Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of ro...Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.展开更多
Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar sur...Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar surface properties and solubility of semi-soluble salt-type minerals,pose significant challenges for the utilization of dolomite-rich magnesite resources.In this study,1-hydroxypropane-1,1-di phosphonic acid(HPDP)was identified for the first time as a high-performance depressant for dolomite.Various tests,including contact angle measurements,ζ potential analysis,X-ray photoelectron spectroscopy,and atomic force microscopy,were conducted to elucidate the interfacial interaction mechanisms of HPDP on the surfaces of the two minerals at different scales.Additionally,molecular modeling calculations were used to detail the spatial matching relationship between HPDP and the crystal faces of the two minerals.It was emphasized that HPDP specifically adsorbed onto the dolomite surface by forming calcium phosphonate,ensuring that the dolomite surface remained hydrophilic and sank.Moreover,it was found that the adsorption strength of HPDP on the mineral surfaces depended on the activity of the metal sites and their spatial distribution.These findings provide a theoretical foundation for the molecular design of flotation reagents for high-calcium magnesite ores.展开更多
The significant difference between the mechanical properties of soft rock and hard rock results in the complexity of the failure mode of the anti-dip layered slope with soft and hard rock interbedding.In order to reve...The significant difference between the mechanical properties of soft rock and hard rock results in the complexity of the failure mode of the anti-dip layered slope with soft and hard rock interbedding.In order to reveal the landslide mechanism,taking the north slope of Fushun West Open-pit Mine as an example,this paper analyzed the failure mechanism of different landslides with monitoring and field surveys,and simulated the evolution of landslides.The study indicated that when the green mudstone(hard rock)of the anti-dip slope contains siltized intercalations(soft rock),the existence of weak layers not only aggravates the toppling deformation of anti-dip layered slope with high dip,but also causes the shear failure of anti-dip layered slope with stable low dip.The shear failure including subsidence induced sliding and wedge failure mainly exists in the unloading zone of the slope.Its failure depth and failure time were far less than that of toppling failure.In terms of the development characteristics of deformation,toppling deformation has the long-term and progressive characteristics,but shear failure deformation has the abrupt and transient characteristics.This study has deepened the understanding of such slope landslide mechanism,and can provide reference for similar engineering.展开更多
The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable minerals.We investigated the effect of conditioning time on the separation of brucite and serpentine by flotation.B...The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable minerals.We investigated the effect of conditioning time on the separation of brucite and serpentine by flotation.By analyzing the Mg2+concentration,relative element content,and pulp viscosity,we studied the effect of mineral dissolution on brucite flotation.The results of artificially mixed mineral flotation tests(with-10μm serpentine)showed that by extending the conditioning time from 60 to 360 s,a large amount of Mg2+on the mineral surface gradually dissolved into the pulp,resulting in a decreased brucite recovery(from 83.83%to 76.79%)and an increased recovery of serpentine from 52.12%to 64.03%.To analyze the agglomeration behavior of brucite and serpentine,we used scanning electron microscopy,which clearly showed the different adhesion behaviors of different conditioning times.Lastly,the total interaction energy,as determined based on the extended DLVO(Derjaguin-Landau-Verwey-Overbeek)theory,also supports the conclusion that the gravitational force between brucite and serpentine increases significantly with increased conditioning time.展开更多
To investigate the zonal disintegration form of the surrounding rock in deep tunnels,model tests were performed in the simulation set-up of fracture mechanism and support technology of surrounding rock in deep tunnel....To investigate the zonal disintegration form of the surrounding rock in deep tunnels,model tests were performed in the simulation set-up of fracture mechanism and support technology of surrounding rock in deep tunnel.The test results illustrate that the first fracture of the surrounding rock occurred at the intersection of the tunnel floor and the side wall.After more serious destruction,the side wall and the vault were destroyed.Although the fracture width of each surrounding rock mass was distinct,they were relatively uniform with a nearly continuous fracture form.The width of the split bodies of the model tunnels(i.e.,the annular zonal disintegration area)developed with an increasing load.It was observed from the fitting curves of the data that all radial strain values of the surrounding rock were more symmetric with a smooth fitting curve,and the maximum value occurred near the tunnel wall before reducing instantly.The circumferential strain values were dispersed and the data were inconsistent with the fitting curve,which caused some data to be unreliable.The phenomenon of zonal disintegration was primarily caused by radial tension strain of the surrounding rock.This phenomenon would not extend indefinitely as the rupture range would be limited to a certain extent,because the maximum radial tension strain of the surrounding rock was less than the limiting value.展开更多
This study aims to predict the migration time of toxic fumes induced by excavation blasting in underground mines.To reduce numerical simulation time and optimize ventilation design,several back propagation neural netw...This study aims to predict the migration time of toxic fumes induced by excavation blasting in underground mines.To reduce numerical simulation time and optimize ventilation design,several back propagation neural network(BPNN)models optimized by honey badger algorithm(HBA)with four chaos mapping(CM)functions(i.e.,Chebyshev(Che)map,Circle(Cir)map,Logistic(Log)map,and Piecewise(Pie)map)are developed to predict the migration time.125 simulations by the computational fluid dynamics(CFD)method are used to train and test the developed models.The determination coefficient(R2),the variance accounted for(VAF),the Willmott’s index(WI),the root mean square error(RMSE),the mean absolute percentage error(MAPE),and the sum of squares error(SSE)are utilized to evaluate the model performance.The evaluation results indicate that the CirHBA-BPNN model has achieved the most satisfactory performance by reaching the highest values of R2(0.9945),WI(0.9986),VAF(99.4811%),and the lowest values of RMSE(15.7600),MAPE(0.0343)and SSE(6209.4),respectively.The wind velocity in roadway(Wv)is the most important feature for predicting the migration time of toxic fumes.Furthermore,the intrinsic response characteristic of the optimal model is implemented to enhance the model interpretability and provide reference for the relationship between features and migration time of toxic fumes in ventilation design.展开更多
Manganese ion(Mn^(2+))generated from metallurgical,steel making and chemical industries enters sewage treatment plants and affects the sludge activity and flocculation.The effect of Mn^(2+)on the removal of chemical o...Manganese ion(Mn^(2+))generated from metallurgical,steel making and chemical industries enters sewage treatment plants and affects the sludge activity and flocculation.The effect of Mn^(2+)on the removal of chemical oxygen demand(COD)and total phosphorus(TP)and sludge activity were investigated in anoxic zone of an anaerobic/anoxic/oxic(A2O)process.The compositions and structures of extracellular polymeric substances(EPS)were charac-terized using three-dimensional excitation emission matrix fluorescence spectroscopy(3D-EEM),X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FTIR)to reveal the relationship among Mn^(2+),EPS and sludge flocculation.The results showed thatlow concentration of Mn^(2+)(<5 mg/L)improved removal efficiencies of COD and TP and increased the activity of alkaline phosphatase,acid phosphatase and dehydrogenase.Meanwhile,the addition of Mn^(2+)increased total EPS,sludge contact angle,Zeta potential and sludge particle size,and thus enhanced sludge flocculation.However,high concentration of Mn^(2+)(>10 mg/L)hindered microbial flocculation and reduced removal efficiencies of the pollutants.When Mn^(2+)was 5 mg/L,removal efficiencies of COD and TP reached 65%and 90%,respectively.Sludge flocculation was the best and SVI was 70.56 mL//g.The changes of Mn^(2+)concentration caused deviation of groups'compositions in LB-EPS and TB-EPS,where the main components were always protein(PN)and polysaccharide(PS).The addition of Mn^(2+)resulted in the degradation of humic acids.However,it did not give rise to significant morphology changes of EPS.展开更多
Zhu Yuelian’s tomb has been exposed to groundwater for many years,and this exposure has caused many defects,including erosion,encrustation,patina,and spot marks related to groundwater,seriously affecting the artistic...Zhu Yuelian’s tomb has been exposed to groundwater for many years,and this exposure has caused many defects,including erosion,encrustation,patina,and spot marks related to groundwater,seriously affecting the artistic and ornamental value of cultural relics.In this study,high-density microelectrode spacing resistivity and ultrasonic transverse wave reflection were used to detect hidden damage in the burial chamber,and the results revealed hidden damage,corrosion,cracks,and pores in the surrounding geological body,concealed cracks in the sidewalls,and internal defects in the columns.An outdoor high-density resistivity test and hydrological observation experiment indicated that the tomb is located in a weakly permeable aquifer,and the groundwater head has been higher than the bottom of the tomb for many years.Natural groundwater flows from northeast to southwest in the aquifer,and the tomb forms an artificial concave cone,causing groundwater around the area to continually flow into the tomb.A chemical composition analysis of the groundwater and scale revealed that the groundwater within the tomb area is slightly corrosive,and the groundwater seepage along the fissures of the compacted layer induces damage.The threedimensional(3D)seepage numerical simulation results indicated that the combined use of drainage and impervious curtains can cause the water head in the curtain to drop significantly and control the water head to be lower than 8 m from the bottom floor of the tomb,meeting the requirements for seepage prevention and protection of the tomb without long-term maintenance.展开更多
基金supported by the National Key Research and Development Program of China(No.2022YFC2903902)the National Natural Science Foundation of China(Nos.52204080and 52174070)the Fundamental Research Funds for the Central Universities of China(No.2023GFYD17)。
文摘Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.
基金supported by the Fundamental Research Funds for the Central Universities(No.N2201005).
文摘Given the depletion of high-quality magnesite deposits and the rising demand for high-end magnesium materials,the separation and utilization of high-calcium magnesite ores have become essential.However,the similar surface properties and solubility of semi-soluble salt-type minerals,pose significant challenges for the utilization of dolomite-rich magnesite resources.In this study,1-hydroxypropane-1,1-di phosphonic acid(HPDP)was identified for the first time as a high-performance depressant for dolomite.Various tests,including contact angle measurements,ζ potential analysis,X-ray photoelectron spectroscopy,and atomic force microscopy,were conducted to elucidate the interfacial interaction mechanisms of HPDP on the surfaces of the two minerals at different scales.Additionally,molecular modeling calculations were used to detail the spatial matching relationship between HPDP and the crystal faces of the two minerals.It was emphasized that HPDP specifically adsorbed onto the dolomite surface by forming calcium phosphonate,ensuring that the dolomite surface remained hydrophilic and sank.Moreover,it was found that the adsorption strength of HPDP on the mineral surfaces depended on the activity of the metal sites and their spatial distribution.These findings provide a theoretical foundation for the molecular design of flotation reagents for high-calcium magnesite ores.
基金supported by the National Key Research and Development Program of China(Nos.2022YFC2903902 and 2022YFC2903903)the National Natural Science Foundation of China(Nos.U1903216 and 52174070).
文摘The significant difference between the mechanical properties of soft rock and hard rock results in the complexity of the failure mode of the anti-dip layered slope with soft and hard rock interbedding.In order to reveal the landslide mechanism,taking the north slope of Fushun West Open-pit Mine as an example,this paper analyzed the failure mechanism of different landslides with monitoring and field surveys,and simulated the evolution of landslides.The study indicated that when the green mudstone(hard rock)of the anti-dip slope contains siltized intercalations(soft rock),the existence of weak layers not only aggravates the toppling deformation of anti-dip layered slope with high dip,but also causes the shear failure of anti-dip layered slope with stable low dip.The shear failure including subsidence induced sliding and wedge failure mainly exists in the unloading zone of the slope.Its failure depth and failure time were far less than that of toppling failure.In terms of the development characteristics of deformation,toppling deformation has the long-term and progressive characteristics,but shear failure deformation has the abrupt and transient characteristics.This study has deepened the understanding of such slope landslide mechanism,and can provide reference for similar engineering.
基金financial support from the Project funded by the China Postdoctoral Science Foundation(No.2020M670709)the National Natural Science Foundation of China(No.51974064)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.N2101025)the Open Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2017-02)。
文摘The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable minerals.We investigated the effect of conditioning time on the separation of brucite and serpentine by flotation.By analyzing the Mg2+concentration,relative element content,and pulp viscosity,we studied the effect of mineral dissolution on brucite flotation.The results of artificially mixed mineral flotation tests(with-10μm serpentine)showed that by extending the conditioning time from 60 to 360 s,a large amount of Mg2+on the mineral surface gradually dissolved into the pulp,resulting in a decreased brucite recovery(from 83.83%to 76.79%)and an increased recovery of serpentine from 52.12%to 64.03%.To analyze the agglomeration behavior of brucite and serpentine,we used scanning electron microscopy,which clearly showed the different adhesion behaviors of different conditioning times.Lastly,the total interaction energy,as determined based on the extended DLVO(Derjaguin-Landau-Verwey-Overbeek)theory,also supports the conclusion that the gravitational force between brucite and serpentine increases significantly with increased conditioning time.
基金This work was financially supported by the Chinese National key R&D project(No.2016YFC0801402)the Chinese National Natural Science Foundation Project(No.51627804).
文摘To investigate the zonal disintegration form of the surrounding rock in deep tunnels,model tests were performed in the simulation set-up of fracture mechanism and support technology of surrounding rock in deep tunnel.The test results illustrate that the first fracture of the surrounding rock occurred at the intersection of the tunnel floor and the side wall.After more serious destruction,the side wall and the vault were destroyed.Although the fracture width of each surrounding rock mass was distinct,they were relatively uniform with a nearly continuous fracture form.The width of the split bodies of the model tunnels(i.e.,the annular zonal disintegration area)developed with an increasing load.It was observed from the fitting curves of the data that all radial strain values of the surrounding rock were more symmetric with a smooth fitting curve,and the maximum value occurred near the tunnel wall before reducing instantly.The circumferential strain values were dispersed and the data were inconsistent with the fitting curve,which caused some data to be unreliable.The phenomenon of zonal disintegration was primarily caused by radial tension strain of the surrounding rock.This phenomenon would not extend indefinitely as the rupture range would be limited to a certain extent,because the maximum radial tension strain of the surrounding rock was less than the limiting value.
基金The authors were funded by China Scholarship Council(Grant Nos.202106370038,and 201906690049)National Key Research and Development Program of China(Grant No.2021YFC3001300).
文摘This study aims to predict the migration time of toxic fumes induced by excavation blasting in underground mines.To reduce numerical simulation time and optimize ventilation design,several back propagation neural network(BPNN)models optimized by honey badger algorithm(HBA)with four chaos mapping(CM)functions(i.e.,Chebyshev(Che)map,Circle(Cir)map,Logistic(Log)map,and Piecewise(Pie)map)are developed to predict the migration time.125 simulations by the computational fluid dynamics(CFD)method are used to train and test the developed models.The determination coefficient(R2),the variance accounted for(VAF),the Willmott’s index(WI),the root mean square error(RMSE),the mean absolute percentage error(MAPE),and the sum of squares error(SSE)are utilized to evaluate the model performance.The evaluation results indicate that the CirHBA-BPNN model has achieved the most satisfactory performance by reaching the highest values of R2(0.9945),WI(0.9986),VAF(99.4811%),and the lowest values of RMSE(15.7600),MAPE(0.0343)and SSE(6209.4),respectively.The wind velocity in roadway(Wv)is the most important feature for predicting the migration time of toxic fumes.Furthermore,the intrinsic response characteristic of the optimal model is implemented to enhance the model interpretability and provide reference for the relationship between features and migration time of toxic fumes in ventilation design.
基金This work was supported by the National Natural Science Foundation of China(No.51678119)the Science and Technology Development Program of Jilin Province(No.20180201016SF).
文摘Manganese ion(Mn^(2+))generated from metallurgical,steel making and chemical industries enters sewage treatment plants and affects the sludge activity and flocculation.The effect of Mn^(2+)on the removal of chemical oxygen demand(COD)and total phosphorus(TP)and sludge activity were investigated in anoxic zone of an anaerobic/anoxic/oxic(A2O)process.The compositions and structures of extracellular polymeric substances(EPS)were charac-terized using three-dimensional excitation emission matrix fluorescence spectroscopy(3D-EEM),X-ray photoelectron spectroscopy(XPS)and Fourier transform infrared spectroscopy(FTIR)to reveal the relationship among Mn^(2+),EPS and sludge flocculation.The results showed thatlow concentration of Mn^(2+)(<5 mg/L)improved removal efficiencies of COD and TP and increased the activity of alkaline phosphatase,acid phosphatase and dehydrogenase.Meanwhile,the addition of Mn^(2+)increased total EPS,sludge contact angle,Zeta potential and sludge particle size,and thus enhanced sludge flocculation.However,high concentration of Mn^(2+)(>10 mg/L)hindered microbial flocculation and reduced removal efficiencies of the pollutants.When Mn^(2+)was 5 mg/L,removal efficiencies of COD and TP reached 65%and 90%,respectively.Sludge flocculation was the best and SVI was 70.56 mL//g.The changes of Mn^(2+)concentration caused deviation of groups'compositions in LB-EPS and TB-EPS,where the main components were always protein(PN)and polysaccharide(PS).The addition of Mn^(2+)resulted in the degradation of humic acids.However,it did not give rise to significant morphology changes of EPS.
基金supported by the National Key Research and Development Program(Grant Nos.2016YFC0801603 and 2017YFC1503105)Fundamental Research Funds for the Central Universities(Grant No.N2123030)the Key Projects for Technological Innovation and Application Development in Chongqing(Grand No.CSTB2022TIAD-KPX0095)。
文摘Zhu Yuelian’s tomb has been exposed to groundwater for many years,and this exposure has caused many defects,including erosion,encrustation,patina,and spot marks related to groundwater,seriously affecting the artistic and ornamental value of cultural relics.In this study,high-density microelectrode spacing resistivity and ultrasonic transverse wave reflection were used to detect hidden damage in the burial chamber,and the results revealed hidden damage,corrosion,cracks,and pores in the surrounding geological body,concealed cracks in the sidewalls,and internal defects in the columns.An outdoor high-density resistivity test and hydrological observation experiment indicated that the tomb is located in a weakly permeable aquifer,and the groundwater head has been higher than the bottom of the tomb for many years.Natural groundwater flows from northeast to southwest in the aquifer,and the tomb forms an artificial concave cone,causing groundwater around the area to continually flow into the tomb.A chemical composition analysis of the groundwater and scale revealed that the groundwater within the tomb area is slightly corrosive,and the groundwater seepage along the fissures of the compacted layer induces damage.The threedimensional(3D)seepage numerical simulation results indicated that the combined use of drainage and impervious curtains can cause the water head in the curtain to drop significantly and control the water head to be lower than 8 m from the bottom floor of the tomb,meeting the requirements for seepage prevention and protection of the tomb without long-term maintenance.
