The tectonic deformation image of Asia Continent can be explained successfully by the model of collision between India secondary continent and Euro\|Asia Plate (P. Molnar and P.Tapponnier, 1975). This paper mainly dis...The tectonic deformation image of Asia Continent can be explained successfully by the model of collision between India secondary continent and Euro\|Asia Plate (P. Molnar and P.Tapponnier, 1975). This paper mainly discusses the characteristics of tectonic deformation and strong earthquake activities on the east border of Tibet Plateau.1\ Characteristics of tectonic deformation on the east border of Tibet Plateau\;Controlled by the flow of the plateau crust material, the movement of the east border of Tibet plateau is mainly horizontal so as to produce two slipping\|block: one results from the slide out of Chuandian Rhombus Block along the SSE direction, the other results from the lateral extrusion of Chuanqing Block with the SEE direction. The slip rate of the north part of Chuandian Rhombus Block, the west region of Sichuan, is 5～8mm/a;2～3mm/a on the south part (the center part of Yunan); the slip rate of Chuanqing is 3～5mm/a and <1mm/a on Longmenshan region (Tang Rongchang, 1993). The slipping features of the blocks directly decide the movement characters of different fault systems: the uniform sinistral shear movement on the east boundary fault of Chuandian Rhombus Block, from the geological viewpoint, the average horizontal slip rate is about 10mm/a, and 5～8mm/a on the Anninghe, Zemuhe and Xiaojiang faults. The dextral shear movement can be found on the west boundary faults composed by Jinshajiang and Honghe faults. Located at the dextral diagonal region between Honghe and Zhongdian faults, the northwestern region of Yunnan shows a tensile stress field with near EW direction and large graben valleys with near NS direction on the ground due to the dextral slip movements of these two faults and slip of Chuandian Rhombus Block along the SSE direction. The normal features of extension tectonic deformation region can be found in this region. Some inner faults (such as Amaniqing, Xiqinglingbeilu) of Chuanqing block show the character of sinistral shear movement with some components of normal slip movement. As the east boundary of Tibet plateau, Minshan and Longmenshan Mountains form the east wall of the plateau. Contrasting to the moving direction of Chuanqing block, the transition from horizontal movement to vertical movement produced the huge nappe reverse deformation in this region, and formed some front\|Mount compensating press\|sag basins such as Gonggaling, Zhangla and Chengdu. Because of the diversity of slip rate of different boundary faults, some clockwise rotating movement can be found in different sub\|blocks.展开更多
Background:From 2007 to 2013,intensive control measures reduced malaria burden by 90%along the China-Myanmar border.However,despite these measures a P.falciparum malaria outbreak was reported in the Shan Special Regio...Background:From 2007 to 2013,intensive control measures reduced malaria burden by 90%along the China-Myanmar border.However,despite these measures a P.falciparum malaria outbreak was reported in the Shan Special Region II of Myanmar in June of 2014.Methods:Epidemiological,parasitological and entomological investigations were performed.Dihydroartemisinin piperaquine(DAPQ)was immediately administered to treat parasite positive individuals.Long lasting insecticidal nets(LLIN),indoor residual spraying(IRS)with insecticides and behavior change communication(BCC)were also provided for outbreak control.An embedded efficacy study was conducted evaluating DP.Molecular genotyping via polymerase chain reaction(PCR)was performed on the Kelch gene on chromosome 13.Results:All infections were identified as Plasmodium falciparum by RDT and microscopy.Two fatalities resulted from the outbreak.The attack rate was 72.8%(67/92)and the incidence density rate was 14.2 per 100 person-weeks.The positive rate of rapid diagnostic test(RDT)was 72.2%(65/90)and microscopically-determine parasite rate 42.2%(38/90).Adjusted odds ratio(OR)of multivariate logistic regression analysis for aged<15 years,15–45 years,inappropriate treatment from a private healer and lack of bed nets were 13.51(95%confidence interval,2.21–105.89),7.75(1.48–44.97),3.78(1.30–46.18)and 3.21(1.21–15.19)respectively.In the six surrounding communities of the outbreak site,positive RDT rate was 1.2%(4/328)and microscopically-determine parasite rate 0.6%(2/328).Two light traps collected a total of 110 anopheline mosquitoes including local vectors,An.minimus,An.sinensis and An.maculates.After intensive control,the detection of malaria attacks,parasites and antigen were reduced to zero between July 1 and December 1,2014.The cure rate of P.falciparum patients at day 42 was 94.3%(95%CI,80.8–99.3%).The PCR did not detect K13-propeller mutations.Conclusion:Imported P.falciparum caused the outbreak.Age,seeking inappropriate treatment and lack of bed nets were risk factors for infection during the outbreak.P.falciparum was sensitive to treatment with DAPQ.The integrated measures controlled the outbreak and prevented the spread of P.falciparum effectively.The results of this study indicate that malaria control on the China-Myanmar border,especially among special populations,needs further collaboration between China,Myanmar and international societies.展开更多
Current coal pillar design is the epitome of suspension design.A defined weight of unstable overburden material is estimated, and the dimensions of the pillars left behind are based on holding up that material to a pr...Current coal pillar design is the epitome of suspension design.A defined weight of unstable overburden material is estimated, and the dimensions of the pillars left behind are based on holding up that material to a prescribed factor of safety.In principle, this is no different to early roadway roof support design.However, for the most part, roadway roof stabilisation has progressed to reinforcement, whereby the roof strata is assisted in supporting itself.This is now the mainstay of efficient and effective underground coal production.Suspension and reinforcement are fundamentally different in roadway roof stabilisation and lead to substantially different requirements in terms of support hardware characteristics and their application.In suspension, the primary focus is the total load-bearing capacity of the installed support and ensuring that it is securely anchored outside of the unstable roof mass.In contrast, reinforcement recognises that roof de-stabilisation is a gradational process with ever-increasing roof displacement magnitude leading to ever-reducing stability.Key roof support characteristics relate to such issues as system stiffness, the location and pattern of support elements and mobilising a defined thickness of the immediate roof to create(or build) a stabilising strata beam.The objective is to ensure that horizontal stress is maintained at a level that prevents mass roof collapse.This paper presents a prototype coal pillar and overburden system representation where reinforcement, rather than suspension, of the overburden is the stabilising mechanism via the action of in situ horizontal stresses.Established roadway roof reinforcement principles can potentially be applied to coal pillar design under this representation.The merit of this is evaluated according to failed pillar cases as found in a series of published databases.Based on the findings, a series of coal pillar system design considerations for bord and pillar type mine workings are provided.This potentially allows a more flexible approach to coal pillar sizing within workable mining layouts, as compared to common industry practice of a single design factor of safety(Fo S) under defined overburden dead-loading to the exclusion of other relevant overburden stabilising influences.展开更多
Ensuring rib stability during pillar extraction is of prime importance in bord and pillar(B&P) method of underground coal mining with caving. Rib stability has been assessed here by way of assessing factor of safe...Ensuring rib stability during pillar extraction is of prime importance in bord and pillar(B&P) method of underground coal mining with caving. Rib stability has been assessed here by way of assessing factor of safety(FOS), a ratio of the strength of rib to stress on it. Earlier formulations for rib stability when applied to case studies gave very low FOS value suggesting significant ground control problems, which were contrary to the field observations. This has necessitated the need to revisit the concept of rib stability. The stress coming on the rib is estimated with the use of numerical modeling technique using the FLAC^(3D) software. The methodology of assessing rib-stability with the help of suggested rib-strength formulation has been validated at eight Indian coal mines. The outcome of this study finds relevance and importance in ensuring underground coal liquidation with improved safety and conservation.展开更多
The EGAT Mae Moh Mine is the largest open pit lignite mine in Thailand and it produces lignite about 16 million tons annually. In the near future, the pit limit of the mine will be reached and underground mine will th...The EGAT Mae Moh Mine is the largest open pit lignite mine in Thailand and it produces lignite about 16 million tons annually. In the near future, the pit limit of the mine will be reached and underground mine will then be developed through the open pit in the depth of 400 - 600 m from the surface. However, due to the challenges for underground mining such as poor geological conditions, extra thickness (20 - 30 m) of coal seams, and weak mechanical properties of coal seams and the surrounding rock, the success possibility of underground mining and an applicable underground mining method is being investigated at the present. The paper discusses the applicability of multi-slice bord-and-pillar method for the soft extra thick coal seams in the Mae Moh mine by means of numerical analyses using the 3D finite difference code “FLAC3D”.展开更多
文摘The tectonic deformation image of Asia Continent can be explained successfully by the model of collision between India secondary continent and Euro\|Asia Plate (P. Molnar and P.Tapponnier, 1975). This paper mainly discusses the characteristics of tectonic deformation and strong earthquake activities on the east border of Tibet Plateau.1\ Characteristics of tectonic deformation on the east border of Tibet Plateau\;Controlled by the flow of the plateau crust material, the movement of the east border of Tibet plateau is mainly horizontal so as to produce two slipping\|block: one results from the slide out of Chuandian Rhombus Block along the SSE direction, the other results from the lateral extrusion of Chuanqing Block with the SEE direction. The slip rate of the north part of Chuandian Rhombus Block, the west region of Sichuan, is 5～8mm/a;2～3mm/a on the south part (the center part of Yunan); the slip rate of Chuanqing is 3～5mm/a and <1mm/a on Longmenshan region (Tang Rongchang, 1993). The slipping features of the blocks directly decide the movement characters of different fault systems: the uniform sinistral shear movement on the east boundary fault of Chuandian Rhombus Block, from the geological viewpoint, the average horizontal slip rate is about 10mm/a, and 5～8mm/a on the Anninghe, Zemuhe and Xiaojiang faults. The dextral shear movement can be found on the west boundary faults composed by Jinshajiang and Honghe faults. Located at the dextral diagonal region between Honghe and Zhongdian faults, the northwestern region of Yunnan shows a tensile stress field with near EW direction and large graben valleys with near NS direction on the ground due to the dextral slip movements of these two faults and slip of Chuandian Rhombus Block along the SSE direction. The normal features of extension tectonic deformation region can be found in this region. Some inner faults (such as Amaniqing, Xiqinglingbeilu) of Chuanqing block show the character of sinistral shear movement with some components of normal slip movement. As the east boundary of Tibet plateau, Minshan and Longmenshan Mountains form the east wall of the plateau. Contrasting to the moving direction of Chuanqing block, the transition from horizontal movement to vertical movement produced the huge nappe reverse deformation in this region, and formed some front\|Mount compensating press\|sag basins such as Gonggaling, Zhangla and Chengdu. Because of the diversity of slip rate of different boundary faults, some clockwise rotating movement can be found in different sub\|blocks.
基金supported by The WHO Mekong Malaria Programme(WP/10/MVP/005837)the tenth grant to China of the Global Fund to fight AIDS,Tuberculosis and Malaria(GFATM/CHN-011-G15-M)+1 种基金China National Malaria Elimination Programme(CNMEP)supported by The National Natural Science Foundation of China(NSFC/81560543).
文摘Background:From 2007 to 2013,intensive control measures reduced malaria burden by 90%along the China-Myanmar border.However,despite these measures a P.falciparum malaria outbreak was reported in the Shan Special Region II of Myanmar in June of 2014.Methods:Epidemiological,parasitological and entomological investigations were performed.Dihydroartemisinin piperaquine(DAPQ)was immediately administered to treat parasite positive individuals.Long lasting insecticidal nets(LLIN),indoor residual spraying(IRS)with insecticides and behavior change communication(BCC)were also provided for outbreak control.An embedded efficacy study was conducted evaluating DP.Molecular genotyping via polymerase chain reaction(PCR)was performed on the Kelch gene on chromosome 13.Results:All infections were identified as Plasmodium falciparum by RDT and microscopy.Two fatalities resulted from the outbreak.The attack rate was 72.8%(67/92)and the incidence density rate was 14.2 per 100 person-weeks.The positive rate of rapid diagnostic test(RDT)was 72.2%(65/90)and microscopically-determine parasite rate 42.2%(38/90).Adjusted odds ratio(OR)of multivariate logistic regression analysis for aged<15 years,15–45 years,inappropriate treatment from a private healer and lack of bed nets were 13.51(95%confidence interval,2.21–105.89),7.75(1.48–44.97),3.78(1.30–46.18)and 3.21(1.21–15.19)respectively.In the six surrounding communities of the outbreak site,positive RDT rate was 1.2%(4/328)and microscopically-determine parasite rate 0.6%(2/328).Two light traps collected a total of 110 anopheline mosquitoes including local vectors,An.minimus,An.sinensis and An.maculates.After intensive control,the detection of malaria attacks,parasites and antigen were reduced to zero between July 1 and December 1,2014.The cure rate of P.falciparum patients at day 42 was 94.3%(95%CI,80.8–99.3%).The PCR did not detect K13-propeller mutations.Conclusion:Imported P.falciparum caused the outbreak.Age,seeking inappropriate treatment and lack of bed nets were risk factors for infection during the outbreak.P.falciparum was sensitive to treatment with DAPQ.The integrated measures controlled the outbreak and prevented the spread of P.falciparum effectively.The results of this study indicate that malaria control on the China-Myanmar border,especially among special populations,needs further collaboration between China,Myanmar and international societies.
文摘Current coal pillar design is the epitome of suspension design.A defined weight of unstable overburden material is estimated, and the dimensions of the pillars left behind are based on holding up that material to a prescribed factor of safety.In principle, this is no different to early roadway roof support design.However, for the most part, roadway roof stabilisation has progressed to reinforcement, whereby the roof strata is assisted in supporting itself.This is now the mainstay of efficient and effective underground coal production.Suspension and reinforcement are fundamentally different in roadway roof stabilisation and lead to substantially different requirements in terms of support hardware characteristics and their application.In suspension, the primary focus is the total load-bearing capacity of the installed support and ensuring that it is securely anchored outside of the unstable roof mass.In contrast, reinforcement recognises that roof de-stabilisation is a gradational process with ever-increasing roof displacement magnitude leading to ever-reducing stability.Key roof support characteristics relate to such issues as system stiffness, the location and pattern of support elements and mobilising a defined thickness of the immediate roof to create(or build) a stabilising strata beam.The objective is to ensure that horizontal stress is maintained at a level that prevents mass roof collapse.This paper presents a prototype coal pillar and overburden system representation where reinforcement, rather than suspension, of the overburden is the stabilising mechanism via the action of in situ horizontal stresses.Established roadway roof reinforcement principles can potentially be applied to coal pillar design under this representation.The merit of this is evaluated according to failed pillar cases as found in a series of published databases.Based on the findings, a series of coal pillar system design considerations for bord and pillar type mine workings are provided.This potentially allows a more flexible approach to coal pillar sizing within workable mining layouts, as compared to common industry practice of a single design factor of safety(Fo S) under defined overburden dead-loading to the exclusion of other relevant overburden stabilising influences.
文摘Ensuring rib stability during pillar extraction is of prime importance in bord and pillar(B&P) method of underground coal mining with caving. Rib stability has been assessed here by way of assessing factor of safety(FOS), a ratio of the strength of rib to stress on it. Earlier formulations for rib stability when applied to case studies gave very low FOS value suggesting significant ground control problems, which were contrary to the field observations. This has necessitated the need to revisit the concept of rib stability. The stress coming on the rib is estimated with the use of numerical modeling technique using the FLAC^(3D) software. The methodology of assessing rib-stability with the help of suggested rib-strength formulation has been validated at eight Indian coal mines. The outcome of this study finds relevance and importance in ensuring underground coal liquidation with improved safety and conservation.
文摘The EGAT Mae Moh Mine is the largest open pit lignite mine in Thailand and it produces lignite about 16 million tons annually. In the near future, the pit limit of the mine will be reached and underground mine will then be developed through the open pit in the depth of 400 - 600 m from the surface. However, due to the challenges for underground mining such as poor geological conditions, extra thickness (20 - 30 m) of coal seams, and weak mechanical properties of coal seams and the surrounding rock, the success possibility of underground mining and an applicable underground mining method is being investigated at the present. The paper discusses the applicability of multi-slice bord-and-pillar method for the soft extra thick coal seams in the Mae Moh mine by means of numerical analyses using the 3D finite difference code “FLAC3D”.
