Identified the hydrochemical and the sulfur cycle process in subsidence area of Pingyu mining area using multi-isotopes combined with hydrochemistry methods

Groundwater serves as an important water source for residents in and around mining areas.To achieve scientific planning and efficient utilization of water resources in mining areas,it is essential to figure out the chemical formation process and the ground water sulfur cycle that transpire after the coal mining activities.Based on studies of hydrochemistry and D,^(18)O-H_(2)O,^(34)S-SO_(4)isotopes,this study applied principal component analysis,ion ratio and other methods in its attempts to reveal the hydrogeochemical action and sulfur cycle in the subsidence area of Pingyu mining area.The study discovered that,in the studied area,precipitation provides the major supply of groundwater and the main water chemistry effects are dominated by oxidation dissolution of sulfide minerals as well as the dissolution of carbonate and silicate rocks.The sulfate in groundwater primarily originates from oxidation and dissolution of sulfide minerals in coal-bearing strata and human activities.The mixed sulfate formed by the oxidation of sulfide minerals and by human activities continuously recharges the groundwater,promoting the dissolution of carbonate rock and silicate rock in the process.

Production Characteristics and the Control Factors of Surface Wells for Relieved Methane Drainage in the Huainan Mining Area

Based on the production data of a large number of surface drainage wells in the Huainan mining area,the present study shows that four types of typical production characteristics for relieved methane wells are recognized,of which the stable type for production and gas concentration is the most dominate,as determined by a comprehensive study on the volume and concentration of drained gases, as well as the stress changes of rocks influenced by mining.Some influence factors for the productive differences of the drainage wells were also been discussed.The results indicate that protective coal-seam mining has a significant effect on overlying strata,which promotes the development of pores and fractures of coal reservoirs for methane desorption and migration;however,the production and the stability of drainage wells are affected by deformation and damage of the overlying strata.The second distribution of strata stress is caused by mining engineering,and if the stress load is larger than the carrying capacity of the extraction well,the gas production would be influenced by the drainage well that has been damaged by rock movement.Furthermore,the case damage occurs first in the weak, lithologic interface by its special mechanical properties.The stability of drainage wells and the production status are also influenced by the different drilling techniques,uneven distribution of gas concentration,and combination of gob gas and methane from the protected layer.

Exploitation technology of pressure relief coalbed methane in vertical surface wells in the Huainan coal mining area

Exploitation technology of pressure relief coalbed methane in vertical surface wells is a new method for exploration of gas and coalbed methane exploitation in mining areas with high concentrations of gas, where tectonic coal developed. Studies on vertical surface well technology in the Huainan Coal Mining area play a role in demonstration in the use of clean, new energy resources, preventing and reducing coal mine gas accidents and protecting the environment. Based on the practice of gas drainage engineering of pressure relief coalbed methane in vertical surface wells and combined with relative geological and exploration en- gineering theories, the design principles of design and structure of wells of pressure relief coalbed methane in vertical surface wells are studied. The effects of extraction and their causes are discussed and the impact of geological conditions on gas production of the vertical surface wells are analyzed. The results indicate that in mining areas with high concentrations of gas, where tectonic coal developed, a success rate of pressure relief coalbed methane in surface vertical well is high and single well production usually great. But deformation due to coal exploitation could damage boreholes and cause breaks in the connection between aquifers and bore-holes, which could induce a decrease, even a complete halt in gas production of a single well. The design of well site location and wellbore configuration are the key for technology. The development of the geological conditions for coalbed methane have a significant effect on gas production of coalbed methane wells.

Case study on the extraction of land cover information from the SAR image of a coal mining area

In this study,analyses are conducted on the information features of a construction site,a cornfield and subsidence seeper land in a coal mining area with a synthetic aperture radar (SAR) image of medium resolution. Based on features of land cover of the coal mining area,on texture feature extraction and a selection method of a gray-level co-occurrence matrix (GLCM) of the SAR image,we propose in this study that the optimum window size for computing the GLCM is an appropriate sized window that can effectively distinguish different types of land cover. Next,a band combination was carried out over the text feature images and the band-filtered SAR image to secure a new multi-band image. After the transformation of the new image with principal component analysis,a classification is conducted selectively on three principal component bands with the most information. Finally,through training and experimenting with the samples,a better three-layered BP neural network was established to classify the SAR image. The results show that,assisted by texture information,the neural network classification improved the accuracy of SAR image classification by 14.6%,compared with a classification by maximum likelihood estimation without texture information.

Study on the change rule of groundwater level and its impacts on vegetation at arid mining area

The shallow groundwater in Shendong mining area was broken because of large-scale underground mining activities. Selecting 32201 working-face as research area, analyzed the change rule of groundwater level and aquifer thickness under mining impact with a large number of water level observation data. Then, the impacts of groundwater level change on vegetation were analyzed by the relationship theory of arid area groundwater and vegetation. The results show that the aquifer structure and the water condition of supply flow and drainage are changed by the water proof mining. The groundwater level recovere only a little compared with the original groundwater level in two years. But the great change of groundwater level do not have notable influences on vegetation of this mining area, and further study indicates that there are certain conditions where groundwater level change impacted on vegetation. When the influence of groundwater level change was evaluated, the plant ecological water level, warning water level and spatial distribution character of original groundwater and mining-impacted groundwater-level change should be integrated.

Investigating spatial and temporal variations of soil moisture content in an arid mining area using an improved thermal inertia model

Mining operations can usually lead to environmental deteriorations. Underground mining activities could cause an extensive decrease in groundwater level and thus a dramatic variation in soil moisture content（SMC）. In this study, the spatial and temporal variations of SMC from 2001 to 2015 at two spatial scales（i.e., the Shendong coal mining area and the Daliuta Coal Mine） were analyzed using an improved thermal inertia model with a long-term series of Landsat TM/OLI（TM=Thematic Mapper and OLI=Operational Land Imager） data. Our results show that at large spatial scale（the Shendong coal mining area）, underground mining activities had insignificant negative impacts on SMC and that at small spatial scale（the Daliuta Coal Mine）, underground mining activities had significant negative impacts on SMC. Trend analysis of SMC demonstrated that areas with decreasing trend of SMC were mainly distributed in the mined area, indicating that underground mining is a primary cause for the drying trend in the mining region in this arid environment.

Migration and speciation transformation mechanisms of mercury in undercurrent zones of the Tongguan gold mining area, Shaanxi Loess Plateau and impact on the environment

In order to study the migration and transformation mechanism of Hg content and occurrence form in subsurface flow zone of gold mining area in Loess Plateau and its influence on water environment,the field in-situ infiltration test and laboratory test were carried out in three typical sections of river-side loess,alluvial and proluvial strata in Tongguan gold mining area of Shaanxi Province,and the following results were obtained:(1)The source of Hg in subsurface flow zone is mainly caused by mineral processing activities;(2)the subsurface flow zone in the study area is in alkaline environment,and the residual state,iron and manganese oxidation state,strong organic state and humic acid state of mercury in loess are equally divided in dry and oxidizing environment;mercury in river alluvial or diluvial strata is mainly concentrated in silt,tailings and clayey silt soil layer,and mercury has certain stability,and the form of mercury in loess is easier to transform than the other two media;(3)under the flooding condition,most of mercury is trapped in the silt layer in the undercurrent zone where the sand and silt layers alternate with each other and the river water and groundwater are disjointed,and the migration capacity of mercury is far less than that of loess layer and alluvial layer with close hydraulic connection;(4)infiltration at the flood level accelerates the migration of pollutants to the ground;(5)the soil in the undercurrent zone is overloaded and has seriously exceeded the standard.Although the groundwater monitoring results are safe this time,relevant enterprises or departments should continue to pay attention to improving the gold extraction process,especially vigorously rectify the small workshops for illegal gold extraction and the substandard discharge of the three wastes,and intensify efforts to solve the geological environmental problems of mines left over from history.At present,the occurrence form of mercury in the undercurrent zone is relatively stable,but the water and soil layers have been polluted.The risk of disjointed groundwater pollution can not be ignored while giving priority to the treatment of loess and river alluvial landform areas with close hydraulic links.The research results will provide a scientific basis for water conservancy departments to groundwater prevention and control in water-deficient areas of the Loess Plateau.

The evaluation of ecosystem health in mining areas on the matter element method

According to the characteristics of ecosystem and concept of the ecosystem in mining area, the index system of the ecosystem health in mining area was set up, and the evaluation standard was established. Aiming at the complexion in which the information lost in index ration, the matter element method was put forward to evaluate the ecosystem health in mining area. Making use of the model set up, the weight was built up by the method of index number heavy, the matter element, clas- sical field, and limit field were set up. The rating hierarchy was calculated by relating function. As a case study in the mining area of Pingyangsi Town, the results show that the ecosystem is good and sustainable from 2003 to 2006, but the healthy degree is not high, and some indexes have depravation.

Design of Landscape Ecological Restoration for “Five Mining Areas” of the Laoqing Mountain in the Dianchi Lake Basin

Through analyzing basic conditions of the "five mining areas" in the Laoqing Mountain of the Dianchi Lake Basin, in Kunming City, South China, the ecological restoration design of "integrating engineering protection and biological restoration, building the landscape ecological security pattern of the Laoqing Mountain" was proposed. Considering the different ecological functional areas, varying engineering measures, greening patterns, and irrigation means were selected for the ecological restoration, including site management, vegetation restoration, management and utilization etc.. These ecological restoration measures will produce favorable ecological benefits, and also take landscape effect and sustainable development into consideration, which will contribute to the ecological restoration of the "five mining areas", and provide a scientific and feasible reference for the ecological restoration in China.

SOME KEY ISSUES ON THE APPLICATION OF SATELLITE REMOTE SENSING TO MINING AREAS

In order to apply Satellite Remote Sensing (RS) to mining areas, some key issues should be solved. Based on an introduction to relative studying background, related key issues are proposed and analyzed oriented to the development of RS information science and demands of mining areas. Band selection and combination optimization of Landsat TM is discussed firstly, and it proved that the combination of Band 3, Band 4 and Band 5 has the largest information amount in all three-band combination schemes by both N-dimensional entropy method and Genetic Algorithm (GA). After that the filtering of Radarsat image is discussed. Different filtering methods are experimented and compared, and adaptive methods are more efficient than others. Finally the classification of satellite RS image is studied, and some new methods including classification by improved BPNN(Back Propagation Neural Network) and classification based on GIS and knowledge are proposed.

A New Discovery on the Deformation Behavior of Shale Gas Reservoirs Affecting Pore Morphology in the Juhugeng Coal Mining Area of Qinghai Province, Northwest China

Objective The Juhugeng mining area in Qinghai Province of northwest China has attracted wide attention among geologists for it hosts typical coal measure gases.The shale gas reservoirs were reformed by intensive structural movements during geological periods,

Failure characteristics of surface vertical wells for relieved coal gas and their influencing factors in Huainan mining area

Based on data from through-hole and logging,we studied the failure characteristics of surface drainage wells for relieved coal gas in Huainan mining area and its influencing factors.The results show that the damaged positions of drainage wells are mainly located at the thick clay layer in the low alluvium and the lithological interface in the upper section of bedrock in west mining area.The failure depth of casing is 244-670 m and concentrates at about 270-460 m deep.These damaged positions are mainly located in the bending zone according to three zones of rock layers in the vertical section above the roof divided. Generally,the casing begins to deform or damage before the face line about 30-150 m.Special formation structure and rock mass properties are the direct causes of the casing failure,high mining height and fast advancing speed are fundamental reasons for rock mass damage.However,the borehole configuration and spacing to the casing failure are not very clear.

CO emission in the air return corner of the working face in shallow burial mining areas

In shallow burial mining areas, abnormal CO emission and the spontaneous combustion of coal are great threats to safety production at a fully-mechanised working face. In order to prevent the CO concentration in the air return corner from exceeding the critical limit, the paper studied the CO emission regularity and characteristics through theoretical analysis, experimental research and field observation. The results show that the main sources of CO emission were the spontaneous combustion of coal in the goaf and the exhaust emissions coming from underground motorised vehicles. The effect factors of CO emission were also investigated, such as seasonal climate changes, the advancing distance and advancing speed of the working face, the number of underground motorised vehicles and some other factors. In addition to these basic analyses, the influence mechanism of each influence factor was also summarised theoretically. Finally, this study researched the distribution and change law of CO concentration in the fully-mechanised working face in two aspects: controlling the change of monitoring points and time respectively. The research results provide a theoretical basis for preventing the CO concentration from exceeding the critical limit in the air return corner and reducing the possibility of spontaneous combustion of coal. Additionally, the results also provide important theoretical and practical guidelines for protecting miners' health in modern mines featuring high production and high efficiency all over the world.

Use of the area of main influence to fix a relevant boundary for mining damages in Germany

In 2010, the fracking discussion in Germany caused a number of changes in German law, which came into force in 2016.Especially the production of gas had to be regulated.With the legislation amendment, the Subsidence-Area Mining Regulation has been revised, too.The changes expand the compensation of mining damages, especially to the extraction with drilling from the surface and underground storage.Although the Subsidence-Area Mining Regulation has been revised, the area of main influence(subsidence of 10 cm)remains to determine a relevant boundary for mining damages.The determination and prediction of this boundary above caverns are presented in this paper.In addition, further elements of ground movements and their relevance to mine damages are analyzed.The usage of the area of main influence to fix a relevant boundary for mining damages does not correspond to the relevant elements of ground movements.A limit for differences in subsidence(tilt) or horizontal changes in length should be preferred to describe the relevance of mining damages on buildings.Furthermore, this paper outlines the meaning of using the area of main influence to fix a relevant boundary for mining damages.

Spatial distribution and ecological risk of heavy metals and their source apportionment in soils from a typical mining area, Inner Mongolia, China

Determining the distributions and sources of heavy metals in soils and assessing ecological risks are fundamental tasks in the control and management of pollution in mining areas.In this study,we selected 244 sampling sites around a typical lead(Pb)and zinc(Zn)mining area in eastern Inner Mongolia Autonomous Region of China and measured the content of six heavy metals,including cuprum(Cu),Zn,Pb,arsenic(As),cadmium(Cd),and chromium(Cr).The ecological risk of heavy metals was comprehensively evaluated using the Geo-accumulation index,Nemerow general pollution index,and potential ecological risk index.The heavy metals were traced using correlation analysis and principal component analysis.The results showed that the highest content of heavy metals was found in 0–5 cm soil layer in the study area.The average content of Zn,As,Pb,Cu,Cr,and Cd was 670,424,235,162,94,and 4 mg/kg,respectively,all exceeding the risk screening value of agricultural soil in China.The areas with high content of soil heavy metals were mainly distributed near the tailings pond.The study area was affected by a combination of multiple heavy metals,with Cd and As reaching severe pollution levels.The three pathways of exposure for carcinogenic and noncarcinogenic risks were ranked as inhalation>oral ingestion>dermal absorption.The heavy metals in the study area posed certain hazards to human health.Specifically,oral ingestion of these heavy metals carried carcinogenic risks for both children and adults,as well as noncarcinogenic risks for children.There were differences in the sources of different heavy metals.The tailings pond had a large impact on the accumulation of Cd,Zn,and Pb.The source of Cr was the soil parent material,the source of As was mainly the soil matrix,and the source of Cu was mainly the nearby Cu ore.The purpose of this study is to more accurately understand the extent,scope,and source of heavy metals pollution near a typical mining area,providing effective help to solve the problem of heavy metals pollution.

Sustainable Development around Small Scale Mining Areas by the Development of Micro Hydro Power: Application Cases in Cameroon

Of all the precious metals buried in the Cameroonian subsoil, gold is certainly the longest exploited. It has longtime been the subject of artisanal exploitation. In 2014, the monthly national production was estimated at around 170 kg. In these mining areas, people still live in a screaming precariousness of which one of the main causes is often the lack of electricity, because of the distance of these localities to the national electricity network. Cameroon has a great hydroelectric potential, but the access rate to electricity is still very low in isolate or rural areas of this country. The objective of this work is to show that it is possible to efficiently exploit gold in isolated areas and contribute to the sustainable development of these localities through the development of micro hydro power (MHP). The mining community of Tikondi in the East Region of Cameroon is the practical case study for an illustration. The results of this study show that the development of the MHP project can be developed with installed power of 87 kW, where the Banki-Michell turbine is recommended according to the Sulzer-Escher Wyss diagram. The investment cost evaluated at 79,832,775 FCFA (1 Euro = 656 FCFA). It is a profitable project with a maximum payback period of 8 years. This project can be easily funded by gold mining activity. That Tikondi’s MHP can make this village becoming attractive for others activities, improving the quality of education of children (there is not any school and lots of them do not go to school), the building of health centers and the quality of life in that locality and therefore contribute to their sustainable development too.

The environment of coal mining areas and the economic evaluation of the land reclamation

The environment impact of the coal resources mining was analyzed. The method of economic evaluation for the coal mining was established to analyze land destruction. The opportunity cost method was used to quantitatively analyze and estimate the economic loss of the land destruction by coal mining. At the same time, the dump land reclamation of the Yuanbaoshan Open Pit was taken as an example to evaluate environmental and economical benefit with the method of economic evaluation for the coal mining areas land reclamation.

APPLICATION OF HIERARCHY ARTIFICIAL NEURAL NETWORK TO EVALUATE THE EXPLOITATIONCONDITIONS OF SURFACE MINING AREA

It always adopts the direct hierarchy analysis to value the exploitation conditions of surface mining areas. This way has some unavoidable shortcomings because it is mainly under the aid of experts and it is affected by the subjective thinking of the experts. This paper puts forwards a new approach that divides the whole exploitation conditions into sixteen subsidiary systems and each subsidiary system forms a neural network system. The whole decision system of exploitation conditions of surface mining areas is composed of sixteen subsidiary neural network systems. Each neural network is practiced with the data of the worksite, which is reasonable and scientific. This way will be a new decision approach for exploiting the surface mining areas.

STUDY ON THE TECTONIC STRESS FIELDS OF MESO-CENOZOIC IN LU'AN MINING AREA BY FINITE-ELEMENT SIMULATION

The structural de formation of Lu’ an mining area is characterized by a remarkable feature of zoning along E-W direction, in the east limb of Qinshui basin, Shanxi Province, China. The re gional tectonic stress fields and basement tectonics are two fundamental factors to control the cover tectonic framework. This paper uses the finite-element method with a elastic-plastic pIan problem model to simulate the three periods of stress fields resulting from field geological study’ Based on these works, the formation and evolution of tectonic framework of Lu’ an mining area have been discussed.

Heavy Metal Risk Assessment of Soils and Crops in the Intensive Mining Area of Gejiu, Yunnan Province

In order to investigate the heavy metal contamination of soil-crop in mining-intensive areas of Gejiu stannary in Yunnan Province and its risk to human health, the single-factor contamination index method and the Nemero comprehensive contamination index method were used to evaluate the contamination risk of heavy metals (Cd and As) in the soil of mining-intensive areas, and the health risk evaluation model was used to study the risk brought by residents through the consumption of maize, wheat and broad beans. The results showed that the mean values of total As and Cd in the soil of the study area were 146 and 2.32 mg·kg-1, which were 8 and 10.5 times higher than the background values of soil environment in Yunnan Province and belonged to heavy pollution;the enrichment coefficients of As and Cd in maize were 0.1% and 5.7%, in wheat were 0.3% and 11.5%, in fava beans were 0.1% and 4.9%;the soil contamination indices in the four study areas of A, B, C, and D were 7.275, 6.797, 5.618, and 5.060, respectively. The results indicated that the soils in the study areas belonged to heavy contamination levels, and the enrichment ability of Cd in all three crops was stronger than that of As, with wheat being the strongest, As in the three crops and Cd in broad beans might be harmful to children. As in wheat and broad beans may be harmful to adults.