CHINA MINE ENGINEERING

Abstract:With the implementation of the national standards on classification of solid mineral resources reserves, the estimation of ore reserves and the compilation of reserves disclosure report will become the direction of key study and focus by Chinese mining industrial personnel. Based on the authors understanding of the relevant international rules of CRIRSCO and JORC, in this article, emphasis is put on the study of the reserves estimation process under international rules; the priority content in reserves disclosure report and the requirements on the pre-feasibility study or feasibility study supporting the reserves disclosure report are put forward, and by combining with the authors' own project examples, the compilation of reserves disclosure report is explained, and suggestions are made for the development of Chinese reserves estimation and compilation of reserves disclosure report.

Abstract:In order to improve the safety reliability of the ventilation-and-three-preventions system of coal mines, in this article, the safety assessment of the ventilation-and-three-preventions system of coal mine is divided into three hierarchies of A, B and C to establish the safety assessment system of ventilation-and-three-preventions system, and to prescribe the division of safety assessment hierarchies of ventilation-and-three-preventions system of coal mine. Aiming at the project status of a certain mine in Shanxi Province, calculation is conducted for the indicator weight of various hierarchies of system by using the improved fuzzy analytic hierarchy process, according to affiliation, the relative weight of the lowest layer indicators relative to the safety indicators of ventilation-and-three-preventions is calculated out, by combining with the expert scoring method, the assessment is carried out qualitatively and quantitatively for the safety level of the ventilation-and-three-preventions system of the mine, with suggestions being given. The results show that by using the improved fuzzy analytic hierarchy process to assess the safety system of ventilation-and-three-preventions of the mine, the rating is that the system is relatively safe, and improvement can be preferentially made for the indicators that have relatively large weight and have lower rating; by using this method, the safety assessment can be quantitatively made for the ventilation-and-three-preventions system of coal mine in a simple and accurate way, which has provided a good train of thought for the safety assessment of ventilation-and-three-preventions of coal mine.

Abstract:Aiming at the issue of deformation and failure of high altitude soft broken large section roadway, the main belt conveyor roadway of Julong Copper Mine in Tibet is taken as the research subject. By using digital simulation software, the digital model is established to research the stress distribution status, displacement evolution law and plastic zone distribution law of the belt roadway and its wall rock during the excavation process, and the mechanism on deformation and failure of high altitude soft broken large section belt roadway is elaborated. The results show that the overall stress distribution of the belt roadway at the fracture zone is small, the wall rock displacement increase continuously, the failure mode is shear failure with larger range of failure, which is easy to make the belt roadway unstable. For this reason, the reasonable supporting method for the belt conveyance roadway at this position is put forward to meet the needs for the safe and efficient mining in the mine.

Abstract:Ore bin is an important channel for ore sliding conveyance, it is often damaged by ore impact, which severely affect the normal production of the mine. On the basis of ore movement trajectory and energy conversion and conservation principle, detailed analysis is conducted for the damage mechanism of ore bin wall. Aiming at the repair conditions of the transfer ore bin of a certain mine in China, four feasible technical options for reinforcement are put forward, detailed analysis is made for the pros and cons of various technical options, and the lateral comparison is conducted for the affecting extent of various factors. The optimal option fitting the mine actual conditions is obtained and applied to the practical use. The application results show that using this technical option can remarkably reduce the phenomenon of broken damage of ore bin wall so that the goal of protecting ore bin is achieved and the safe production of the mine is realized, which has a certain practical significance and engineering value for improving the buffer design of the ore bin of the mine and the production management.

Abstract:By analyzing the problems in the underground drift advancement process in Tonglushan Mine, comparison is made for the cut processes of medium-length hole, the reamer bit for drift advancement is introduced and made, the distribution of cut holes for drift advancement is optimized, and the site application test is conducted, so that the efficiency of the underground drift advancement in Tonglushan Mine is improved by 15%, and the material cost for advancement is reduced by 7%; in addition, the blasting effect of advancement construction is effectively improved and the safety and efficiency of site construction is improved.

Abstract:The new 1^# ore fines recovery shaft of Longshou Mine has been run for many years, the underground environment is damp, the elevator cab and shaft bottom facilities are severely rusty, the elevator cannot meet the requirement on safe production operation due to frequent failures; the rock integrity near the shaft is poor, the geostress is large, some local sections are misplaced and deformed, so an overhaul is badly needed; through tech-economical argumentation, decision is made that the elevator shaft is upgraded and the single rope winding type cage shaft is selected. In this article, emphasis is put on the discussion of construction process in terms of upgrading scheme and construction technology, the mutual impacts between production and construction are minimized. The practical and reliable safety assurance measures are taken to ensure the smooth completion of the project, which are both cost saving and time saving, and have accumulated valuable experience for future upgrading and utilizing waste and old mining shafts.

Abstract:The gold content of the cyanogen-bearing tailings from a certain gold mine in Inner Mongolia is 0.7g/t; in order to comprehensively recover the valuable gold in the tailings, based on the study of process mineralogy, through mineral processing test, the determination is made that the process route of Cyanide Tailings-Pretreatment-Valuable Elements Recycling-Identification with Tailings-Qualified Disposal is used to recycle the cyanide tailings. The tailings after treatment that are identified as general solid waste are discharged into the tailings pond to be stockpiled and disposed, the tailings pond is built according to the requirements for disposing general solid wastes. The test results show that when the cyanide concentration in the cyanide tailings slurring phase is ≤10mg/L, the reagents of CG101-A and CG101-B are added with the amount of 0.5g/L and 0.6g/L respectively, which can lower the cyanide in the cyanide tailings slurring phase and toxic leachate to below 0.5mg/L. By using flotation process flow, the gold concentrate of 5.78g/t Au-grade and of 62.99% recovery can be obtained; the separation indicators are ideal, which can provide a certain reference for the comprehensive recovery of the secondary resources of this type of gold tailings.

Abstract:In this article, tests are conducted to obtain the physical properties, chemical properties, size composition and basic properties of the full-tailings of a certain mine, and also conducted for the full-tailings settleability test, uniaxial compressive strength test and rheological behavior test. The test results show that when the cement-sand ratio of the tailings backfilling slurry is 1〖DK〗∶4~1〖DK〗∶6 and the slurry concentration is 68%~72%, the fill mass has good uniaxial compressive strength and flowing property. The optimal parameters for design of mine backfilling with mineral processing tailings are elaborated. The production capacity with mine backfilling method and the solid wastes disposal capacity can be improved, which can provide a reference for backfilling design of similar mines.

Abstract:In order to research the effect of faults on the stability of roadway wall rock, in this article, the return air laneways of 201 and 203 working faces of a certain mine are used as the engineering background, the FLAC3D digital simulation method is used to research the morphological distribution features and stress field distribution features of roadway wall rock plastic zone to reveal the law of strata behaviors of the return air laneways of 201 and 203 working faces under joint affect of mining and faults. The research result shows that the wall rock plastic zone where the roadway passes through the fault section has remarkable uneven distribution features, and failures occur in the shallow wall rock of roadway, with unloading phenomenon, and remarkable stress concentration zone is gradually formed in the deep wall rock; the failure morphology of wall rock plastic zone where the coal pillar passes through fault section is relatively uniform, and the distribution range of maximum principal stress of roadway wall rock seems to be symmetrically distributed. Aiming at the severe failure where the wall rock passes through fault section, the corresponding reinforced supporting solution is put forward based on the existing supporting method to effectively control the deformation of wall rock.

Abstract:The method of gob-side entry retaining of waste filling working face plays an important role in the technology of non-pillar mining in coal mines, which is widely used in mining thin and medium thickness coal seams, nevertheless, the roof weighting is still drastic, and the entry retaining effect is poor. In order to further perfect the wall rock control technology of gob-side entry retaining of working face in actual engineering application, and to reduce the entry retaining cost, the 11101 working face is used as the background, through engineering site practice, the wall rock structure of gob-side entry retaining in waste rock mining, the stress process of entry retaining wall rock, the wall rock deformation and the movement features of overburden are analyzed; and based on the results of stress analysis of entry retaining wall rock and the wall rock control principles of gob-side entry retaining of waste filling working face, the Anchor Cable+Reinforcing Rock Bolt and other solutions are rolled out. The monitoring system is designed to monitor the deformation of entry retaining wall rock and the bearing performance of the separating wall of entry retaining. The site monitoring results show that the deformation of the haulage drift is small, within the controllable range, which means that the entry retaining is successful and can provide a reference for using the entry retaining wall rock control technology under similar conditions.

Abstract:In order to more deeply analyze the law of overburden movement under repeated mining of shallow coal seam, the UDEC digital simulation method is used to conduct the simulated mining of the 1# and 2# seams of a certain coal mine in Shanxi Province; finally, the laws of overburden movement and fissure evolution under repeated mining of shallow coal seam are obtained, which is verified by means of two-dimensional physical similarity simulation test. The results show that after the 1# coal seam is mined, the working face first weighting step distance is 30m, for each excavation of approximate 10m, a periodic weighting is formed and the step distance of periodic weighting is 10m; similarly, after the 2# coal seam is mined, the working face first weighting step distance is 40m, for each excavation of approximate 10m, a periodic weighting is formed and the step distance of periodic weighting is 10m. It can be seen that the step distance of the first weighting of the working face of 2# coal seam is larger than that of the working face of 1# coal seam; after the mining of 1# coal seam is completed, the maximum displacement of the direct roof of 1# coal seam is 1.6m, the fissure zone is about 20m high and the roof-fall zone is about 5m; after the mining of 2# coal seam is completed, the maximum displacement of the direct roof of 1# coal seam is 3.2m, the maximum displacement of the direct roof of 2# coal seam is 1.8m, the fissure zone is about 73.5m high and the roof-fall zone is about 15m.

Abstract:For the waste rock, tailings and other solid wastes from mining and processing operations of mine, some of them are used for backfilling the mined-out area, the majority of the solid wastes are disposed on the ground mainly by means of building tailings pond, waste dump and tailings dry stacking. The stacking of solid waste occupies a large mass of land, pollutes the surrounding environment, is easy to result in tailings dam break, waste dump slide and other safety accidents and severely damage the harmony of the ecological environment. In this article, the train of thought on building a kind of waste-free, tailings-free, ecological and intelligent gold mine is put forward. Harmless treatment,cascade recovery and resource recycling are carried out for the waste rock and tailings, the newly-built mine is not provided with tailings pond and waste dump, which reduces the generation of solid wastes from the production source, the thinking of solid wastes treatment of traditional mine is converted, meanwhile, additional benefits are added to the enterprise, which meets the needs for sustainable development of ecological mining industry.

Abstract:The earthquake in mine is induced by mining activities, the correlation between the two is the important content in mine earthquake study; therefore, the research on the correlation between the temporal-spatial strong activity law during mine earthquake activities and the mining activities in the mine is not only the need of mine practice, but also an important means to further predict earthquake disasters. The micro-seismic monitoring system of NFC Africa Mining is the first overseas use of Chinese micro-seismic monitoring system, NFC Africa Mining is a demonstration mine of China in Africa, and also a large scale mine doing deep mining, so the research on the correlation between the micro-seismic activities and the blasting disturbance is of great significance. Based on the micro-seismic event signal and the blasting disturbance event signal detected by the micro-seismic monitoring system in the southeast orebody of NFC Africa Ming, in this article, the research on the correlation between the two events is carried out in terms of time, space and strength, which can provide powerful support for the study on technology of ground pressure control in deep mining, and can also provide guidance for the safe production of the mine and ensure the safety of personnel and equipment.

Abstract:For the purpose of exploring the solution of construction organization design for treatment project of municipal road mined-out area, the municipal roads in a certain city of Shanxi Province are taken as the background for the research; the research is conducted in terms of construction organization structure, construction process flow, key construction steps, construction precautions and other aspects. The research shows that the core of the mined-out area treatment is that there must be reasonable and detailed construction organization design, only in this way can the problems of safety, quality, progress, etc. arising from the mined-out treatment process be handled. In addition, in the mined-out area treatment project, the grouting time intervals, grouting ending-pressure, grouting saturation and other precautions must be clearly prescribed. Based on the analysis on the factors affecting the construction schedule, the measures and plan that ensure and control the construction progress are put forward, and the key precautions during the whole construction process are given.

Abstract:Sand-gravel aggregate is an indispensable material for infrastructure construction sector with the largest consumption, which is closely related to the construction and development of the country. Aiming at the situation that the present demand for the sand-gravel aggregate is ever increasing, in this article, summary is conducted for the typical processes and main process equipment of sand-gravel aggregate commonly seen in China, which can provide a reference for the process design of sand-gravel aggregate.

Abstract:The drive of the belt conveyor in the working face and mining area of the 13th panel of Bayangaole Coal Mine adopts frequency conversion control and runs at a constant speed of 4.0m/s. The rated transport capacity of the belt conveyor far exceeds the actual capacity of the working face, and the energy-saving function of the frequency converter cannot be fully However, the transportation system has problems of high energy consumption and serious wear and tear. For this reason, according to the situation of the belt transportation site in the 13-panel area, an intelligent speed regulation control system is proposed. Monitor; combine BP neural network and genetic algorithm to determine the best matching relationship between belt and coal flow, and realize intelligent speed regulation of belt conveyor through fuzzy control. After the on-site application, the energy consumption and wear of the 13-panel belt conveyor can be significantly reduced, and more significant application results have been achieved.