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By P. Zhang

The Crago “Double Float” process is widely used in upgrading phosphate ore. This process is inefficient, as it floats about 30-40% of the sands in the flotation feed twice and requires a deoiling step. This paper summarizes several research projects on improving phosphate flotation. The University of Utah investigated a new flotation chemistry for efficient flotation of phosphate in a single step. The Florida Institute of Phosphate Research developed several single-collector, all-anionic flotation flowsheets using various sizing schemes. In addition, Eriez invented the HydroFloat separator, which demonstrated great potential for processing coarse flotation feed in one step.

Jan 1, 2004

By Mahmud Esad Uluer, Seyed Hassan Amini, Aaron Noble, Matt Shigo

Airborne coal mine dust is an unintended and unavoidable result of coal extraction operations that raises notable health and safety concerns. Modern mining techniques utilize several dust mitigation strategies, and the flooded-bed dust scrubber (FBS) is one such technology used extensively on continuous miners. The conventional static panel filter, instrumental in most scrubber designs, is fundamentally limited in collection efficiencies due to a high clogging rate and a tradeoff between mesh density and airflow rate. To overcome these deficiencies, a novel vibrating mesh panel is proposed. In this study, a laboratory-scale dust scrubber unit was used to investigate the efficacy of concept as compared to that of a static mesh. A statistical design of experiments study was first used to determine the effective vibrational parameters and scrubber operational parameters on dust collection and clogging mitigation. Optimized results from this study were then evaluated against those of a static mesh to determine performance improvement while investigating the mechanisms controlling dust collection and particle department through the scrubber system. Results show that the vibrating mesh conditions and higher water flow rates led to an improvement in the collection efficiency of the scrubber system. Compares to a static-mesh, the vibrating mesh FBS showed a significant reduction in pressure drop across the mesh screen indicating lower air loss through the test duration. Overall, the findings confirm that vibrating filter mesh reduces filter clogging while maintaining high collection efficiencies. This research supports further technological advancement in mine dust mitigation technologies.

Dec 27, 2023

By Adabala Raja Venkata Sai Naresh, Radhakanta Koner

Particle size distribution (PSD) is an essential parameter in assessing the overall efficiency of blasting operations in mines and the subsequent mine-to-mill process in the mining industry. Despite some drawbacks of 2D image analysis techniques in accurately estimating particle sizes in PSD, the mining industry has relied on them for the last three decades. This study proposes the 3D rock fragmentation measurement (3DFM) technique for deducting the accurate dimensions of 3D rock particles for the PSD. 3DFM has utilized different processing algorithms. Images of different views of the non-touching rock particles of varying sizes have been acquired as a data acquisition step of structure from motion technology for generating sparse point cloud. Dense point cloud reconstruction is used to avail finer details of the point cloud using clustering views for the multi-view stereo algorithm. Random sample consensus (RANSAC) algorithm coupled with an unsupervised classification using the density-based spatial clustering of applications with noise (DBSCAN) classifier is employed to extract the rock clusters from the 3D point cloud. Finally, the accurate rock sizes are derived using the hybrid bounding box rotation identification (HYBBRID) algorithm with a root mean square error (RMSE) of 0.10 cm for length, 0.10 cm for breadth, and 0.32 cm for depth. The PSD of rock fragments obtained from the proposed 3DFM technique is found to be matching with the results of mechanical sieving and manual gauging with an R2 values of 0.98 and 0.99, respectively. The 3DFM method can be considered cheaper, more accurate, and computationally faster in determining the rock dimensions for the PSD determination method to enhance the productivity of the mining industry.

Dec 29, 2023

By Shaoxian Song, Ling Xia, Hongqiang Li, Yubiao Li, Yunliang Zhao, Shaobing Xie

Since human daily demands for fresh water have been increased significantly, the supply of fresh water for the mining industry, especially froth flotation, should be considerably reduced. In addition, stricter environmental standards have been implemented in many countries to reduce the risks due to the disposal of wastewater, many flotation operators have to seek more efficient ways to utilize the limited fresh water sources. Recycling water with high concentrations of impurities is a normal strategy for most of the mineral processing plants; however, water quality should be carefully considered to guarantee a smooth flotation process. Recently, the application of seawater in flotation has attracted much attention due to its availability and abundance rather than fresh water. However, the influencing mechanisms due to the application of seawater in flotation have not been fully understood especially the reactions between mineral particles and bubbles in the presence of high concentrations of cations and anions. This would impede the application of alternatives to fresh water in the flotation. Therefore, this paper reviews the current water sources and the technologies for water recycling in the flotation process. Specifically, the life cycle of water in flotation was proposed. In addition, the strategies including high pulp density flotation as well as the most promising alternatives to fresh water have been discussed in details, with the related mechanisms being demonstrated.

By Lauro Lacerda

Shotcrete is a highly adaptable and widely used underground construction material at infrastructure and mining projects around the world. In fact, many projects could not have been completed without its utilization. As underground projects became larger the use of mechanized wet-mix spraying gradually replaced manual dry-mix shotcrete applications. This paper details some of the reasons for that and provides information on the equipment and operational factors including safety and productivity required to successfully complete underground shotcrete projects.

Jun 13, 2021

By James P. Connell

The American Concrete Institute defines "shotcrete" as "mortar or concrete conveyed through a hose and pneumatically projected at high velocity unto a surface." This definition thus includes what is traditionally known as "gunite," which is a pneumatically applied mortar. In mining practice, the term shotcrete is restricted to pneumatically applied concrete, and this differentiation will be used in this paper. In 1914, following the invention of the mortar gun in 1907, the then Chief Engineer of the U.S. Bureau of Mines, George Rice, developed the guntie process for underground test work at the bureau facility at Bruceton, Pennsylvania. After World War I, gunite was used extensively in American mines and was also utilized for underground civil works such as the San Jacinto Tunnel in California. The greatest development was In Europe where, as early as 1911, gunite was successfully used as an overlay for deteriorated tunnel linings. In 1951, the Swiss firm Aliva developed a pneumatic gun capable of handling coarse aggregate, thus making possible the first use of shotcrete at the Maggia hydropower development. Intially, shotcrete was used to reduce manpower requirements for forming; and placing conventional concrete. However, by 1954 Sonderegger was reporting that the structural advantages of shotcrete were derived from its flexibility and from the fact that it could be applied almost immediately niter the opening had been made. The incorporation of wire mesh into the shotcrete led to the New Austrian Tunnel Method, or NATM. The use of shotcrete in American mines has been implemented more recently. This delay seems to be due to previously unsuccessful experiences with gunite as a structural material and to the U.S. reliance on wood or steel supports in main line haulageways. The long experience with the apparently more substantial rigid supports led mine operators to be reluctant to the new and seemingly unrealistic lighter shotcrete support.

Jan 1, 1977

By Arthur B. Johnson

Potassium, is one of the three basic plant nutrients along with nitrogen and phosphorus. There is no substitute for potassium compounds in agriculture; they are essential to maintain and expand food production. Potash is found throughout the world in both soluble and insoluble forms. It is only the soluble forms that are economically attractive to process, primarily chlorides and sulfates, with potassium chloride by far the most important potash salt. Sylvinite ore, a mechanical mixture of sylvite (KCl) and halite (NaCl), is a natural mineral of potassium. This ore is found in commercial quantities in the Permian sin region near Carlsbad, New Mexico. Vast tonnages of high-grade de, low-clay-content ores have been mined and concentrated during the past 40 years; however, these deposits are rapidly being depleted leaving high-clay, low-grade ore reserves of over 135 million tons. These ores, containing 13 to 22 percent K20 and 3 to 8 percent clay slimes; cannot be effectively processed by current commercial flotation methods. The present concentration processes for potash minerals in Carlsbad relate mainly to ores containing 1 percent or less of clay-slimes with a K20 content of 20 to 25 percent to yield products to meet the requirements of the agriculture market, namely, 95 percent KC1 equivalent to 60 percent K20. Discoveries of potash ore in Saskatchewan, Canada, have shifted the emphasis on expansion outside the United States. Presently, the American companies are looking to Canada for future growth, expenditures, and expansion. Four of the seven companies operating near Carlsbad are produces of Canadian potash despite the large investment sons required for shaft sinking and milling installations.

Jan 1, 1970

By Colleen A. M. Gibbs

On July 30, 1979 New Council on Environmental Quality (CEQ) regulations for implementing the procedural provisions of the decade-old National Environmental Policy Act went into effect. These new regulations replace approximately seventy different sets of agency regulations, providing some uniformity throughout the Federal government in the conduct of environmental reviews and preparation of environmental impact statements (EIS). This attempt by the Federal government at a general improvement in the preparation and quality of EIS's presents an opportunity for the mining industry to evaluate how the EIS process for mining proposals can be expedited. The environmental impact statement is often a key element on the critical path of a major mining project. Preparation of the EIS is ordinarily the responsibility of the Federal agency with primary decision-making authority over the project. Still, the proponent, i.e. the mining company, can play a major role in the process and have a major impact on the timeliness and adequacy of the effort. Typically, the Proponent will conduct (or will hire consultants to conduct) environmental baseline studies of, for example, air quality, wildlife, geology, water quality, vegetation and archaeology. These studies are then compiled into an environmental report and submitted to the agency. The agency verifies the data and incorporates them into the environmental impact statement.

Jan 1, 1979

By Simon Wright, Roland Heersink

In the past, the center of most companies' e-initiatives has been on reduction of indirect costs, such as selling and procurement. Recently, e-commerce has moved its attention from back-office functions into manufacturing, in order to significantly reduce direct operating costs. This paper describes many of the Web-Powered Manufacturing initiatives being employed across various industries, and relates them to similar opportunities being started within the mining and mineral-processing sector. The following opportunities are enabled by Web-Powered Manufacturing: • Collaboration with outside experts to extend their pool of resources • Management of remote and distributed operations • Tie-in of small operations to a larger operation • Monitoring a position in a JV operated by a partner • Managing a plant located in someone else's facility • Having a chemical supplier manage his inventory in a customer's tanks • Having an equipment supplier remotely troubleshoot his equipment installed in a customer's site • Having an additive supplier provide remote pro-active. guidance in optimization of a customer's operation • Having software suppliers take responsibility for the results of their applications • Outsourcing software and systems support by providing remote access Details of one of these opportunities are described in this article, and the benefits captured using this approach and the technologies necessary to make them a reality are emphasized.

Jan 1, 2002

By Robert S. Holmes

The U. S. Army Corps of Engineers Explosive Excavation Research Office (EERO) of Livermore, California, has been engaged in research and development of excavation techniques using both nuclear and conventional explosives since 1962. Prior to July 1971, this organization was designated the U. S. Army Corps of Engineers Nuclear Cratering Group. The EERO mission is performed as part of the joint Atomic Energy Commission -Corps of Engineers nuclear excavation research pro-gram. During the period 1962-1969, the Corps executed many cratering explosions using spherical charges of up to 85 tons of nitromethane to model nuclear excavation concepts and to develop design criteria for the nuclear cratering explosions. The experience gained in these modeling tests suggested that explosive excavation using large chemical explosive charges could be applied to excavation projects as an economical substitute for traditional excavation techniques. Consequently, the Corps' research program was broadened in 1969 to include development of chemical explosive excavation as a construction tool. The term "explosive excavation" denotes the use of large buried explosive charges to produce an excavation by fracturing the material and casting it into a desired configuration. In its simplest form, this technology involves detonation of a single explosive charge buried at the proper depth to produce a crater which is roughly hyperbolic in cross section. The types of craters produced by various depths of burial are illustrated by Figure 1. Single or Multiple rows of charges are used to excavate linear cuts required for water conveyance or navigation channels. .More complex explosive excavations include small craft harbors, railroad and highway cuts, and removal of W1denvater rock barriers to navigation. While the literature indicates widespread use of large explosions in the (1) ERRO is a field activity of the Waterway Experiment Station, Vicksburg, Mississippi

Jan 1, 1971

By E. M. Frizzell

An ongoing research program at the Spokane Research Center of the U.S. Bureau of Mines is directed toward investigating drilling parameters (thrust, torque, penetration rate, and drill revolutions) during the drilling of roof bolt holes. A system that measures these drilling parameters calculates the specific energy of drilling, and determines drill bit position has been developed by the Bureau and mounted on a roof bolting/drilling machine, through the use of a microcomputer, critical drilling parameters can be immediately interpreted and analyzed. This makes it possible to inform the operator of hazardous roof conditions. Initial results of this program are presented here.

Jan 1, 1990

By Harvey P. Knudsen

This paper illustrates the application of geostatistics to a roll front type uranium deposit located in Wyoming. The steps involved in calculation of experimental variograms, variogram modeling and verification of the resulting models are described in detail. The resulting spherical variogram models for grade thickness and thickness show strong geometrical anisotropies. The major axis of anisotropy for both variables is approximately parallel to the axis of the roll front and the minor axis perpendicular to the roll. This model confirms the technique of drilling "fences" across the roll front, where the drilling is much closer together than the fences along the roll.

Jan 1, 1978

By Xin Wang, He Shao, Wenpu Li, Yiyi Zheng, Xi Chen, Yurong Gao

This study utilized experimental and numerical simulation methods to investigate and analyze the atomization characteristics of three internal air–water mixed atomizers under different operating conditions. By comparing the research results, the effective dust control working parameters for the application of the selected atomizer in the engineering field were determined. Firstly, the atomization characteristics of the three atomizers were studied using a customized experimental system. The results indicated that nozzle 2 had a wide atomization range, a small atomization distance, and small droplet size; nozzle 3 had a narrow atomization range, large droplet size, and fast atomization speed; and nozzle 1 not only had a large atomization range but also could produce droplets of dry mist size with fast atomization speed, meeting the dust reduction requirements of the Majiliang Coal Preparation Plant. Secondly, Fluent software was used to simulate the atomization process and particle size distribution of the three internal mixed atomizers, determining the working conditions of the atomizers, the required number of atomizers, and the application angle of the atomizers in the internal mixed dust removal system. Finally, the atomized dust control system was applied on-site, achieving a total dust removal efficiency of 90.72% and a respirable dust removal efficiency of 89.75%.

Mar 9, 2024

By Rameshwar Sah, Somasekhar Pitchika, Akhil Singh, Seenivasan Rajiah, C. B. Dayanand, G. Balachandran

In the sintering of iron ores, the partial substitution of anthracite coal for coke breeze has been considered to be an effective way of reducing emissions and improvement in sintering properties. In the present study, the combustion characteristics of the anthracite coal and coke breeze were investigated and its influence on product sinter quality and sinter flue gases is being monitored. Pot trials are carried out with different coke breeze ratios, 0%, 40%, 50%, 60%, and 100%. It is found that as the percentage of anthracite coal is increased from 0 to 100%, the sintering time decreased from 24 to 20 min, and the productivity increased from 2.25 to 2.60 t/h/m2. Up to 60% anthracite coal substitution Tumbler index (+ 6.3 mm%), Product yield (+ 5 mm%), and fines generation (− 5 mm%) is found 62.29%, 85.17%, and 15.33%; moreover, hematite ( Fe2O3), magnetite ( Fe3O4), calcium ferrite phases ( CaFe2O4, CaFe3O5), and Silico ferrite of calcium and aluminum (SFCA) are major mineral phases found during microstructural analysis of product sinter. Keywords Sintering · Anthracite coal · Combustion rate · Productivity

Jun 2, 2022

By Daryl R. Tweeton

Bureau of Mines research in in situ uranium leaching includes injection well construction and environmental aspects. Clogging of injection wells is a common problem, and is affected by construction techniques. Part of the clogging can be caused by a low-permeability skin left on the borehole wall if the drilling fluids are not thoroughly flushed out. Certain polymer drilling fluids are less prone to cause clogging than bentonite muds, since a lower solids content can be used. The environmental research primarily involves two contracts. The first describes the environmental impact of in situ leaching and the effect of environmental legislation on leaching; the second describes the cost effectiveness of various methods of restoring ground water quality.

Jan 1, 1978

By Jürgen. F. Brune, CLAIRE STREBINGER, ADITYA JUGANDA, Gregory E. Bogin Jr

The abstract highlights the risk of methane gas explosions in underground coal mines and the potential of computational fluid dynamics (CFD) modeling to simulate such events and assess their impact on mine ventilation. The study focuses on developing CFD models for large-scale explosions in longwall mines, specifically simulating methane gas explosions resulting from face ignition during coal cutting. The research demonstrates the integration of a combustion model into a longwall mine ventilation model and shows how the availability of explosive gas mixtures significantly affects flame propagation and explosion pressure.

Mar 27, 2022

By Atta Ur Rehman, Kwame Awuah‑Offei

This paper examines the effect of bucket geometry (cutting blade profile, floor profile, and blade thickness), speed, motor power output, and muckpile particle sizes on bucket penetration and draft for rubber tire loaders. The work uses a 1:16 scaled model of a load-haul-dump in full factorial experiments to examine the effect of the variables on penetration and maximum draft. The results show that speed and motor output are positively correlated to penetration and draft; muckpile particle size is positively correlated to penetration and negatively correlated to draft (p < 0.0014). The results show that buckets with a semi-spade cutting nose profile yield the highest penetration (mean 118.30 mm) followed by those with the spade (mean 108.88 mm), which also yield higher penetration than those straight blades (mean 95.19 mm). Bucket floor profile and blade thickness had no significant effect on penetration or draft. Also, we determined that increasing the speed and motor power output, simultaneously, can reduce bucket penetration. Thus, operators should not waste energy for no additional gain or even loss in bucket penetration. Also, the work finds speed and motor power output each combine with muckpile particle sizes to affect bucket penetration. This research furthers our understanding of the effectiveness of different bucket geometries in improving penetration and reducing draft for rubber tire loaders.

Oct 29, 2021

By Alan J. Michaels

The paper addresses the problem of the high costs of accidents ad how AMAX Inc. - a diversified natural resources company - has managed to control its losses through a tri-thrusted approach of: (1) management commitment, (2) methods of implementation that are tailored to each division or local unit, and (3) a reward system for outstanding performance. Specific attention is focused on the Corporate Loss Prevention Department&apos;s "10 Point Program for Loss Prevention Management".

Jan 1, 1981

By Xin Zhou, Huilin Jia, Xiaofei Liu, Jinxin Wang, Zifeng Meng, Zinan Du, Hui Xie, Guihang Jiang

The change of gas emission or concentration level at the working face is one of the main precursor characteristics of coal and gas outburst. At present, coal and gas outburst monitoring and early warning are mainly based on whether it exceeds the limit and its change law. However, the gas concentration level is affected by factors such as coal seam gas content, permeability, and mining process, and the change law is complex to recognize manually. In this paper, the response characteristics of gas concentration level in the mining process are analyzed and revealed, and a bidirectional long short-term memory model is established. The change characteristics of the gas concentration level in the mining and non-mining processes are studied and recognized. The results show that the change law of gas concentration in the mining process has apparent periodicity and trapezoidal volatility. The proposed intelligent recognition method based on the bidirectional long short-term memory neural network can automatically recognize the underground mining and non-mining processes, and the recognition accuracy achieves 97.7% . The research can significantly help improve the level of coal mine safety management and the accuracy of early warning of coal and gas outburst.

Apr 29, 2023

By Xiaodong Yu, Jinxia Zhang, Fusheng Niu, Hongmei Zhang

The three-dimensional (3D) fractal dimension is an important parameter to analyze the 3D structure and flocculation effect of the hematite flocs. In this work, the 3D fractal dimension of hematite flocs was predicted by establishing the particle swarm optimization (PSO) algorithm optimized with the back propagation (BP) neural network (PSO-BP). The proposed model considers four factors, namely, the flocculant quantity, flocculation time, stirring speed, and temperature, as the input parameters. We normalize the input data during the preprocessing stage. The BP neural network was optimized by using the PSO algorithm for realizing the 3D fractal dimension. The prediction accuracy and effectiveness of the model were evaluated. The experimental results showed that the predictions performed by the proposed PSO-BP neural network were better than that of BP neural network. In addition, the root mean square error (RMSE), mean squared relative error (MSRE), mean absolute error (MAE), and mean absolute relative error (MARE) of the proposed model are lower, compared with the errors of the BP network. Similarly, the measurement coefficient R2 of the proposed model is higher, compared with the BP network. The maximum absolute error of the model is 0.0772, the maximum relative error is 0.02405, and the regression coefficient r is 0.98592. These results showed that the proposed model has a good performance and high prediction accuracy. When verifying the practicability and the effectiveness of the proposed PSO-BP model, the prediction results of 10 groups of hematite flocculation experimental data under different conditions showed that the prediction value of the proposed PSO-BP model was closer to the ground truth as compared to the BP model. Therefore, the proposed model is suitable for predicting the 3D fractal dimension of hematite flocculation.

Oct 3, 2022