The study aimed at assessing the distribution and composition of dust produced at Pomona Stone Quarry mine in Harare, Zimbabwe. The source contribution to ambient PM2.5 and PM10 dust levels were quantified and their s...The study aimed at assessing the distribution and composition of dust produced at Pomona Stone Quarry mine in Harare, Zimbabwe. The source contribution to ambient PM2.5 and PM10 dust levels were quantified and their spatial distribution from the quarry to the receptor (community). The study also analysed the pH of soils around the mine, SiO2 and Al2O3 levels in quarry dust. Data was collected through direct observations, personal communications, experiments, soil and dust sampling and analyses. Dust sampling was done in January, April and August, to assess the effect of meteorological conditions on dust concentrations in two phases. Phase 1 was conducted during plant shut down (baseline measurements) while phase 2 was carried out during full plant operations (normal operating conditions), to assess the effect of quarry operations on the surrounding areas. Within the quarry production processes, crushing stage was the most dust emitting stage. Phase 1 dust results showed that both respirable (PM2.5) and inhalable (PM10) dust at all stages were below the legal limit, thus below 35 mg/m3 (respirable) and 180 mg/m3 (inhalable). Highest dust levels (209.9 mg/m3 inhalable and 69.01 mg/m3 respirable) were recorded in August, followed by April (206.9 mg/m3 inhalable and 67.52 mg/m3 respirable) then January (206.82 mg/m3 inhalable and 65.27 mg/m3 respirable). At all stages, highest dust concentrations for both parameters were recorded near the plant and decreased with increasing distance from the plant ( ranging from 209.9 mg/m3 - 19.41 mg/m3 inhalable and 69.01 mg/m3 - 14.23 mg/m3 respirable). This was attributed to the effect of particle size. August recorded the biggest area for both parameters falling within the non-permissible category, followed by April then January. The findings also revealed that the quarry dust contained higher levels of SiO2 (0.752 mg/cm3) which were 7 times higher than the recommended 0.1 mg/cm3 (NSSA). Low Al2O3 levels of 0.102 mg/cm3 were recorded and this was considered as environmentally safe. Soils were slightly acidic-alkaline and the t-test results at 95% confidence interval showed no significant difference between the results from site A and B (p = 0.526). It was concluded that quarry dust from Pomona had no significant effects on soil pH but possible health impacts on the receiving community. The study recommended that dust suppression systems such as water sprays, vegetation, air nets and enclosed production process must be implemented to curb dust emissions.展开更多
Through the study on landscape reconstruction of abandoned quarry pits in mountainous area of Jiangzhe District, it was pointed out that it was of not only practical significance but also ecological significance of su...Through the study on landscape reconstruction of abandoned quarry pits in mountainous area of Jiangzhe District, it was pointed out that it was of not only practical significance but also ecological significance of sustainable development to some extent, to scientifically and rationally rebuild and exploit abandoned quarry pits and to create new landscape, so that their landscape value and environmental benefit would entirely improve and that culture would be inherited and developed by making use of overt cultural fragments.展开更多
A quarry is a surface mining operated place, which produces enormous quantifies of gravel, limestone, and other materials for industrial and construction applications. Restoration and revegetation of deserted quarries...A quarry is a surface mining operated place, which produces enormous quantifies of gravel, limestone, and other materials for industrial and construction applications. Restoration and revegetation of deserted quarries are becoming increasingly important. Three areas of a typical quarry in South China： terrace for crushed materials （terrace）, spoiled mound, and remaining side slope, were investigated, to compare the existing plant species and to study the relationship between environmental factors and revegetation. The plant species composition of these three areas was found to differ significantly after eight years of natural recovery. The typical plant communities found over them were composed of gramineous herbs, ferns, and shrubs. Soil organic matter, soil moisture, and soil bulk density were considered to be the major determining factors for vegetation succession. There existed abiotic and biotic thresholds during quarrying restoration. Suggestions had been presented that could have accelerated the process of natural recovery in quarries.展开更多
The management of overburden is an important task in open pit exploitations. Site topography and morphology as well as geological and geotechnical properties of natural and remoulded materials are the most important f...The management of overburden is an important task in open pit exploitations. Site topography and morphology as well as geological and geotechnical properties of natural and remoulded materials are the most important factors affecting the disposal phase. Economic and environmental requirements must be followed in order to achieve the best reclamation results, keeping into account site constraints such as slope stability, hauling and dumping issues, and interactions with groundwater. This paper deals with the above mentioned issues, illustrating a rational approach applied on the case of a large limestone quarry where the thickness of the overburden is relevant and the spoil material has to be dumped in a flooded pit. The proposed multidisciplinary approach led to the selection of most suitable methods for excavation, transportation and disposal. The selection was based on a detailed laboratory and site characterisation that defined favorable and adverse factors to be considered during the preliminary study of a large quarrying project.展开更多
The performance of industrial waste incineration bottom ash in controlled low-strength material （CLSM） was investigated in this paper, as the quarry dust was added. CLSM mixtures were made from the industrial waste ...The performance of industrial waste incineration bottom ash in controlled low-strength material （CLSM） was investigated in this paper, as the quarry dust was added. CLSM mixtures were made from the industrial waste incineration bottom ash, quarry dust, and cement. Tests for fresh density, bleeding, compressive strength, shear strength, hydraulic conductivity, and excavatability were carried out. The com- pressive strength ranges from 60 kPa to 6790 kPa, the friction angle varies from 5°to 19°, and the cohesion is from 4 to 604 kPa. Most of the mixtures are found to be non-excavatable. It is indicated that the quarry dust addition increases the compressive strength and shear parame- ters, decreases bleeding, and increases the removability modulus.展开更多
The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yon...The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yongledian Quarry in Beijing.Through determination and analysis of soil physical and chemical properties,it shows that there are significant differences in the composite effects of soil physical and chemical properties between restored area,and undisturbed area,damaged area,and engineering restoration effectively improves the composite effects of soil physical and chemical properties in the restored area.The single factor hypothesis test shows that soil pH value,organic matter,alkali-hydrolyzable nitrogen,and total nitrogen traits are the key targets to be restored in this mining area.展开更多
The main objective of this study is to determine the rates of vertically and horizontally oriented drilling processes in marble quarries and to observe the factors affecting the drilling rates in terms of physical and...The main objective of this study is to determine the rates of vertically and horizontally oriented drilling processes in marble quarries and to observe the factors affecting the drilling rates in terms of physical and mechanical properties of the rocks. In situ drilling tests were performed in different marble quarries with different marble types and drilling times and penetration rates for a series of successive depthincrements were trying to be determined under vertically and horizontally oriented conditions. In order to understand the relation between the parameters that are investigated within the scope of this research, uniaxial compressive strength, Brazilian tensile strength, impact strength, Bohme abrasion strength, P-wave velocity, porosity, unit volume weight, Schmidt hardness index and brittleness index values were correlated with the drilling rates. It was noticed that the porosity and unit volume weight could be taken as the key parameters among them for obtaining meaningful correlation with drilling performance. It was also observed that the physical and mechanical rock properties are more relevant in vertical drilling than horizontal drilling.展开更多
Extraction of Limestone is an economically important and widespread activity in Ghana and has existed since historical times. However, in spite of its remarkable contribution towards economic development, some adverse...Extraction of Limestone is an economically important and widespread activity in Ghana and has existed since historical times. However, in spite of its remarkable contribution towards economic development, some adverse impacts have been noticed, especially where extraction is carried out without proper planning and use of modern technology and scientific methods. We have carried out an assessment on the environmental effects of limestone quarrying on some communities in the Lower Manya Krobo District in the Eastern region of Ghana. Dust emission is one of the major effects of the practice of limestone extraction and as such, dust (PM10) sampling was conducted at the affected communities. Mean dry season results recorded in these communities stand at 125.0 μg/m3 or Bueryonye, 116.0 μg/m3 at Odugblase and 109.3 μg/m3 at Klo-Begoro. Oterkpolu community which served as the control recorded an average of 50.5 μg/m3. Average rainy season values recorded for the communities were 83.3 μg/m3 for Bueryonye, 113.1 μg/m3 at Odugblase and 74.4 μg/m3 at Klo-Begoro. The control community, Oterkpolu, had 43.3 μg/m3. These values are above the EPA, Ghana daily guideline level of 70 μg/m3 over a time-weighted average per 24 hours. Questionnaires administration and health records obtained from the health facilities in the communities revealed notable deteriorations in the health of the people as a result of the quarrying activities in the area. Notable among these is the prevalence of malaria though not related to dust emissions, it results from mosquitoes breeding in the stagnant pools of water found in pits created as a result of the mining activity. Other common health cases recorded were acute respiratory tract infection, ear and eye infections, cough and pneumonia.展开更多
Long-term stability of large-span caverns is a challenging issue for design and construction of underground rock engineering.The Heidong cavern group consisting of 21 caverns was constructed about 1400 years ago for q...Long-term stability of large-span caverns is a challenging issue for design and construction of underground rock engineering.The Heidong cavern group consisting of 21 caverns was constructed about 1400 years ago for quarrying in massive Cretaceous tuff.The cavern No.5 of the Heidong cavern group is characterized by an unsupported span up to 92 m,with the overburden thickness of only 3-25 m.To analyze its long-term stability,a detailed investigation was conducted to obtain its geometry and rock mass characteristics,and to monitor surrounding rock displacements.Based on field survey and laboratory tests,numerical simulations were performed using the finite difference code FLAC;.The analysis results revealed that for the long-term stability of the cavern No.5,some major factors should be carefully considered,such as cavern excavation method in hard massive rocks,site investigation using trial pits,tools like short iron chisel and hammer for manual excavation,geometric dome roof,and waste rocks within abutment or on the floor.The highlights of the technologies obtained from this large-scale ancient underground project can provide reference for other similar project excavations in practice.展开更多
Quarrying is an activity contributing to the vitality of the Moroccan economy. However, most of these quarries were abandoned at the end of extraction and became dump and later a place of uncontrolled landfills. The n...Quarrying is an activity contributing to the vitality of the Moroccan economy. However, most of these quarries were abandoned at the end of extraction and became dump and later a place of uncontrolled landfills. The number of restored or rehabilitated quarries is limited and this threatens several aspects of the environment, especially, the quality of surface and ground water, landscape, forests, etc. This also gives rise to increased erosion risk. The study identifies plant species covering 10 abandoned quarries in the region of Rabat, especially the Bouregreg River and its affluent Akreuch in order to define a strategy for their restoration or rehabilitation. Field surveys were led to locate and map 10 abandoned quarries and to sample plant species. Herbaria were established and species were identified and classified. The results of the study distinguished 46 different plant species spread over 45 genera and 27 botanical families. The most dominant family in the quarries visited is Asteraceae. These results will allow us to study the vegetation dynamics in these abandoned lands and serve as a basis, in the selection of appropriate species in eventual restoration or rehabilitation projects.展开更多
Natural radionuclides content in granite from eight functional quarries in Osun State, Southwestern Nigeria was assessed. Eighty granite samples comprise?¾?inches.?½?inch and stone-dust were collec...Natural radionuclides content in granite from eight functional quarries in Osun State, Southwestern Nigeria was assessed. Eighty granite samples comprise?¾?inches.?½?inch and stone-dust were collected from Wolid, Slava, Ayofe, Espro, Ife/Modakeke, Krystal Vountein, Clario and Omidiran quarries in the State. Measurement was done using a high purity germanium (HPGe) detector. The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) software to determine if granite size has an impact on the activity concentrations. The results revealed that the mean activity concentrations of 238U (12.64 ± 1.89 Bq·kg -1) and 232Th (16.93 ± 2.46 Bq·kg -1) were highest in?¾?inch granite and lowest in stone-dust (5.01 ± 0.77 and 8.97 ± 1.37 Bq·kg -1 respectively), whereas 40K is highest in the ¾?inches (266.19 ± 35.53 Bq·kg -1) and lowest in?½?inches (151.85 ± 25.09 Bq·kg -1) granite. Espro has the highest (23.75 ± 3.74 Bq·kg -1) while Wolid has the lowest (4.11 ± 0.73 Bq·kg -1) 238U activity concentration and Slava has lowest for 232Th (8.21 ± 1.12 Bq·kg -1) and 40K (109.54 ± 11.06 Bq·kg -1). The radiological hazard parameters such as absorbed dose, annual effective dose radium equivalent, gamma index, external index, and internal index, were calculated to assess the radiation hazards associated with granite samples. The results obtained are lower than the recommended limits. The results were compared with the published data of other countries. Although, all the calculated radiation hazard indices were lower than the permissible limits. Therefore, people working in the quarries, granite end-users and the general public are safe from radiological health risks from the quarries, since there is no significant health hazard. The research will give reliable information on activity concentrations of natural radionuclides in granite rocks, contribute to a better understanding of radioactivity distribution in granite, and develop standards.展开更多
Quarrying of ornamental stone has adverse effects that are both visual and environmental. This paper aims to develop a methodology for minimising the costs associated with reducing the visual impact of ornamental ston...Quarrying of ornamental stone has adverse effects that are both visual and environmental. This paper aims to develop a methodology for minimising the costs associated with reducing the visual impact of ornamental stone quarrying. This study uses digital topographical maps of the study zone and a GPS and GIS application to calculate the extent of the area affected by quarrying activities for each altitude designated in the work plan and to calculate the extent of the potential visual impact. The results obtained applying the proposed methodology for the selected area suggested that the potential visual impact is minimal for an altitude of 520 metres, this being the optimal point for the observer. When altitude increases, the potential visual impact increases and the optimal point for the observer diminishes until the highest impact altitude (740 m) is readied. The optimal point that the exploitation should reach is that at which the values of the diagram generated by the (%) area of potential visual impact and area of exploitation (%) intersect. The methodology allows the optimal altitude to be determined for mining exploitations and helps assess the viability of a given exploitation from an environmental point of view.展开更多
Quarries are places of high instability due to blastings, if left without rehabilitation they become sites of great risk of rockfall, which are the case of the Carian quarry, a small abandoned aggregate quarry, which ...Quarries are places of high instability due to blastings, if left without rehabilitation they become sites of great risk of rockfall, which are the case of the Carian quarry, a small abandoned aggregate quarry, which turned into a slum neighborhood in the north western part of the city of Tétouan, and that has a long history of rockfall incidents since it was shut down in the 60’s. Using rockmass characterization techniques, kinematic study and stability analysis, it was confirmed that many instability mechanisms are found on the walls of the quarry and cause a high risk of rockfall during the rain season, especially that the study area is inhabited. Rockfall trajectory modelling techniques allow the calculation of vertical distribution of rocks falling from the quarry’s walls along different profiles in the area and therefore the determination of a safety perimeter from the quarry wall.展开更多
The paper presents a new method for preventing dust pollution in stone quarries using naphthenic wastes of petroleum refineries. The method is based on the use of naphthenate solutions of metals as wetting agents to m...The paper presents a new method for preventing dust pollution in stone quarries using naphthenic wastes of petroleum refineries. The method is based on the use of naphthenate solutions of metals as wetting agents to minimize dust release during stone-cutting process. The studies were carried out in one of the stone quarries of the Absheron peninsula. Initial experiments were conducted by using sodium-naphthenate (RCOONa) solution from alkali wastes of refineries. The results have shown that the use of RCOONa as wetting agent considerably reduces both dust pollution and energy consumption of the used equipment, while increasing the service life of stone-cutting saw. A series of researches were carried out with cupric naphthenate (RCOOCu) to further use the obtained dust-naphthenate mixture in agriculture. The effect of various parameters on the quality of the obtained product was investigated. The investigations have revealed that maximal dust reduction and the good quality of dust-naphthenate mixture were observed with 0.13% solution of RCOOCu at 11° - 13° angle of slope and 100 - 180 rotation∕min. intensity of conveyer.展开更多
The blasting practices in a limestone quarry with karstic cavities have beenpresented. The existence of karstic cavities in the quarry has reduced blasting efficiencysignificantly. In order to improve blasting efficie...The blasting practices in a limestone quarry with karstic cavities have beenpresented. The existence of karstic cavities in the quarry has reduced blasting efficiencysignificantly. In order to improve blasting efficiency different blasting strategies (loading holeswith ANFO in plastic bag, recording cavity location along the holes and charging the holes accordingto this information, and modifying blasting pattern according to karstic cavities) had beenimplemented and the results were evaluated on per ton cost basis. It was concluded that efficientblasting in such aquarries requires determining the size and shape of karstic cavities and based onthis information, to modify the blast pattern and charge the holes. The suggested method is torecord the cavity along the drill hole and to generate 3D model of cavities. By doing this, theproduction cost in the limestone quarry has decreased from 0.407 dollars/t to 0.354 dollars/t.展开更多
Geochemical investigation of the soils around quarry and barite mine sites in part of Akamkpa and Biase area of Southeastern Nigeria, was carried out to assess the concentration and enrichment levels of some heavy met...Geochemical investigation of the soils around quarry and barite mine sites in part of Akamkpa and Biase area of Southeastern Nigeria, was carried out to assess the concentration and enrichment levels of some heavy metals and trace elements in the soils. The investigation involved the collection of fifteen (15) soil samples between the depth of 15 - 30 cm. The samples were dried at room temperature, prepared and analyzed for heavy metals using inductively couple plasma mass spectrometer. The result shows that the concentration of Co, Cr, Nb, Pb and Sn were higher than the average shale values around the quarries while Ba, Pb and Sn were higher around the barite mines. The contamination factor indicates low to minimal contamination and low to considerable contamination around the quarries and barite mines respectively. While the Enrichment factor indicates minimal to significant enrichment around the quarries and minimal to extremely high enrichments around the barite mines. The result of the factor analysis and spatial distribution of the heavy metals suggests that the metal concentration and enrichment were controlled by the rock types, weathering and anthropogenic activities around the mine sites.展开更多
As such in any industrial raw material site characterization study, making a lithological evaluation for cement raw materials includes a description of physical characteristics as well as grain size and chemical compo...As such in any industrial raw material site characterization study, making a lithological evaluation for cement raw materials includes a description of physical characteristics as well as grain size and chemical composition. For providing the cement components in accordance with the specifications required, making the classification of the cement raw material pit is needed. To make this identification in a spatial system at a quarry stage, the supervised pattern recognition analysis has been performed. By using four discriminant analysis algorithms, lithological classifications at three levels, which are with limestone, marly-limestone (calcareous marl) and marl, have been made based on the main chemical components such as calcium oxide (CaO), alumina (Al2O3), silica (SiO2), and iron (Fe2O3). The results show that discriminant algorithms can be used as strong classifiers in cement quarry identification. It has also recorded that the conditional and mixed classifiers perform better than the conventional discriminant algorithms.展开更多
文摘The study aimed at assessing the distribution and composition of dust produced at Pomona Stone Quarry mine in Harare, Zimbabwe. The source contribution to ambient PM2.5 and PM10 dust levels were quantified and their spatial distribution from the quarry to the receptor (community). The study also analysed the pH of soils around the mine, SiO2 and Al2O3 levels in quarry dust. Data was collected through direct observations, personal communications, experiments, soil and dust sampling and analyses. Dust sampling was done in January, April and August, to assess the effect of meteorological conditions on dust concentrations in two phases. Phase 1 was conducted during plant shut down (baseline measurements) while phase 2 was carried out during full plant operations (normal operating conditions), to assess the effect of quarry operations on the surrounding areas. Within the quarry production processes, crushing stage was the most dust emitting stage. Phase 1 dust results showed that both respirable (PM2.5) and inhalable (PM10) dust at all stages were below the legal limit, thus below 35 mg/m3 (respirable) and 180 mg/m3 (inhalable). Highest dust levels (209.9 mg/m3 inhalable and 69.01 mg/m3 respirable) were recorded in August, followed by April (206.9 mg/m3 inhalable and 67.52 mg/m3 respirable) then January (206.82 mg/m3 inhalable and 65.27 mg/m3 respirable). At all stages, highest dust concentrations for both parameters were recorded near the plant and decreased with increasing distance from the plant ( ranging from 209.9 mg/m3 - 19.41 mg/m3 inhalable and 69.01 mg/m3 - 14.23 mg/m3 respirable). This was attributed to the effect of particle size. August recorded the biggest area for both parameters falling within the non-permissible category, followed by April then January. The findings also revealed that the quarry dust contained higher levels of SiO2 (0.752 mg/cm3) which were 7 times higher than the recommended 0.1 mg/cm3 (NSSA). Low Al2O3 levels of 0.102 mg/cm3 were recorded and this was considered as environmentally safe. Soils were slightly acidic-alkaline and the t-test results at 95% confidence interval showed no significant difference between the results from site A and B (p = 0.526). It was concluded that quarry dust from Pomona had no significant effects on soil pH but possible health impacts on the receiving community. The study recommended that dust suppression systems such as water sprays, vegetation, air nets and enclosed production process must be implemented to curb dust emissions.
文摘Through the study on landscape reconstruction of abandoned quarry pits in mountainous area of Jiangzhe District, it was pointed out that it was of not only practical significance but also ecological significance of sustainable development to some extent, to scientifically and rationally rebuild and exploit abandoned quarry pits and to create new landscape, so that their landscape value and environmental benefit would entirely improve and that culture would be inherited and developed by making use of overt cultural fragments.
文摘A quarry is a surface mining operated place, which produces enormous quantifies of gravel, limestone, and other materials for industrial and construction applications. Restoration and revegetation of deserted quarries are becoming increasingly important. Three areas of a typical quarry in South China： terrace for crushed materials （terrace）, spoiled mound, and remaining side slope, were investigated, to compare the existing plant species and to study the relationship between environmental factors and revegetation. The plant species composition of these three areas was found to differ significantly after eight years of natural recovery. The typical plant communities found over them were composed of gramineous herbs, ferns, and shrubs. Soil organic matter, soil moisture, and soil bulk density were considered to be the major determining factors for vegetation succession. There existed abiotic and biotic thresholds during quarrying restoration. Suggestions had been presented that could have accelerated the process of natural recovery in quarries.
文摘The management of overburden is an important task in open pit exploitations. Site topography and morphology as well as geological and geotechnical properties of natural and remoulded materials are the most important factors affecting the disposal phase. Economic and environmental requirements must be followed in order to achieve the best reclamation results, keeping into account site constraints such as slope stability, hauling and dumping issues, and interactions with groundwater. This paper deals with the above mentioned issues, illustrating a rational approach applied on the case of a large limestone quarry where the thickness of the overburden is relevant and the spoil material has to be dumped in a flooded pit. The proposed multidisciplinary approach led to the selection of most suitable methods for excavation, transportation and disposal. The selection was based on a detailed laboratory and site characterisation that defined favorable and adverse factors to be considered during the preliminary study of a large quarrying project.
基金the Ministry of Science, Technology and Innovation (MOSTI), Government of Malaysia and University of Malaya for providing the funds to support this research work
文摘The performance of industrial waste incineration bottom ash in controlled low-strength material （CLSM） was investigated in this paper, as the quarry dust was added. CLSM mixtures were made from the industrial waste incineration bottom ash, quarry dust, and cement. Tests for fresh density, bleeding, compressive strength, shear strength, hydraulic conductivity, and excavatability were carried out. The com- pressive strength ranges from 60 kPa to 6790 kPa, the friction angle varies from 5°to 19°, and the cohesion is from 4 to 604 kPa. Most of the mixtures are found to be non-excavatable. It is indicated that the quarry dust addition increases the compressive strength and shear parame- ters, decreases bleeding, and increases the removability modulus.
文摘The improvement of the soil physical and chemical properties is the most important foundation for mine ecological restoration.The experiment is aimed at undisturbed area,restored area,and damaged area of abandoned Yongledian Quarry in Beijing.Through determination and analysis of soil physical and chemical properties,it shows that there are significant differences in the composite effects of soil physical and chemical properties between restored area,and undisturbed area,damaged area,and engineering restoration effectively improves the composite effects of soil physical and chemical properties in the restored area.The single factor hypothesis test shows that soil pH value,organic matter,alkali-hydrolyzable nitrogen,and total nitrogen traits are the key targets to be restored in this mining area.
文摘The main objective of this study is to determine the rates of vertically and horizontally oriented drilling processes in marble quarries and to observe the factors affecting the drilling rates in terms of physical and mechanical properties of the rocks. In situ drilling tests were performed in different marble quarries with different marble types and drilling times and penetration rates for a series of successive depthincrements were trying to be determined under vertically and horizontally oriented conditions. In order to understand the relation between the parameters that are investigated within the scope of this research, uniaxial compressive strength, Brazilian tensile strength, impact strength, Bohme abrasion strength, P-wave velocity, porosity, unit volume weight, Schmidt hardness index and brittleness index values were correlated with the drilling rates. It was noticed that the porosity and unit volume weight could be taken as the key parameters among them for obtaining meaningful correlation with drilling performance. It was also observed that the physical and mechanical rock properties are more relevant in vertical drilling than horizontal drilling.
文摘Extraction of Limestone is an economically important and widespread activity in Ghana and has existed since historical times. However, in spite of its remarkable contribution towards economic development, some adverse impacts have been noticed, especially where extraction is carried out without proper planning and use of modern technology and scientific methods. We have carried out an assessment on the environmental effects of limestone quarrying on some communities in the Lower Manya Krobo District in the Eastern region of Ghana. Dust emission is one of the major effects of the practice of limestone extraction and as such, dust (PM10) sampling was conducted at the affected communities. Mean dry season results recorded in these communities stand at 125.0 μg/m3 or Bueryonye, 116.0 μg/m3 at Odugblase and 109.3 μg/m3 at Klo-Begoro. Oterkpolu community which served as the control recorded an average of 50.5 μg/m3. Average rainy season values recorded for the communities were 83.3 μg/m3 for Bueryonye, 113.1 μg/m3 at Odugblase and 74.4 μg/m3 at Klo-Begoro. The control community, Oterkpolu, had 43.3 μg/m3. These values are above the EPA, Ghana daily guideline level of 70 μg/m3 over a time-weighted average per 24 hours. Questionnaires administration and health records obtained from the health facilities in the communities revealed notable deteriorations in the health of the people as a result of the quarrying activities in the area. Notable among these is the prevalence of malaria though not related to dust emissions, it results from mosquitoes breeding in the stagnant pools of water found in pits created as a result of the mining activity. Other common health cases recorded were acute respiratory tract infection, ear and eye infections, cough and pneumonia.
基金financial support by the State Key Laboratory of Geohazard Prevention and Geoenvironment Protection,Chengdu University of Technology(Grant No.SKLGP2011K007)the Key Research Program of the Chinese Academy of Sciences(KZZD-EW05-02)the National Natural Science Foundation of China (Nos.41372324,40972198 and 41172269)
文摘Long-term stability of large-span caverns is a challenging issue for design and construction of underground rock engineering.The Heidong cavern group consisting of 21 caverns was constructed about 1400 years ago for quarrying in massive Cretaceous tuff.The cavern No.5 of the Heidong cavern group is characterized by an unsupported span up to 92 m,with the overburden thickness of only 3-25 m.To analyze its long-term stability,a detailed investigation was conducted to obtain its geometry and rock mass characteristics,and to monitor surrounding rock displacements.Based on field survey and laboratory tests,numerical simulations were performed using the finite difference code FLAC;.The analysis results revealed that for the long-term stability of the cavern No.5,some major factors should be carefully considered,such as cavern excavation method in hard massive rocks,site investigation using trial pits,tools like short iron chisel and hammer for manual excavation,geometric dome roof,and waste rocks within abutment or on the floor.The highlights of the technologies obtained from this large-scale ancient underground project can provide reference for other similar project excavations in practice.
文摘Quarrying is an activity contributing to the vitality of the Moroccan economy. However, most of these quarries were abandoned at the end of extraction and became dump and later a place of uncontrolled landfills. The number of restored or rehabilitated quarries is limited and this threatens several aspects of the environment, especially, the quality of surface and ground water, landscape, forests, etc. This also gives rise to increased erosion risk. The study identifies plant species covering 10 abandoned quarries in the region of Rabat, especially the Bouregreg River and its affluent Akreuch in order to define a strategy for their restoration or rehabilitation. Field surveys were led to locate and map 10 abandoned quarries and to sample plant species. Herbaria were established and species were identified and classified. The results of the study distinguished 46 different plant species spread over 45 genera and 27 botanical families. The most dominant family in the quarries visited is Asteraceae. These results will allow us to study the vegetation dynamics in these abandoned lands and serve as a basis, in the selection of appropriate species in eventual restoration or rehabilitation projects.
文摘Natural radionuclides content in granite from eight functional quarries in Osun State, Southwestern Nigeria was assessed. Eighty granite samples comprise?¾?inches.?½?inch and stone-dust were collected from Wolid, Slava, Ayofe, Espro, Ife/Modakeke, Krystal Vountein, Clario and Omidiran quarries in the State. Measurement was done using a high purity germanium (HPGe) detector. The statistical analysis was carried out using Statistical Package for Social Sciences (SPSS) software to determine if granite size has an impact on the activity concentrations. The results revealed that the mean activity concentrations of 238U (12.64 ± 1.89 Bq·kg -1) and 232Th (16.93 ± 2.46 Bq·kg -1) were highest in?¾?inch granite and lowest in stone-dust (5.01 ± 0.77 and 8.97 ± 1.37 Bq·kg -1 respectively), whereas 40K is highest in the ¾?inches (266.19 ± 35.53 Bq·kg -1) and lowest in?½?inches (151.85 ± 25.09 Bq·kg -1) granite. Espro has the highest (23.75 ± 3.74 Bq·kg -1) while Wolid has the lowest (4.11 ± 0.73 Bq·kg -1) 238U activity concentration and Slava has lowest for 232Th (8.21 ± 1.12 Bq·kg -1) and 40K (109.54 ± 11.06 Bq·kg -1). The radiological hazard parameters such as absorbed dose, annual effective dose radium equivalent, gamma index, external index, and internal index, were calculated to assess the radiation hazards associated with granite samples. The results obtained are lower than the recommended limits. The results were compared with the published data of other countries. Although, all the calculated radiation hazard indices were lower than the permissible limits. Therefore, people working in the quarries, granite end-users and the general public are safe from radiological health risks from the quarries, since there is no significant health hazard. The research will give reliable information on activity concentrations of natural radionuclides in granite rocks, contribute to a better understanding of radioactivity distribution in granite, and develop standards.
文摘Quarrying of ornamental stone has adverse effects that are both visual and environmental. This paper aims to develop a methodology for minimising the costs associated with reducing the visual impact of ornamental stone quarrying. This study uses digital topographical maps of the study zone and a GPS and GIS application to calculate the extent of the area affected by quarrying activities for each altitude designated in the work plan and to calculate the extent of the potential visual impact. The results obtained applying the proposed methodology for the selected area suggested that the potential visual impact is minimal for an altitude of 520 metres, this being the optimal point for the observer. When altitude increases, the potential visual impact increases and the optimal point for the observer diminishes until the highest impact altitude (740 m) is readied. The optimal point that the exploitation should reach is that at which the values of the diagram generated by the (%) area of potential visual impact and area of exploitation (%) intersect. The methodology allows the optimal altitude to be determined for mining exploitations and helps assess the viability of a given exploitation from an environmental point of view.
文摘Quarries are places of high instability due to blastings, if left without rehabilitation they become sites of great risk of rockfall, which are the case of the Carian quarry, a small abandoned aggregate quarry, which turned into a slum neighborhood in the north western part of the city of Tétouan, and that has a long history of rockfall incidents since it was shut down in the 60’s. Using rockmass characterization techniques, kinematic study and stability analysis, it was confirmed that many instability mechanisms are found on the walls of the quarry and cause a high risk of rockfall during the rain season, especially that the study area is inhabited. Rockfall trajectory modelling techniques allow the calculation of vertical distribution of rocks falling from the quarry’s walls along different profiles in the area and therefore the determination of a safety perimeter from the quarry wall.
文摘The paper presents a new method for preventing dust pollution in stone quarries using naphthenic wastes of petroleum refineries. The method is based on the use of naphthenate solutions of metals as wetting agents to minimize dust release during stone-cutting process. The studies were carried out in one of the stone quarries of the Absheron peninsula. Initial experiments were conducted by using sodium-naphthenate (RCOONa) solution from alkali wastes of refineries. The results have shown that the use of RCOONa as wetting agent considerably reduces both dust pollution and energy consumption of the used equipment, while increasing the service life of stone-cutting saw. A series of researches were carried out with cupric naphthenate (RCOOCu) to further use the obtained dust-naphthenate mixture in agriculture. The effect of various parameters on the quality of the obtained product was investigated. The investigations have revealed that maximal dust reduction and the good quality of dust-naphthenate mixture were observed with 0.13% solution of RCOOCu at 11° - 13° angle of slope and 100 - 180 rotation∕min. intensity of conveyer.
文摘The blasting practices in a limestone quarry with karstic cavities have beenpresented. The existence of karstic cavities in the quarry has reduced blasting efficiencysignificantly. In order to improve blasting efficiency different blasting strategies (loading holeswith ANFO in plastic bag, recording cavity location along the holes and charging the holes accordingto this information, and modifying blasting pattern according to karstic cavities) had beenimplemented and the results were evaluated on per ton cost basis. It was concluded that efficientblasting in such aquarries requires determining the size and shape of karstic cavities and based onthis information, to modify the blast pattern and charge the holes. The suggested method is torecord the cavity along the drill hole and to generate 3D model of cavities. By doing this, theproduction cost in the limestone quarry has decreased from 0.407 dollars/t to 0.354 dollars/t.
文摘Geochemical investigation of the soils around quarry and barite mine sites in part of Akamkpa and Biase area of Southeastern Nigeria, was carried out to assess the concentration and enrichment levels of some heavy metals and trace elements in the soils. The investigation involved the collection of fifteen (15) soil samples between the depth of 15 - 30 cm. The samples were dried at room temperature, prepared and analyzed for heavy metals using inductively couple plasma mass spectrometer. The result shows that the concentration of Co, Cr, Nb, Pb and Sn were higher than the average shale values around the quarries while Ba, Pb and Sn were higher around the barite mines. The contamination factor indicates low to minimal contamination and low to considerable contamination around the quarries and barite mines respectively. While the Enrichment factor indicates minimal to significant enrichment around the quarries and minimal to extremely high enrichments around the barite mines. The result of the factor analysis and spatial distribution of the heavy metals suggests that the metal concentration and enrichment were controlled by the rock types, weathering and anthropogenic activities around the mine sites.
文摘As such in any industrial raw material site characterization study, making a lithological evaluation for cement raw materials includes a description of physical characteristics as well as grain size and chemical composition. For providing the cement components in accordance with the specifications required, making the classification of the cement raw material pit is needed. To make this identification in a spatial system at a quarry stage, the supervised pattern recognition analysis has been performed. By using four discriminant analysis algorithms, lithological classifications at three levels, which are with limestone, marly-limestone (calcareous marl) and marl, have been made based on the main chemical components such as calcium oxide (CaO), alumina (Al2O3), silica (SiO2), and iron (Fe2O3). The results show that discriminant algorithms can be used as strong classifiers in cement quarry identification. It has also recorded that the conditional and mixed classifiers perform better than the conventional discriminant algorithms.
