CHINA MINE ENGINEERING

Abstract:The present models for evaluating the safety of underground trackless transportation in high altitude mines are less than well rounded. An attempt was made to evaluate the safety thereof in three aspects: the safety/unsafety of humans, transport equipment, and the environment, and a model was built to that effect, with parameters and standards developed for each facet, and weight assigned through the analytic hierarchy process (AHP). The model was further built following the fuzzy comprehensive evaluation (FCE) method to be a multi-factor-coupled man-machine-environment comprehensive safety evaluation model. This model was used in assessing the safety of a certain high altitude mine, and a score of 90.88 was reached, indicating sound safety of the mine.

Abstract:Laiwu Mining Group made a lot of explorations in applying backfilling technologies in the downward drifting process, and accumulated rich experience therein. The essay first introduces the downward drifting with paste backfilling process, then analyzes paste backfilling design and optimization schemes, focusing on the resolution of practical difficulties, including: netting suspension, filtrate containment and sealing, and backfilling stratification and top filling and connection.

Abstract:The sublevel stoping with post filling method has been continuously improved in the operation of Tongshankou Copper Mine, both in mining and backfilling. The method was applied consecutively in 6 stopes at Level -160m, with operation indicators markedly improved: ratio of cutting/preliminary development and mining tonnage reduced by 17m3/kt, overall dilution and loss rates reduced by 2.23% and 2.42%, stope production capacity improved by 80.5t/d, direct cost of stope operation reduced by 44.2 yuan/t. The optimization thus serves as a good reference for the promotion of the mining method.

Abstract:In recent years, mineral resources in the west plateau areas of China are being increasingly developed. Such developments not only strengthened national mineral resource security and boosted economic growth, but also brought rich experience for the development of mineral processing technologies in plateau environment. The essay is a summary of the development of these technologies and projects the trends forward.

Abstract:To achieve safety and high efficiency, the high-level large diameter long hole stoping process is adopted in Ashele Copper Mine. After investigating the country rock conditions and the potential forms of roof falling, long anchor bolts were adopted for the roof support design. Field testing revealed two types of falls, which are from the middle to sideways, and from down upwards. The form of anchor bolt support and support parameters were then determined: anchor bolts are 10-12m long, row intervals are at 2m, drill hole diameter 2-3 times as long as the anchor bolt diameter. Field pilot tests showed such support not only provides good control of the roofs, but significantly boosts economic benefits as well.

Abstract:The upper and lower iron ore layers in Gongchangling Iron Mine are apart only by 10m. The upper ore layer is first extracted and backfilled before the lower layer is mined. Due to the short upright interval, a large mined out area in the lower layer may affect the ground stability of the upper layer, posing a risk of falling interval rock pillars and backfilled material in the upper layer. A study was therefore conducted based on the mining design and the stope structural parameters, through the finite difference method. The study shows that when the upper layer is mined without backfilling, connections will form in the plastic zones of the interval rock pillars between the upper and lower layers, with tensile stress approximating 1MPa; when the mined areas of the upper layer are timely backfilled, however, no connections form in the plastic zones, with rather low tensile stress, and both the rock pillars and the stopes can remain stable.

Abstract:At the initial stage of gold mining, water source and supply is a major constraint to mine development and establishment. Based on history data, the study optimized the hydrogeological exploration scheme, improved the hydrogeological drilling and shaft extension process. A combination of water extraction and discharge experiments was conducted, and accurate hydrogeological data were obtained to evaluate the water resource underground, and finally the water source site was determined. The study contributed to the water sourcing process.

Abstract:Due to geological structures, some underground roadways tend to be fragmented. Such fragmentation gives rise to severe deformation, local damage, and even roof collapse, seriously affecting mining operation. The essay analyzes the causes for fragmented country rock deformation and break, studies the mechanism of grouting consolidation, and proposes a grouting scheme based on site actualities. The field deformation statistics revealed that the grouting consolidation effectively reduced porosity and improved the strength of fragmented country rocks, and brings roadway deformation under control. The practice serves as a good reference for the treatment of roadways of the same nature.

Abstract:The essay is a case study of 3109 haulage roadway development. To improve gas control efficiency, antireflection was conducted by applying directed hydraulic fracturing at the coal body in front of the workface. After theoretical analyses, project comparison and studying site gas control actualities, a directed hydraulic fracturing antireflection scheme was developed and practiced. Finally a remarkable success was achieved: gas extraction drilling purity and concentration were improved by 30% and 150%, and gas control time was reduced by about 1/3.

Abstract:To improve the coal recovery and reduce roadway development loads of Yanjiahe Coal Mine, gob-side entry retaining with pressure relief by roof cutting was proposed, and detailed design was conducted on providing supplementary support for leading constant resistance anchor bolts, relieving pressure by roof blasting, and workface rear side gangue supports. The application achieved good results: roof and side wall displacement numbered 50mm and 60mm only; apart from the marked entry retaining results, the air leakage in the retained areas are also up to the requirement.

Abstract:Great height, super long workface mining is the trend of coal mining in China. By increasing workface length, mining efficiency can be improved as the number of equipment turnarounds and losses from coal pillars are reduced. The essay is a case study of the super long workface mining at Wangzhuang Coal Mine. To reveal the mechanism of ground pressure occurrence and understand the parameters of the equipment running at the workface, a systemic study was carried out on the theories and technologies of great height, super long workface mining. The pressure patterns at super long workfaces were determined, and the mining equipment and processes were analyzed, forming a system of theories and technologies for great height, super long workface mining. The practice of the theories and technologies achieved great safety and efficiency, providing a good reference for future promotion.

Abstract:Some single main plant buildings of concentrator have large bays and the location selection of LV substation is limited. Meanwhile, most process equipment in the plant building belongs to LV equipment, whose system design is difficult to develop. Combining project practice, this paper introduces how to design the LV distribution system of this kind of plant building, which provides reference for the LV distribution design of similar plant buildings.

Abstract:The welding quality of the plate groove of the hydraulic support directly affects the quality of the whole hydraulic support. In order to meet the quality requirements of hydraulic support in current coal production industry, combining with the actual production of hydraulic support, this paper discusses on the optimization of groove welding process of structural members and plates of hydraulic support, the further standardization of groove cutting process and angle, and the groove inspection tooling to improve the manufacturing quality of high-end hydraulic support.

Abstract:Aiming at the problems of weak technology of monitoring system and untimely anti-collision early warning for large transport vehicles in open-pit mines, this paper puts forward the vehicle-mounted monitoring terminal C-V2X technology through the research and analysis on relevant technologies at home and abroad. The technology mainly realizes key functions such as overspeed alarm and anti-collision early warning through GNSS positioning, RF radio frequency and C-V2X vehicle networking technologies, making the operation of mining equipment more automatic and efficient, updating and managing the mine production process in time, and obtaining higher economic benefits.

Abstract:Based on the local hydrological manual, the flood calculation of a tailings pond is carried out, and the flood-regulating routing of the tailings pond is done by the water balance method. According to the calculation results, it is considered that the flood discharge capacity of the tailings pond meets the requirements of the code, which provides a reference for the recheck calculation of the flood discharge capacity of similar projects.

Abstract:In order to better solve the problems such as survey errors encountered in the mine survey process, a mine of Jinyongtai Coal Industry Co., Ltd. is taken as an example. Through optimizing and upgrading the mine survey technology, the links that produce survey errors are analyzed and the survey capability has been improved to ensure the smooth progress of the survey work. The results show that analyzing the error links in advance and controlling the error sources in time can effectively reduce the influence of survey errors on safety production and achieve good results.

Abstract:With the rapid development of China s national economy and the gradual expansion of power grid scale, power grids in some mining areas are no longer suitable for modern industrial power demand, which leads to poor operation of distribution systems in mining enterprises and drop of power factor and voltage of distribution networks. It is necessary to further optimize the energy distribution system of metal mine power grid and add dynamic energy compensation devices for real-time network tracking, so as to improve efficiency and energy quality and save operating costs.

Abstract:In order to improve the monitoring efficiency of roadway wall rock deformation, 3D laser scanning technology is applied, and the monitoring technical scheme and field monitoring results are analyzed and studied. The results show that the difference between the deformation rates of roadway wall rock obtained by 3D laser scanning technology and that obtained by conventional method is less than 5%, and the monitoring accuracy of wall rock deformation by 3D laser scanning technology is higher.

Abstract:Surveying and mapping is the basic work of mine coal resources mining. Adopting advanced surveying and mapping technology can not only improve efficiency, but also significantly reduce costs, providing reliable data support for efficient and safe mining of coal resources. In order to better promote the development of mine surveying and mapping work, the technical principles and mine application of modern surveying and mapping technologies such as total station, spatial information survey technology, inertial survey technology, and 3D laser scanning technology are analyzed and discussed, and the application characteristics of each surveying and mapping technology are summarized. The research results can promote the application of modern surveying and mapping technology in mines to a certain extent.

Abstract:Among China’s mineral resources, coal mine is the main mineral resource. If coal mine can be mined intelligently, the efficiency of China’s mineral resources development will be greatly improved, which will directly accelerate the intelligent development of society and the promotion of national economy. Through years of development, the mechanization level of intelligent coal mining in China has gradually improved and moved towards intelligence. By the end of 2019, there were more than 200 intelligent mining faces in China, and the intelligent coal mining with less people is gradually developed. However, the current mining technology still does not reach the expected level in the operation application. From a macro point of view, the intelligence level of some coal mining is relatively primitive. If fully and truly intelligent mining is aimed, the corresponding development and efforts are still needed.

Abstract:This paper mainly analyzes the objectives and the key problems in the governance process of uranium geological exploration facilities decommissioning, and puts forward five governance schemes. It also predicts and evaluates the governance effect, and continuously monitors and controls the decommissioning and governance, which provides reference value for decommissioning of uranium geological exploration facilities.

Abstract:Applied as an advanced approach to control the noxious gas, like gas, pressure balanced ventilation technology was widely popularized in the 1990s. However, the adverse effects can not be neglected, because once the booster fans are powered off or malfunctioning, the concentration of the noxious gas in certain work-face would be raised up immediately and over the limit of gas in a short time. Through conscious analysis of the origin of gas and the air distribution of certain work-face, Xinzhou coal mine applied several effective approaches to solve the problem of controlling the noxious gas under the condition of none pressure balance ventilation. The approaches are as follows: full negative pressure drainage through the main mine fans; sealing off the opposite end and tail end of air bag; introducing the compressed air ejector; releasing the noxious gas in the nearby mined-out area by connecting the emission pipelines with the measure holes, observation holes, and drainage holes in nearby mined-out area and constructing actively the gas drainage system.