Ba) on the region's surface andground water . The mine is located 12 Km southeast of Minoodasht, in Golestan province in northern Iran. Samples were collected from groundwater and surface water resources upstream and downstream of themine. The elements' concentrations were measured by the inductively-coupled mass spectrometry (ICPMS) method. The results showed that an alkaline environment was responsible for producing alkaline minedrainage due to the presence of limestone; this caused high pH (8.41) in the area's groundwater resources. Mining activities increased Ba, Cr, Ni, Pb and Zn concentration in the groundwater from 3.39, 0.5, 0.2,0.5, 9.2 ppb to 83.52, 2.2, 0.6, 2.6, 48.3 ppb and from 68.7, 0.5, 1.3, 0.8, 172.6 ppb to 91, 1.2, 4.5, 1.3, 27.6 ppb in surface water, respectively. Due to the basic environment, heavy metal accumulation in the bedsediment for both tunnel effluents and runoffs was higher than during the soluble phase. pH was the main controlling factor in elements' solubility and their distribution in the environment. Increased Ba concentrationin water resources was due to high Ba concentration in the coal, coal tailing and in quarry tailings

The impacts of alkaline mine drainage on Ba, Cr, Ni, Pb and Zn concentration in the water resources of the Takht coal mine, Iran

The release of heavy metals into the environment represents one of the most important environmental effects involved in extracting coal; it needs to be studied more fully. The present research investigatedthe effects of coal-mining in an alkaline environment and alkaline mine drainage in the Takht coal mine regarding the distribution of selected heavy metals (Zn, Pb, Ni, Cr and Ba) on the region's surface andground water . The mine is located 12 Km southeast of Minoodasht, in Golestan province in northern Iran. Samples were collected from groundwater and surface water resources upstream and downstream of themine. The elements' concentrations were measured by the inductively-coupled mass spectrometry (ICPMS) method. The results showed that an alkaline environment was responsible for producing alkaline minedrainage due to the presence of limestone; this caused high pH (8.41) in the area's groundwater resources. Mining activities increased Ba, Cr, Ni, Pb and Zn concentration in the groundwater from 3.39, 0.5, 0.2,0.5, 9.2 ppb to 83.52, 2.2, 0.6, 2.6, 48.3 ppb and from 68.7, 0.5, 1.3, 0.8, 172.6 ppb to 91, 1.2, 4.5, 1.3, 27.6 ppb in surface water, respectively. Due to the basic environment, heavy metal accumulation in the bedsediment for both tunnel effluents and runoffs was higher than during the soluble phase. pH was the main controlling factor in elements' solubility and their distribution in the environment. Increased Ba concentrationin water resources was due to high Ba concentration in the coal, coal tailing and in quarry tailings

Investigation of Acoustic Waves Behavior of an Underground Tunnel in a Multilayer Soil

Understanding the acoustic behavior of buried tunnels is valuable for locating them and monitoring their structure health. This research focuses on the acoustic behavior of buried tunnels in multilayer soil structures. The reflected and transmitted acoustic wave pressure variations are investigated exclusively for a multilayer soil buried tunnel. The tunnel system's 3D finite element model is presented,which contains the tunnel lining, surrounding soil, and the air inside the tunnel and at the ground surface. A free air explosion is used as the acoustic wave source. The reflected and transmitted waves' pressure values are measured to evaluate the effects of mechanical characteristics of soil layers, tunnel buried depths, and lining concrete types on the acoustic wave behavior of the tunnel. In addition, a utility line is introduced to the system in different positions related to the main tunnel to investigate its effect on the main tunnel’s acoustic wave behavior. The results indicate that in a multilayer soil structure, the relative position of the soil layers and the tunnel(whether the main tunnel or the utility line) significantly impacts the acoustic pressure value, particularly the transmitted wave pressure. When changing the tunnel buried depth and the lining concrete type, multiple pressure peaks are observed in reflected acoustic wave pressure–time history exclusive to a tunnel surrounded by a multilayer soil structure. The findings can be used to precisely interpret the recorded signals for structural health monitoring and locating underground structures, especially in a media with multilayer soil structures