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By D. R. Hanson, H. Lawson

In this study, NIOSH researchers conducted a machine learning analysis to examine whether a model could be constructed to assess the probability of dynamic failure occurrence based on geochemical and petrographic data. Random forest, cluster analysis and dimension reduction were all applied. The objective of dimensionality reduction was to explore patterns and groupings in the data and search for relations between compositional parameters. Cluster analyses were performed to determine if an algorithm could find clusters with given class memberships and to what extent misclassifications of dynamic failure status occurred. A random forest analysis performed on data from the Pennsylvania Coal Sample Databank cross-referenced with accident data from the Mine Safety and Health Administration (MSHA) determined that 7 parameters of the 18 examined exerted the most influence on results. Cluster analysis on data after dimensionality reduction resulted in a hierarchal clustering algorithm finding four clusters, with one relatively distinct dynamic failure cluster, and three clusters consisting mostly of control group members but with a small number of dynamic failure members.

Feb 1, 2023

By . A. Drouin, J. -M. Lalancette, D. Lemieux, C. Chouinard

"A gold bearing pyrite concentrate was treated at the demonstration scale (15 t/d) for the extraction of gold using a cyanide-free process. The pyrite was depressed in the flotation circuit in order to promote the flotation of copper and to achieve a sufficient copper grade to meet the copper smelter criteria. However, the recoveries of copper were 80% and only about 50% for the gold was found in the copper concentrate. The balance of the gold (50%) and copper (20%) contained in the pyrite concentrate as a reject from an overall flotation circuit. The gold grade in the pyrite concentrate is 5.40 g Au/t and copper about 0.77%. About 170 tons of pyrite concentrate were processed in the DST demonstration plant. The concentrate was first oxidized using a fluid bed to produce a calcine. Copper was then extracted as copper sulphate using diluted sulphuric acid. The residual solid was submitted to the DST chlorination process for gold extraction. Thereafter, the gold was recovered from the pregnant brine by precipitation over silica using DST proprietary process. The maximum gold recovery by chlorination was 90%. The average gold recovery by cyanidation of these calcines was 71%. INTRODUCTION Dundee Sustainable Technologies (“DST”) has developed a chlorination process as an alternative to the conventional cyanidation process for the extraction of precious metals from ores or concentrates. The technology offers viable and efficient gold recoveries and the ability to handle refractory ores and contaminated material (As, Hg, etc..). The process was successfully demonstrated on hundreds of samples provided by various mines, exploration and development projects and has evolved from laboratory experiment to demonstration at an industrial scale. DST’s chlorination process operates in a closed loop circuit, which implies that no liquid effluents are generated. The chemistry and process design allows precious metal deposits containing base metals to be treated viably. The tailings from the process are inert and non-toxic, sulphide depleted and thus non-acid generating. The efficiency of the process has demonstrated excellent gold recoveries within a fraction of the time needed for cyanidation to obtain similar results. The company completed in 2015 the construction of the first industrial demonstration plant operating with the DST technology. The plant has a capacity of 15 tons per day of mineral concentrate, and the ability to extract gold and silver utilizing DST chlorination technology. DST has tested its chlorination technology at demonstration scale on the refractory pyrite concentrate containing 5.40 g Au/t and 0.8 %copper. This auriferous pyrite concentrate, was by-product of copper concentrate respecting the copper smelter norms, is produced in a country where cyanide is prohibited and refractory to cyanidation. The pyrite concentrate was initially processed successfully (gold recoveries: > 90%) by the DST technology at laboratory (2011: 20 kg) and pilot (2014: 5 tons) scales to extract gold. About 170 tons of this pyrite concentrate were processed in the DST demonstration plant located in Thetford Mines."

Jan 1, 2017

By M. Zaske, E. R. Mortensen

"As mine operators continuously look for ways to improve functionality and increase capacity of their facilities, existing process equipment is often pushed to and past its designed limitations. As a result, equipment manufacturers are asked for economical solutions to meet redefined processing needs. Newmont USA (Newmont) in Nevada was faced with such a need in their Carbon-in-Leach (CIL) train. In a collaborative effort between Newmont and Derrick Corporation, tests were conceived to assess the viability of drop in replacement screen using a three dimensional screen panel. The urethane pyramid screen panel was designed to increase flux while maintaining the existing equipment footprint. The test is the end result of an ongoing research and development project that Derrick undertook in an effort to refine and upgrade their urethane screening media. The application of this new screening media is presented for this CIL application along with future plans to implement the technology in trash, safety, carbon dewatering, carbon sizing, and other scalping applications.INTRODUCTION In Spring of 2014, Process Machinery Associates (PMA), Derrick Corporation’s (Derrick) local area representative, met with Newmont USA (Newmont) to discuss the operation of the in tank screens in the carbon in leach (CIL) train at Twin Creeks, near Golconda, Nevada. The process was originally designed for 13,000 +tons per day (tpd) but has been steadily rising since the plant was commissioned and now Newmont requires 16,000 tpd to be processed. The original screens were running at their maximum capacity and Newmont required additional screening capacity to continue the upward trend in production. Physical separation by use of screening is one of mineral processing oldest methods. Screening media can be prone to blinding and pegging and the necessary support structures required for finer apertures result in smaller open areas. Therefore, more screening area generally requires larger panels and therefore larger machines, screening media that doesn’t blind, or a combination of both. In an effort to avoid larger machines, Derrick Corporation had been working on a revolutionary three dimensional panel which would add non blinding screen area in the same footprint of an existing machine. Alpha testing of the new screen panels began at Newmont Mill 2/5 (Carlin, Nevada) in July of 2013 and was still occurring when PMA approached Twin Creeks about beta testing a refined machine and pyramid panel. After presenting the initial results, Twin Creeks determined that an upgraded machine and pyramid panels would be a possible solution to meet production needs. The testing of a machine eliminated the risk of capital costs to Newmont and provided Derrick the opportunity to obtain additional data."

Jan 1, 2015

By Norbert Patzelt, Johann Knecht

INTRODUCTION Grinding mills have been used in the minerals processing industry for over 100 years. Their dimensions have grown continuously during this time. Besides increasing throughput rates of grinding plants due to the depletion of high grade ores, the lower specific in- vestment costs, as well as reduced operating and maintenance requirements are major reasons for this trend. When selecting new plant equipment one must consider that design principles which have proven their reliability on sizes of today's equipment do not automatically warrant a successful operation on the ever larger size of equipment. Modern calculation methods as for instance the Finite Element method already contribute considerably to the safe design of the huge equipment being built today and are a standard tool of the design engineers. More recently, modern computer programs are also being used in order to size the equipment to meet the process requirements. Today, two design principles are on the market - one which supports the weight of such a unit on trunnion bearings through cast conical endwalls and one which is supported through slipper pad bearings arranged at the circumference of the mill shell (Fig.1). The reason for the development of this alternative grinding mill design can be found in the past. During the sixties and seventies the growing sizes of ball mills with high LID ratios caused many mill failures due to cracked endwalls. The accuracy of the calculation methods as well as the quality standards for castings were not developed to a degree required for such kind of heavy equipment. One way to overcome these problems was the increase of the manufacturing quality standards as well as the introduction of the finite element method based on the analysis of the experience available. The biggest grinding mills being built today are large size SAG mills with cast conical endwalls and trunnion bearings (Fig.2). This is due to the fact that mill manufacturers who had come from the conventional ball mill design adopted these principles as well to their SAG mills. These grinding mills perform well without special concern to the operators. Other manufacturers overcame the problems as mentioned above by eliminating completely the heavy castings and trunnion bearings and the problems associated to it (Fig.1). This design was originally applied to ball mills for the mining and other industries. Due to the success of these shell supported ball mills, this design principle was also applied to SAG mills(Fig.3). Despite of the fact that the majority of today's grinding mills are built to the conventional design it is also interesting to have a look at this alternative. Principles which have proven their reliability on sizes of today's equipment do not automatically warrant a successful operation on the ever larger equipment if bigger mill sizes are realized only based on the pantograph principle. With growing grinding mill sizes, the mass and volume flows through the equipment increases rapidly. Thus it is very important not only to concentrate on the safe design of the structural components of the equipment but as well on the process requirements. The influence of the design on important process parameters of dry and wet grinding plants are discussed thereafter. It shall be shown how modern computer programs can assist in the optimization of the design of components in order to fulfil the operational requirements of such large size equipment. PROCESS REQUIREMENTS OF LARGE SIZE GRINDING MILLS Dry Grinding Mills The world's biggest ball mill is a dry grinding ball mill having a diameter of 6.2m and an overall length of 25,5m with a drive power of 11,200 KW or 15,000HP. This grinding mill dries and grinds gold ore at a rate of 500 tons per hour at a moisture content of up to 9,5%. As shown in Fig.4 this mill was built as a shell supported unit. In fact only this design principle allowed to meet the process requirement. This mill could hardly be built with cast conical endwalls due to the constraints of the trunnion bearings limiting the mill inlet. The following case shows how modern computer programs can help to meet the design criteria of the air system of large size dry grinding plants. For dry grinding plants, the gas flow through the SAG mill has to match the drying, as well as the material transportation require-

Jan 1, 1998

By J. Bilant, B. Carlson, N. Gow

"High-pressure grinding roll (HPGR) technology was evaluated to replace tertiary cone crushing at Coeur Rochester operations (Coeur Rochester Inc.) as an opportunity to improve silver recovery. In 2016 and 2017, onsite and third-party pilot programs were initiated to evaluate the impact on metallurgical recovery and heap leach performance of crushed product generated by an HPGR. In 2018, Forte Dynamics evaluated the HPGR laboratory metallurgical data from Coeur Rochester and all third parties to develop field-scale leach curves based on new crushing scenarios. The laboratory recovery test work data were consolidated and scaled to field conditions to determine projected heap leach performance. Based on the metallurgical testing conducted, the replacement of current tertiary cone crushers with HPGR technology has the potential to increase Coeur Rochester’s silver recovery rate by 8 percentage points, from 61 percent to 69 percent, and shorten the overall timing of silver recoveries from 20 years to just more than two years.The Rochester Mine, and associated valley fill heap leach facilities is an openpit silver and gold mine located in Pershing County, NV, approximately 42 km (26 miles) northeast of the city of Lovelock. In 2017, Rochester produced approximately 4.7 million oz silver (Ag) and 51,000 troy oz gold (Au). Ore mined at Rochester is either fed directly to the primary X-Pit crusher, crushed at an in-pit crusher system, or placed directly onto a heap leach pad as run-of-mine (ROM). Both crushing circuits are comprised of three stages of crushing to produce a nominal 3/8 in. ore. Primary crushing consists of jaw crushing while secondary and tertiary crushing are composed of varying cone crushers.Historical recovery rates of crushed Rochester ore averaged 61.4 percent Ag and 95.9 percent Au over a period of 20 years (Robinson et al., 2018). These rates were derived from third-party verification of in-house metallurgical test results, crusher production and heap leach production results from 1986 through 2004 in a private report for Rochester produced by KD Engineering Co., Inc. Recovery rates are regularly verified by compositing daily samples of ore delivered to each leach pad from the X-pit crusher, in-pit crusher and/ or ROM. A proportionate split of each sample is used to generate monthly composites for metallurgical analysis utilizing column leaching and bottle roll leaching. These tests are run in a manner analogous with production conditions and deliver test results that provide expected heap leach performance. As the Rochester oxide deposit has been mineralogically and metallurgically consistent, the gold and silver recovery trends have also been consistent over the life of the project."

Sep 1, 2019

By J. A. Organiscak

The National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) has recently studied several redirected scrubber discharge configurations in its full-scale continuous miner gallery for both dust and gas control when using an exhaust face ventilation system. Dust and gas measurements around the continuous mining machine in the laboratory showed that the conventional scrubber discharge directed outby the face with a 12.2-m (40-ft) exhaust curtain setback appeared to be one of the better configurations for controlling both dust and gas. Redirecting all the air towards the face equally up both sides of the machine increased both the dust and gas concentrations around the machine. When all the air was redirected towards the face on the off-curtain side of the machine, gas accumulations tended to be reduced at the face at the expense of increased dust levels in the return and on the curtain side of the mining machine. A 6.1-m (20-ft) exhaust curtain setback without the scrubber operating resulted in the lowest dust levels around the continuous mining machine, but this configuration resulted in some of the highest levels of dust in the return and gas on the off-curtain side of the mining face. Two field studies showed some similarities to the laboratory findings, with elevated dust levels at the rear corners of the continuous miner when all the scrubber exhaust was redirected towards the face either up the off-tubing side or equally up both sides of the mining machine.

Feb 23, 2014

By H. B. Miller

By its nature, underground metal mining is unlike any other business in the industrial sector. Operations are continuously exposed to economic risk as a normal consequence of mining due to uncertainties associated with the? deposit, excavation, and ever changing political, regulatory, and market conditions. Out pacing advances in productivity and technology, these conditions have contributed to the steady decline of underground hardrock mining in the United States. This paper investigates the trends and major factors believed to be responsible for this decline. Special consideration is given to changes in direct operating costs, labor productivity, and production capacity.

Jan 1, 1995

By J. Noll, C. DeGennaro, C. Zhou, J. Srednicki

"The personal dust monitor (PDM) (model PDM3700), as well as other electronic devices, can cause electromagnetic interference (EMI) which can disrupt the operation of some proximity detection systems (PDSs). A 15 cm (6 inch) minimum separation distance between the miner-wearable component (MWC) of the PDS and the electronic device usually avoids these disruptions, but due to the amount of equipment on a miner’s belt and the method of wearing the PDM in some situations, this distance can be difficult to always reliably maintain. Another method of reducing EMI effects is utilizing magnetic field shielding. The shielding capability of several different materials was investigated by surrounding the PDM with the material and quantifying the EMI. A copper mesh pouch reduced the EMI from a PDM3700, allowing a minimum separation distance of 10 cm (4 inches) instead of 15 cm (6 inches) as shown in a previous study for an unshielded PDM. A MU-metal box had a better shielding effectiveness, as it further reduced the minimum separation distance to less than 7 cm (2.8 inches). Shielding reduced the EMI of the PDM with MU-metal providing better results than the copper mesh. These materials may be beneficial for shielding individual components of the PDM or for constructing a shielded pouch. However, before the advantages of a shielded pouch can be determined, the effects of just the shielding material (metal) on the PDS needs to be quantified. INTRODUCTION According to statistics from the Mine Safety and Health Administration (MSHA), 43 miners have been fatally struck or pinned by a continuous mining machine (CMM) since 1984. In an effort to prevent future striking and pinning fatalities from occurring, proximity detection systems (PDSs) have been developed and are required on all operating CMMs in underground coal mines, with the exception of full-face CMMs, by 2018 (MSHA, 2015)."

Jan 1, 2018

By Mark J. Zdunczyk

"The term “aggregate” has a number of definitions depending primarily on the use of the material. Aggregate in some context is sand, gravel, crushed stone, slag or other material of mineral composition used in bituminous and portland cement concrete, mortar, plaster, railroad ballast, filter beds and a variety of other uses where aggregates can be utilized.Of the natural aggregates, crushed stone is widely used for most construction purposes. Crushed stone can be mined from a variety of rock types such as limestone, dolomite (dolostone), granites, and granitic type rocks, basalt, gabbro (trap rock), sandstones, schist, marble, gneiss, quartzite, rhyolite, as well as other rock types. The U.S. Geological Survey (USGS) breaks down the rocks by type sold as follows: limestone, dolomite, marble, calcareous marl, shell, granite, trap rock (basalt, diorite) sandstone/quartzite, slate, volcanic cinder and scoria and miscellaneous stone.In 2015, the USGS estimates that 1.32 Gt (1.45 billion st) of crushed stone were produced in the United States. The volume of crushed stone produced, and the numerous mines that produce it make the crushed stone industry the largest mining industry in the United States. The five leading states for production of crushed stone in 2015 were Texas, Pennsylvania, Missouri, Florida and Ohio. The size of the first two states certainly helps in output because of the large market area. The remaining states benefit from being able to barge along rivers to outside markets in adjoining states. Georgia producers rail large amounts of granitic aggregate to Florida and adjacent states devoid of crushed stone aggregate, especially skid resistant aggregate (aggregate used on the top course of asphalt roads)."

Jul 1, 2016

By Gerhardt A. Bennewitz

The mechanism shown here (Fig. 1) may not be all that it appears to be. To many of you it may look like a hopper car, a thing of mobility, in which you would ship coal, ores, limestone, or other bulk materials. It is approximately 50 feet long, 12 feet high, and can be placed on tracks which are on approximate 14 foot centers. But far too often in the past, and all too often today, this mechanism has been made to serve as an immobile storage box, with its primary role -- the transportation of products, seemingly incidental to the storage function. Our engineering training teaches us to conserve resources, despite some of the popular and misconceived philosophies being advanced these days. Those of you who work for companies with traffic departments know that they are always striving to reduce the price which is paid to move your mine products. Today, let's consider and analyze the ways in which the cost of transporting your mine products might be reduced, based on particular reference to coal. Bear in mind that in this context, cost and price are not necessarily synonymous. Until a few years ago, most coal and other bulk materials handled by railroads moved under standard tariff rules. These rules, which still exist today, provided transportation vehicles (railroad cars) for extended periods at no added price to the shipper or receiver. "Normal" free time rules would permit a car to be held for a maximum of 48 hours without charge; however, in the case of coal, there is a rule which, subject to liberal rules as to the

Jan 1, 1972

By R. Riding

Degussa Corporation's peroxide-assisted leaching (PAL) process was evaluated in the batch concentrate leach circuit at Hecla Mining Company's Republic Unit. The product leached in this batch circuit is a high grade gold-silver sulfide (predominately pyrite) flotation concentrate. The primary objectives of the test program were to determine the effects of dilute hydrogen peroxide addition on leaching kinetics, sodium cyanide consumption and precious metals recovery. The results of the testing demonstrated that using dilute hydrogen peroxide produced the following benefits: - 1. Batch leach time requirements decreased by 80%. - 2. Sodium cyanide consumption in concentrate leach reduced by 55%, which translated to an overall plant reduction of 20%. - 3. In the concentrate leach process, gold recovery was increased by 1 to 2%. Because of the excellent metallurgical results achieved with the use of dilute hydrogen peroxide, as well as an economic incentive, PAL has become standard practice in the concentrate leach circuit operation. A complete description of the Republic PAL plant evaluation and performance is provided in this paper. In addition, process chemistry considerations in regard to the role of hydrogen peroxide are discussed.

Jan 1, 1992

By Lawrence D. Ramspott

A test of retrievable geologic storage of spent fuel assemblies from an operating commercial nuclear reactor is underway at the Nevada Test Site (NTS) of the U.S. Department of Energy his generic test is located 420 m below the surface in the Climax granitic stock. Eleven canisters of spent fuel approximately 2.5 years out of reactor core (about 1.6 kW/canister thermal output) were emplaced in a storage drift along with 6 electrical simulator canisters. Two adjacent drifts contain electrical heaters, which are operated to simulate within the test array the thermal field of a large repository. Fuel was loaded during April-May 1980 and initial results of the test will be presented.

Jan 1, 1981

By Andrew J. Petruska, Rik Banerjee

This study explores implementing a machine learningbased system to generate a 3D surface repre- sentation of the roof and support straps in the mine. Event cameras have been chosen for their performance in high-dynamic-range lighting conditions and for their low latency. To enable automated drilling and bolting, 3D vision using eventbased cameras has been developed. A ground-truth set is created using two, time-synced event cameras and a LiDAR camera. These sensors are used to construct a ground-truth dataset of corresponding event- camera images and surface maps from the LiDAR. The network is tested with stereopairs of event images and produces a depth image with ±5 mm RMS error on average across 1000 test images.

Feb 1, 2024

By Derek Brennan, Donald Brennan

"The existing Rondout West Branch Tunnel (RWBT) is part of the Delaware Aqueduct which has been in service since 1944 and accounts for more than 50 percent of New York City’s water supply. In early 2015, the New York City Department of Environmental Protection contracted Kiewit-Shea Constructors, AJV (KSC) to construct the Rondout West Branch Bypass Tunnel project (Rondout) in order to mitigate the leakage of 132 million L/ day (35 million gpd) of water from two areas of the existing tunnel; the Roseton and Wawarsing areas.The scope of the Bypass Tunnel 2 project is separated into two distinct phases. Phase 1 consists of completing the shaft sinking to a depth of approximately 274 m (900 ft) at shaft 5B, 213 m (700 ft) at shaft 6B and the excavation of approximately 3,850 m (12,500 linear ft) of tunnel at a diameter of 6.6 m (21 ft 7 in). This phase also includes the installation of 2,804 m (9,200 linear ft) of 4.8 m (16 ft) diameter steel interliner pipe through the new bypass tunnel with cast-in–place concrete liner for a finished diameter of 4.2 m (14 ft). Access chambers at the top of shafts 5B and 6B will be constructed for access and housing of the mechanical and electrical equipment for supporting pumps and valves.Included in phase 2 is the additional excavation from shafts 5B and 6B to the RWBT, and the drainage tunnel to remove ground water infiltration from RWBT. This work will be completed during a scheduled shutdown of the RWBT and will include approximately 31 m (100 ft) of excavation of the two connection tunnels. Additionally, construction of the permanent plugs within the RWBT will be undertaken. Figure 2 shows the layout of the work.Access to the work through the deep shaft at site 5B was critical to the success of the project. The hoisting system needed to be multi-functional to handle the different types of construction from drill and shoot of the shaft, starter and tail tunnel, the assembly of the tunnel boring machine (TBM), the excavation of the TBM tunnel including the supply of the precast segmental liner, the grouting operations, the installation of the steel interliner pipe and the cast-in-place concrete as well as ingress and egress of personnel. The production of the TBM operations was critical to the schedule of the project. This required a quick cycle for muck haulage and supply of the precast segmental liner in order to keep pace with the excavation time of the TBM. For TBM assembly, components were limited to a maximum weight of 104 t (115 st) for a single lift. Various cranes were analyzed for hoisting, however, none would meet all of the citeria. Therefore, the project team selected a specialized hoisting system designed in house in conjunction with Timberland Equipment Ltd. that consisted of a total of 14 separate hoists and winches with a total of more than 2,833 kW (3,800 hp)."

Mar 1, 2019

By Meili Zhu, Qingpu Shi

High temperature, methane, dust and other disasters are getting more serious with mining depth getting deeper and the development of mechanization in underground mines. An application of a descensional ventilation to a coalface is one of the effective measures to solve the above problemes. The descensional ventilation is an venttilation that an airflow in a coalface wouuld downflow along an inclination of a coalface and the direction of the airflow is the same as coalflow. Since 1960's, the descensional ventilation has been applied to 171 coalfaces in 46 coal mines of 23 coal mine administrations in China, such as Pingdingshan , Zhongliangshan, Pubai, Huangshi coal mine administrations. Among the 171 coalfaces, there were 104 coalfaces taking 60.8% in gently inclined seam. The coalfaces in inclined seam and steep seam were individually taking 18.7 % and 20.5 %. There were 77 coalfaces taking 45 % of the total in low gassy coal mines and coal and methane outburst mine were individually taking 17% and 38%. There were 141 coalfaces taking 82.5% of the total in potential danger of dust explosion. There were 125 coalfaces taking 73.1% of the total in potential danger of spontaneous combustion. Therefore, the descensional ventilation can be used in coalfaces under different conditions in China. The practice at home and abroad shown that the application of the descensional ventilation to coalfaces has obvious results in dust control, temperature control, preventing methane accumulation at top corner angle and control of spontaneous combustion in goaf. To more safely and reliably apply the descensional ventilation to coalface and to provide a way for the development of mine ventilation technology in China, the paper will have discussions on the following problems: METHANE EMISSION AND DISTRIBUTION AT COALFACE WITH DESCENSIONAL VENTILATION Methane emission in a coalface with a descensional ventilation is an argued issue for many years. Base on the coal practice, special similar model tests and researches in China, the followings are our main comments. The Descensional Ventilation can Reduce the Methane, Accumulation at the Top Corner Angle. The measurements in six coalfaces with the downward airflow in Qinhemen Mine, Fuxin Coal Mine Administrations shown that the methane concentration at the top corner angle is often up to l% when the coalface has the upward, airflow. The max. methane concentration at the top corner angle is about 0.49 to 0.7% when the coalface has the descensional ventilation. Therefore, with the descensional ventilation, it basically solved the overlimited gas concentration at the top corner angle which is a potential danger to coal production. Because the direction of upfloating gas is opposite to the direction, of the descensional airflow, the descensional ventilation; could increase a turbulent flow mixing capacity of the methan gas and air, and reduce a possibility of methane; accumulation. Due to an air leakage in goat when the coalface with the descensional ventilation lower than an air leakage in goat when the coalface with the, ascensional ventilation, a less methane quantity will release from goat at the descensional ventialtion. It should be pointed out that due to a higher air leakage at ascensional ventilation and the direction of the air; leakage same to the direction of the natural upfloating methane in goaf, those will cause a large methane; accumulation at the top of the goaf and easy bring about, methane accumulation and overlimited methane concentration at the top corner angle with an ventilation vortexflow at the top corner angle. On the other hand, because the direction of the upfloation force function is upward, the descentional ventilation could minimize as possibility of methane accumulation at top corner angle in coal with the descensional ventiltion.

Jan 1, 1991

By G. C. Kachel

Significant effort has been expended and considerable success has been realized m the application of instrumentation and automatic control equipment in the mining and ore processing industries. This effort has been applied principally to process equipment with the objective of increasing throughput, minimizing labor requirements and/or improving grade or product quality. Less spectacular, but quite rewarding has been the successful application of instrumentation and automatic control equipment to a wide variety of material handling equipments. This paper describes some of this work including: (1) automatic weighment of load-haul-dump units and trams underground; (2) automation of skip loading; (3) instrumentation applied in feeders and conveyors; (4) level measurement in bins, silos, vessels and sumps; (5) automatic blending of sized materials; (6) automatic loading of ships, trains and trucks; (7) automatic control of tailings disposal facilities

Jan 1, 1973

By Ji Fang, Chong Fan, Fengrui Wang, Dongxin Bai

Unmanned mining technology in underground mines offers high efficiency, safety, and low cost. However, ground operators face challenges in accurately perceiving the underground environment through videos. This paper presents an augmented reality (AR) platform developed to enhance the unmanned mining process. The platform uses cameras and 5G technology to transmit high-fidelity video streams to the ground, where key targets are identified and virtual models are registered in the video to enhance the real scene. Tests in the Xinli stope of the Sanshandao gold mine showed the platform’s effectiveness in improving ground operators’ perception and production efficiency.

Jan 30, 2022

By İlknur Erol

The abstract highlights that hearing loss is an occupational disease caused by noise exposure in the workplace. The study investigates noise-induced hearing loss among miners in underground coal mines in Turkey, considering factors like occupation, age, and exposure time. The research employs logistic regression analysis to reveal the relationship between hearing loss and these factors. The findings suggest that occupational groups and duration of noise exposure significantly affect hearing loss. Miners in production groups and those exposed to noise for 10-14 years have a higher risk. The study concludes that age does not significantly increase the probability of hearing loss.

Mar 24, 2022

By E. L. Gillenwater

Coal mine planning has three distinct decision levels: (1) decisions made at the upper level of management that determine production requirements for specific mines, (2) decisions made at the middle management level, the mine level, that determine how the mine satisfies its production requirements, and (3) decisions made at the operating level of management, the sectional level, that determine the sequencing of machine movements at the face. In this paper, the underground production scheduling problem is formulated in multi-stages using the Hierarchical Production Planning (HPP) approach. Two linear programming HPP models for accomplishing decisions at the first two levels are developed. Both models address the aggregate production planning process. The Mine Production Scheduling (MPS) model permits determination of monthly production and inventory levels. The Section Production Scheduling (SPS) model incorporates a quality blending requirement into the determination of weekly sectional production and inventory levels.

Jan 1, 1995

By K. T. Stafford, N. A. Iverson, V. T. McLemore

Southwestern New Mexico is part of a large belt of Late Cretaceous to Eocene copper porphyry deposits found in Arizona, New Mexico, and Mexico. These deposits are the result of arc magmatism that occurred during the Laramide orogeny. Recently, attention has been brought to other commodities that can be extracted as by- and co-products, many of which are critical minerals. A new compilation of the geochronology of these deposits shows two main pulses of magmatism that produced mineralized deposits and, along with new dates by the author, shines new light on the geologic history of these deposits and the role it plays in critical mineral abundance.

Feb 1, 2024