为提高采场深孔掏槽爆破效率,改善VCR法深孔掏槽爆破效果,将VCR法掏槽爆破与中空孔直眼掏槽爆破相结合,首次尝试对中空孔VCR法深孔掏槽爆破进行机理分析,并在此基础上对其炮孔间距、装药长度、堵塞长度等掏槽参数进行了推导计算,得到其装药长度应为孔底堵塞长度的3~4倍。研究认为,在VCR法深孔掏槽爆破中增加中空孔,能够增加炮孔间距,增大爆腔体积,有效改善爆破效果。现场工程试验结果表明,爆破效果理想,块度均匀,单次掏槽高度约5m,爆破循环时间短,提高了掏槽效率,有利于矿房的高效回采。
In the process of producing potash fertilizer by a semi-autogenous grinding-cold crystallization-flotation process with the underground mined carnallite as raw material,it was found that semi-autogenous grinding efficiency is an important factor to restrict the effectiveness of subsequent cold crystallization-flotation process and also hindered the growth of yield.In order to enhance the capacity of the mill and the recovery of KCl,some measures are taken such as reducing the feed particle size,adjusting the mill filling rate and changing the mother liquor ratio in the normal operation of the mill.As a result,the mill capacity increased from 120t/h to 150t/h,content of+0.25 mm particle size fraction in the grinding product decreased by around 10%,the size distribution of cold crystallization products improved,the losses of pre-cast tailings reduced,the recovery of KCl increased by 2%,the yield of potash fertilizer increased by 60t/d on average.
In order to study the damage law of rock under the effect of blast shock,ultrasonic testing and CT imaging technology for limestone model were applied to do acoustic wave test and reconstruction of wave velocity distribution tests before and after the limestone blast without stemming under limestone model.The experimental results show that the radial damage of rock attenuation spread from the center of hole to its periphery,attenuation speed varied with the distance of surrounding rock from the blasting center,the damage declined rapidly at the position within3 times of the hole diameter from the center of hole.However,the damage declined slowly outside 3times of the hole diameter.The damage of axial of hole monotone decreased with the lower height of limestone mode,the maximum gradient was close to loading position and gradually leveled off.
The variety and phosphate releasing mechanism of phosphate-solubilizing microorganisms were summarized in this paper.The research practices of microbial solubilization of mid-low grade phosphate rocks using phosphate-solubilizing microorganisms in the last five years was listed,and the applied study on other ores by phosphate-solubilizing microorganisms was also specified.
Based on the application status of mining excavation acoustic emission and the shortage of the traditional acoustic emission evaluation method,the differential ratio indicator to evaluate and predict the stability of mining excavations on acoustic emission parameters is put forward,and the differential ratio formula is also given in this paper.Combined with the general changing of cumulative AE parameter in the instability of rock mass and application practice of AE in the eastern Hubei province,the general changing of differential ratio indicator and its precursor characteristics that corresponding to the general changing of AE are obtained.By applying the differential ratio indicator,the three AE parameters could be comprehensively taken into consideration,the inadequacy of traditional evaluation methods could be made up,and the impact of geological conditions and mining excavation layout could be reduced.By using the acoustic emission differential ratio,indicator could make the evaluation and prediction of mining excavation stability easy and effective.
The tailings of lead-zinc ore was used as original material with a certain amount of CuSO4 as activator,mixture of butyl xanthate and sodium dodecyl sulfonate as collector.The influences of the dosage of sodium silicate and sodium fluorosilicate which always used as the depressant of silicate on the grade of Fe as well as the recovery of pyrite were investigated.The results show that the grade of Fe of concentrate is increased from 16.69% to 26.88%,and the recovery of pyrite could reach 69%,when taking 1mg/mL sodium silicate 0.0075 mL,the grade of 30.58% Fe and the pyrite recovery of 61.33% were achieved when taking 1mg/mL sodium fluorosilicate 0.005 mL.The results of EMPA show that sodium fluorosilicate has good depression effect for silicate minerals.
Based on the occurrence characteristics of carnallite layers of a mine,a new mining method for solution mining by drilling was proposed and reasons to select solution mining and concrete implementing procedures are outlined.The method has advantages of safety,environmental protection,low investment cost and others and is considered as an ideal mining method for multilayer carnallite.
Melt-crystallization process with low energy consumption,less waste emissions and simple operation are drawing extensive attention in its application for phosphoric acid purification by wet process.It is divided into static and suspension method.In this paper,crystallization of impure phosphoric acid by the two methods were contrasted with temperature distribution,crystal morphology as well as effect of crystallized time on crystal yield,impurities removal efficiency of Fe3+and F-in crystallization autoclave in the process of static and suspension melt-crystallization process.The research showed that compared with the static crystallization process,products obtained by the suspension crystallization process are uniform and small in particle size.Moreover,the suspension process is less affected by time in crystallization and more efficient in eliminating Fe3+andF-and other impurities.
The systematic research is made of the direct preparation of phosphoric acid with the mid-low grade phosphate rocks in Jinning region in experiments.Taking the extraction rate of phosphorus iron-aluminum-magnesium as the main indicator,the effects of reaction temperature,the reaction time,the solid-liquid ratio and the SO3 concentration are researched and the optimum process conditions for acidolysis are obtained:reaction temperature being 80℃,reaction time 4h,the solid-liquid ratio 2∶1~2.5∶1,and concentration40g/L.Under this condition,when the validation test is conducted,the extraction rate of phosphorus can reach 94%.
In order to improve the evaluation precision of open-pit mine slope smooth blasting effect,to determine the optimal blasting scheme and the optimization of blasting parameters,the model of unascertained measure evaluation is set up.With the JDC open-pit mine 9smooth blasting as an example,the utilization factor of hole,hole mark rate and surface roughness of 3factors are used as the evaluation indexes to set up corresponding unascertained measurement function.The weight of each evaluation index is calculated by using the information entropy theory in accordance with the credible degree recognition criteria for classification.The unascertained importance vector is calculated to sort the sample project.The results show that the unascertained measure evaluation model is reasonable and reliable,simple and easy to master,providing a new method for the comprehensive evaluation of mine slope smooth blasting effect and the reliable basis for the selection of optimal blasting scheme and the optimization of blasting design parameters.
Tests were conducted by calcination-water quenching,grinding,acid leaching,washing,drying and other processes with wet purification,taking Hami vein quartz as material and oxalic acid as leaching agent.The best conditions of removing iron in Hami veinquartz obtained by the single factor and orthogonal tests are calcination-water quenching 1.5hat 950 ℃,ball milling 15 min at 2700r/min at running speed,acid leaching temperature 90℃and time 2.5h,acid concentration 0.1mol/L,pH value 2.5and ratio of solid to liquid 1∶3.The iron removal rate was≥98.46% and SiO2content≥ 99.86%in these conditions.
With Jianshan Phosphate Mine of Yunnan Phosphate Group Co.Ltd as the project background,this paper researched the optimization of stratified blasting technology for complex ore in open-pit mines.It analyzed the effect blasting vibration in the site tests had on buildings in the villages around Jianshan Phosphate Mine and optimized the existing blasting technology-related parameters according to the diversity of the geological conditions to ensure the blasting seismic wave by vibration lower than the one in national allowable safety standard for blasting vibration,not causing the damage to the houses.The blasting vibration geomechanical mathematical model for Jianshan Phosphate Mine was established.The extended model of rock mass blasting cumulative damage with reference quantity of reduction rate of velocity of sound for rock mass was built to study the damage effect of cumulative blast vibration for side slope,providing a reference for the subsequent mining operation to ensure the safety of side slope.
The great amount of test research was conducted on fluorite to address the technical difficulty of recovering the closely intergrown,fine grained and high impurity bearing fluorite ore.The tests of flotation conditions show that the fluorite recovery index is the most desirable with grinding fineness of-0.074mm85%,sodium carbonate dosage 2kg/t,T31 dosage 1.5kg/t,oleic acid dosage 300g/t and rough concentrate regrinding fineness-0.038 mm 94%.Also,research tests in a closed circuit were conducted and the final fluorite concentrates with 97.17% in grade and recovery 87.13% were obtained with the good flotation index.
Taking the phosphate mine of Yunnan Phosphate Chemical Group as instance,the paper discusses the methods for safety evaluation on open-pit phosphate mines.By analysis of the safety influence factors on the open-pit phosphate mine,a system of 28 indexes suitable for open-pit phosphate mine is established.By adopting the principle of analytic hierarchy process,the weighted value is determined and the comprehensive evaluations of each single factor and entirety of the open-pit phosphate mine by fuzzy mathematics method are made.The results show that the comprehensive safety status of Yunnan Phosphate Chemical Group's open-pit phosphate mine is overall desirable,consistent with the actual situations.
The orthogonal regression experiment on the mechanical properties of fill in Shirengou Iron Mine,two factors are cement sand ratio and curing time affiliated with three levels,and then make regression analysis of the experimental results,establishing the regression equation of the strength of cement sand ratio and curing time and providing the theories tools for that specific intensity of Backfilling to make the cement sand ratio quickly provided the theories tools.The establishment of the regression equation has provided the basic theoretical foundation for further understanding of the Mechanical Properties in Backfilling formation stage and researching on the Mechanism of Backfilling and Surrounding Rock.Also it has provided the basic model for studying the temporal variation laws of Backfilling.
The key problem of how to use the underground mined out area as underground space project is discussed to address the question of the underground mined out area being rebuilt into commercial underground space project in recent years.Especially in the long term stability of underground mined out area,based on the laboratory tests on rheological and disturbance causing damage to rock,the rock weakening rule is introduced in numerical simulation analysis of the long-term stability of underground mined out area and the problems needing attention and its solutions are proposed in the process of the underground mined out area being converted into underground space project.Also,the corresponding reinforcement and support ways for the rebuilding process and its subsequent operation are explored.
Multi-level indicators system of comprehensive benefits evaluation to mining enterprises was built to evaluate the comprehensive benefits of mining enterprises.Gray interval number was applied to describe each index in compliance with actual situations,grey range transform formula was adopted to standardize gray interval number indicators and gray interval associated cluster theory was introduced to make clustering analysis of comprehensive benefits of mining enterprises to produce the evaluation result of comprehensive benefits to mining enterprises.Gray Rough Set theory was taken to make rough approximation decision for analyzing the relationship between comprehensive benefits evaluation and its indicators.Practical examples show that the gray interval relational clustering model is able to evaluate the comprehensive benefits of mining enterprises,providing aguidance and reference for the efficient production of mining enterprises.
In this paper,with the main factors leading to the mine geological disasters as basis,combined with the mining method to be introduced in the mine,integrated use of AHP and fuzzy comprehensive evaluation method,the Shanghengshan Vanadium Mineu0027s geological disasters risk prediction is made with all kinds of geological disaster risk and comprehensive disasters risk rating for geological disasters in Shanghengshan Mine obtained,which has a significance for mining enterprises to make decisions on mining and to work out disasters prevention measures.
An experimental study method for millisecond blasting excavation of mine slope was proposed with Longxin No.1digital electronic detonator and numerical analysis was made of vibration velocity signals at different elevations using MATLAB 7.0.The results showed that change in the millisecond blasting vibration signal waveform shape was more sensitive to the delay time interval than the elevation difference,the total energy of millisecond blasting vibration signal was not only determined by velocity and the propagation medium of seismic wave acted as a natural filter,which significantly weakened the high-frequency signals compared with the low-frequency signals.With the higher elevation of measuring points,the signal energy concentrated toward the low-frequency.There was an optimal value of delay time interval in millisecond blasting,the distance(elevation)between measuring points(protected objects)and blasting area should be considered in selecting the optimal value of delay time interval.Under the experimental conditions,the optimal value of delay time interval between blasting holes of the rock slope was 15 ms.
Study was carried out of extracting boron from underground brine in Pingluo,Sichuan,using 2-butyl-2-ethyl-1,3-propanediol(BEPDO)as extractant,and chloroform as diluent.The condition experiments show that the optimal concentration of extractant is 1.0mol/L,the ratio of organic phase to brine is 1∶1,the extraction time is 10 min,and through atwo-stage extraction,the extraction rate reaches 99.35% while the extraction capacity reaches 44.25g/L(in terms of H3BO3).In the stripping process,sodium hydroxide is used as stripping agent.The stripping rate reaches 95.49 % under the optimal conditions:0.3mol/L sodium hydroxide,8 minutes stripping time,ratio of organic phase to stripping agent 1∶1,two-stage stripping.The recovery of boric acid reaches 94.87% after two-stage extracting and two-stage stripping under optimal conditions.
