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By J. V. Thompson

The Powderhorn complex as a source of perovskite (calcium titanate) containing about 1.5% rare earths has been examined in several recent feasibility studies. Much promising exploration and process research has been done in recent years. This paper is presented with cautious optimism and with the acknowledgment that there may be some technical and economic areas yet to be explored. The Powderhorn carbonatite and alkalic stock in Gunnison County, Colorado, lies about 203 airlines km southwest of Denver at an elevation of 2450 to 2750 m (see Figures land 2). All of the mineable ore bodies are owned by Buttes Resources Company of Houston, Texas.

Jan 1, 1990

By J. Diao

In order to understand the flotation kinetic behavior of coal and associated mineral matter, a detailed investigation was conducted in a 2-liter Denver flotation cell using three high sulfur coals at three feed sizes, minus 28. 100 and 200 mesh. Subsequently. the flotation products were sieved into different size fractions and analyzed for their ash and pyritic sulfur content in order to delineate the effect of particle size on the rate at which each constituent floats. The results were tested with several different flotation kinetic models and the best model for coal was then chosen. The flotation rate constant and the ultimate recovery calculated from a kinetic model were used to delineate the effect of particle size, collector (dodecane) and frother (MIBC) dosages on the flotation kinetics of coal, ash and pyrite.

Jan 1, 1992

By Geoffrey G. Hunkin

This is a brief state of the art paper describing current (1975) Uranium recovery plant flowsheets, some notes on system selection, design philosophies, and materials of construction. The in-situ, or borehole solution mining, of Uranium is a process which has been developed over recent years to better match Uranium mining and milling technology with the size, shape, grade and territorial distribution of the remaining identified Uranium deposits of western United States. Solution mining recovery plants are pure hydrometallurgical units ideally suited to automation, modular design, and mobility. Similar to conventional Uranium mills, two basic flowsheets, one acid and one carbonate, are in use, but the predominance is reversed so that the majority of plants employ the alkaline carbonate flowsheet, All plants incorporate resin bead ion exchange Uranium recovery for both acid and alkaline circuits.

Jan 1, 1976

By Ma Lianren, Wang Duolun, Chenzhe Li, Hongyan Xie, Fenglan Luo, Huixin Jin

In this study, the oxidation of low-grade pyrolusite to potassium manganate in alkaline solutions under O2 pressure has been investigated. The effects of different conditions on the high-grade and low-grade pyrolusite leaching process were investigated based on thermodynamic calculation, as well as the reaction mechanisms and kinetics of the low-grade pyrolusite during the leaching process. The results showed that the manganese conversion rates of the two types of pyrolusite were almost the same, and reaching 99% for high-grade pyrolusite and 96% for low-grade pyrolusite under optimal conditions. The optimum condition for low-grade pyrolusite sample JM-2 was achieved as 0.5 MPa of the oxygen partial pressure, 55% of KOH, 14 of the initial alkali-manganese ratio, and ≤ 48 μm of the mineral granularity at 260 °C within 150 min of leaching time and 500 rpm. In alkaline leaching of low-grade pyrolusite, Mn(IV) was oxidized into Mn(VI). The particles changed from large particles to flakes and finally formed crystals. Finally, the shrinking core model was used to fully describe the leaching kinetics of the manganese. It was demonstrated that the leaching of manganese was controlled by the chemical surface reactions and the activation energy which equals 115.9121 kJ/mol.

Dec 3, 2022

By Klaus Grebe

Recent investigations by Mannesmann Research have shown that disintegration of sinter with widely varying quality levels is subject to a much more complex set of influences than was previously assumed. It was confirmed that disintegration at temperatures between 300 and 600 °C is triggered by the degradation of hematite. The specific tendency of hematite to disintegrate is, however, not constant: sinters containing the same amount of hematite can show widely differing disintegration tendencies depending upon structural homogeneity, porosity and gangue quantity. Especially sinters with heterogeneous structures transmit stress to the hematite phase and this favours disintegration. Another factor is the brittleness of the glassy silicate phase, which can be influenced even by small modifications of minor gangue constituents.

Jan 1, 1981

By I. Mazalov, G. Ospanova

Introduction Today, uranium is of great interest because of its application to nuclear power and nuclear weapons. Kazakhstan has been an important source of uranium for more than fifty years. All uranium products are exported. Results In Kazakhstan uranium exploration started in 1948 and developed in several parts of the country thru mining of hard rock deposits. There are known around 50 uranium deposits in six provinces: Shu-Sarysuyskaya (57%), North Kazakhstan (18%), Syrdaryinskaya (15%), Ilyiskaya (7%), Caspian (2%), Balkhash (1%). In the Northern Kazakhstan province, KazSabton took over Tselinny Mining & Chemical Co in 1999. In this province the stockwork is of Paleozoic and Paleozoic folded complexes origin. In the Balkash province some mining of volcanogenic deposits occurred during the Soviet era. This province’s stockwork is of Endogenous origin.In the Ili province uraniumis mainly found in uranium-coal deposits formed by oxidation of the lignite beds roofs. In the Caspian province the Prikaspisky Combine operated since the 1960s a major mining and processing complex on the Mangyshalk Peninsula. This led to the founding of Aktau. It was privatised as Kaskor in 1992 and operations ceased in 1994. The uranium occurrence is associated with the phosphorous from fossil fish bone detritus conglomeration. In the Chu-Sarysu province, which has more than half the country's known resources, both Stepnoye and Tsentralnoye have been operating since 1978 and 1982 respectively. Uranium mineralization occurred in the regional stratum oxidation zones. In the Syrdarya province slightly to the west of the province’s center the No.6 Mining group has been operating since 1985. Uranium mineralization occurred in the regional stratum oxidation zones.

Jan 1, 2007

By Derrick Chambers, George Kevin Chapin, M. Shawn Boltz

Seismic monitoring is one of the few noninvasive technologies with the potential to provide sub-surface geomechanical information to operators of large open-pit mines. Although passive seismic data has been used to refine emerging failure geometries and provide advance indication of surface deformations in the literature, doing so reliably in an operational context is much more difficult. This is due in part to difficulties in estimating and interpreting source locations and parameters in complex, low-stress open-pit environments. Additionally, the high costs associated with implementing, operating, and maintaining deep borehole seismic networks, which are most commonly used to monitor large open pits, can be difficult to justify, especially if monitoring benefits are not readily apparent. In this study, we explore the use of a near-surface nodal seismic deployment, which is commonly used in oil and gas exploration, for monitoring open-pit mining-related seismicity on a short-term basis. A deployment of 18 geophones was conducted on the surface in and around the Bingham Canyon Mine, a large open-pit mine near Salt Lake City, Utah, USA, where we find the small seismic array can detect and locate a variety of mining-related seismic sources, even with an extremely simplified velocity model. We outline the process of creating an idealized velocity model, developing a local magnitude scale, and interpreting the observed seismicity. Of note, we analyze a sequence of mining-induced events associated with a known structure on the south pit wall. We conclude with discussion on how surface-based deployments may be used to augment, or in some cases supplant, borehole seismic networks at large open-pit mines depending on monitoring requirements and objectives.

Apr 26, 2022

By Tedd B. Bodimer

Why complicate an already complex machine such as a continuous miner by adding roof drills? Immediate permanent roof support is an immediate thought of the mining engineer just as elimination of frequent time-consuming places changes is a thought of the methods engineer. The realization of those two objectives has the potential for improved safety with increased production is the thought of the general manager. Miner-Bolters Used a Generation Ago These are not new thoughts as the 1CM continous miner equipped with two integral roof drills was introduced twenty-five years ago. Approximately two hundred of these machines were sold in the next five years for use in medium and high seam operations. The 1CM miner chassis that remained stationary in the center of an entry or room while the ripper bar was swung and sumped hydraulically provided an ideal platform for mounting two roof drills that could be operated during the continuous miner's production cycle. Two roof bolts could normally be installed in less time than required for the mining cycle. A typical roof drill unit is shown in Figure I.

Jan 1, 1981

By Willard C. Lacy

INTRODUCTION A program to insure adequate talent for development and management of our mineral resources entails two equally important and interrelated aspects: 1) attracting and retaining promising student talent, and 2) providing a first-rate education for those entering careers in mineral science and engineering. Manpower shortages have eased in many areas of engineering, particularly in those areas dependent directly or indirectly upon government contracts in space and war programs. However, in the minerals industry the needs still remain critical. As increasing concern over preservation of the environment has developed, the political and social reaction was to seek out major offenders, to look for "whipping boys" -- and the mineral industry was, and had been, an offender. It was there for everyone to take pictures, it couldn't be covered up, and the Department of the Interior lashed away in the beautiful and popular brochures: Quest for Quality, The Third Wave, The Population Challenge, and Surface Mining and Our Environment (Ravaged Land). The Sierra Club, the Field and Stream magazine, TV, and daily news media added their lashes. In the minds of our social-conscious youth the mineral industry took on the image of "exploiters" of natural resources; "polluters" of streams, lakes, and the atmosphere; "despoilers" of wilderness areas and scenic beauty -- a plague to combat, rather than an exciting challenge that entailed exploration of the remote, conquering of the primitive, and developing of the undeveloped. Enrollments declined and many traditional mineral engineering curricula were abolished or Integrated into other stronger engineering departments to meet student-faculty ratio requirements.

Jan 1, 1971

By Amanda Powers, Brian Glynn, Robert Sauceda, Daniel Huffines, Mike Garbeth

This paper will review the evaluation performed for the Cottonwood & Hackberry Creek Wastewater Interceptor Improvements Project to replace two separate aging and undersized interceptor sewers by either open cut construction or trenchless construction methods. A case study will be discussed for the utilization of microtunneling to avoid a deep open cut excavation within a landscaped roadway median to construct nearly a mile of new 60-inch interceptor sewer in an urban area adjacent to an environmentally sensitive riverine area, while minimizing the permitting and environmental impacts of construction, and minimizing the impacts to residents and vehicular trafc and restoration reuirements.

Jun 23, 2024

By R. L. Grayson

Using powerful database management software, nested-field analysis and microanalysis of narratives have been made of West Virginia accident data, resulting in a new approach for targeting and prioritizing safety interventions by county, mine size, specific mine, job title, type injury, etc. and combinations of these parameters. The analyses have been useful in focusing training and discussion sessions on specific work problems, trends, conditions, and situations for targeted groups of miners. Application of the technique will be presented in this paper, along with comparisons of various mine performance measures.

Jan 1, 1997

There are presently in use many grinding mill control schemes and concepts. This paper presents one operating method of controlling the particle size of the cyclone overflows for proper metallurgical results and controlling the level of the cyclone feed sump and new feed rate to obtain lowest unit cost of finished (ground) material which is usually at the maximum grinding mill throughput. This system stresses simplicity of field instrumentation and control strategy. Both of these factors lead to better operator understanding and acceptance. The low capital investment of this system also makes it more attractive at the Buick Concentrator when compared to other more complicated systems utilizing mass flow measurement and a computer to calculate circulating load and infer particle size. Furthermore, it has the advantage of utilizing an actual measurement for control, rather than a difficult-to-maintain inferred value. There are several reasons for maximizing mill throughput at Buick. The milling rate before automatic control was too low when compared to mill throughput increases planned for the future. Through this new operating system, it appears Buick will not have to make major changes of mill motors and speeds to meet the increased? production rate. Also, since power costs continue to escalate, it is desirable to maximize the throughput to the grinding circuit and reduce overgrinding to achieve a reduction in power cost per ton of ore milled. Presently, 45% of the concentrators' total power is consumed in this grinding circuit.

Jan 1, 1977

By Caibin Wu, Bin Xie, Jiaqi Tong, Ningning Liao, Chong Zeng

Understanding the energy-size reduction relationship is vital to grinding process; therefore, this paper aims to show the energy-size reduction of magnetite-calcite binary mixture in a laboratory wet conical ball mill. Single magnetite, single calcite, and blended magnetite-calcite mixture at three weight ratios in four particle sizes were ground in a laboratory wet conical ball mill at four grinding time periods. The results showed that the particle size distribution of both fine particles and coarse particles of single and mixture ground product fitted well with the PSD computed by Rosin–Rammler-Benne function. The larger mass percentage of calcite is, the higher t10 of binary mixture ground product is. On the contrary, t10 in the mixture decreases as the percentage of magnetite in the mixture increases. The different breakage behaviors in blended samples are due to the hardness and particle size. The results of calculated ratio of energy absorption factor showed that the calcite consumed more energy in the breakage process of binary mixture than ground alone. The JK size-dependent breakage model based on the t10 method fits all the experiment data, be it generated from pure minerals, mixtures at different weight ratios, or each component separated from the mixture.

Jun 4, 2022

By Kadri Dağdelen, Matthew Deutsch, Thys Johnson

Nested pit analysis in open-pit long range mine planning is used to define approximate ultimate pit limits and an initial high-level schedule in the early stages of a project. Modern ultimate pit optimizers can solve for dozens, or even hundreds, of nested pits however often a smaller subset of pits which are evenly spaced with respect to contained tonnage are desired for downstream analysis. In situations where that pushback selection process must be automated, such as when performing sensitivity analysis, or when the best subset of pushbacks is required; an optimization procedure is warranted. This paper describes a dynamic programming algorithm for selecting pushbacks following nested pit analysis, which is performant and addresses a long-standing inconvenience faced by long range open-pit mine planners.

Jun 25, 2023

By Anuradha Khetwal, Tala Tahernia

The estimation of TBM utilization rate can be problematic due to the uncertainty involved in the tunneling system reaction to various geology along the tunnel. Moreover, the impact of operational and management issues on TBM performance is unsettled. This includes the occurrence and duration of downtimes and the uniqueness of projects relative to the geology, machine type, backup system, site setup, crew experience, and operational restrictions imposed on the project by localities. The CSM2020 is a model based on discrete event simulation that predicts machine utilization for single or double shield TBM. This model was developed by the Earth Mechanics Institute (EMI) team, using the database of tunneling activities which was compiled based on field observation and measurements in pertinent projects. In the current study, CSM2020 was modified to simulate the workflow of slurry TBMs. The operating principle of slurry shield TBMs is different than open-mode TBMs. The model was verified by comparing results with a recently completed project in the United States. As a result, the model offers reliable utilization rate estimation in different types of TBM by implementing appropriate workflow.

Dec 1, 2022

By C. W. Schultz

Earlier publications from The University of Alabama have indicated that column flotation performance is improved when operating at low pulp levels and when the feed is directed into the froth phase. To validate these early observations a series of tests were performed in which the position of the feed entry to the column and the pulp-froth interface were systematically varied. The optimum grade-recovery relationship was achieved with high feed entry (WA) of column height) and very low pulp levels (<10% of column height). The position of the pulp-froth interface appears to be the more critical variable. When operating in this mode (1. e. at low pulp levels) column flotation becomes. in reality. a froth separation process.

Jan 1, 1991

By Josh B. Taggart

Some twenty to twenty-five years ago we saw the beginning of mechanization in our coal mines, It has now progressed to the point Chat as instruments of production the pick and shovel are things of the past, They had to give way to better and more efficient methods--so mechanization, followed by and combined with automation, has become common-place in our mines. Our coal could not keep its competitive position without this progress Without it our industry could not look to the future with any degress of confidence. Today we lock back and see cases of regained and salvaged markets. We see better coal products being produced at decreasing costs. We see better utilization of manpower and a stronger, more confident industry, Our hats arc off to those mining men, equipment manufacturers, labor leaders, and others who had the foresight to work toward these ends and the ability to bring them about.

Jan 1, 1962

By F. J. Sotillo

"Scrubbing both horizontal (drum) and vertical (attrition) are considered simple unit operations in the beneficiation of phosphate ores. In general, the operating conditions are fixed at high solids content based on the experience of the engineering or equipment manufacturing company responsible of designing this beneficiation step. Nevertheless, scrubbing is a complex unit operation designed to clean the surfaces of phosphate mineral particles of slimes, break loose weak inclusions or attached particles of impurities, and break aggregates of clayish material. Therefore, it is considered that as high solids content as possible should be used to enhance particle-particle interactions (impact and rubbing) without taking into consideration the rheology of the system. However, scrubbing unit operations design requires studying the balance between the increase of particle-particle interactions with the cushion effect that may occur when slimes, clays and fines decrease the availability of free water increasing the apparent viscosity of the phosphate slurry up to that of a paste consistency. This paper presents data from laboratory tests to determine the best operating conditions for the design of these unit operations based on the highest P2O5 grade obtained with the lowest impurities for different size fractions. INTRODUCTION In the beneficiation of phosphate ores, unit operations such as horizontal scrubbing (drum) and vertical scrubbing (attrition) are considered simple unit operations. Therefore, little attention is given to the design of horizontal and vertical scrubbing during the basic engineering studies, and the detail engineering stage, the manufacturers recommending “standard” units and operating conditions based on their experience. Due diligence of several beneficiation phosphate plants at industrial scale indicates that a deficient scrubbing of the phosphate ore results in significant problems in downstream unit operations, such as classification, clarification, gravity separation, magnetic separation, flotation, dewatering, and filtration. Scrubbing is in fact a complex unit operation designed to clean the surfaces of phosphate mineral particles of slimes (clays and fines), break loose weak inclusions or attached particles of impurities, and break aggregates of clayish material. Two phenomena occur, the particle-particle interaction (impact and rubbing), and the rheological effects of releasing significant amount of fines into the slurry. Therefore, high solids contents are recommended to enhance the particle-particle interactions, which may result in a change in the rheological regime of the system due to the slimes, clays, and fines decreasing the availability of free water. This increases the apparent viscosity of the system up to that of paste consistency resulting in a cushion effect that suppresses scrubbing. Under these conditions, not all fines are release and rejected (deslimed), downstream unit operations being affected by the release of clays, resulting in P2O5 losses."

Jan 1, 2017

By R. H. Sergent

The interest in using halogens for extracting precious metals from ores has increased due to changes In ore characteristics, environmental concerns and regulations. The rediscovery of halogen leaching capability has been the topic of these and other writers1-30. Much work has been done on the performance of bromine, chlorine and iodine5-29. Of these, bromine and chlorine look most promising. Iodine is quite expensive and sometimes forms an Insoluble film on a precious metal surface22,23. Little experimental work has been published on the relative performance of bromine versus chlorine. The Pourbaix diagrams for the halide leach system (see Fig. 1-4) Indicates a significant stability advantage for bromine In forming complex ions with gold. This should result In greater extraction of gold under similar leach conditions and Is evaluated In this work. The regeneration of halogen from a spent leech solution is a critical requirement for an environmentally acceptable halogen leach process. Bromide can be oxidized In-situ to bromine ~ adding chlorine or ozone2,31. Bromide like chloride can be oxidized In an electrochemical cell to produce halogen on demand 13,15,17. Bromine clearly offers a number of possible regeneration pathways. This work strives to compare the relative ability of chlorine and bromine to extract gold from partially and fully oxidized ores. A commercially pressure oxidized sample was evaluated under a number of experimental conditions. The autoclave feed ore from the same mill was also evaluated after complete oxidation In a laboratory autoclave.

Jan 1, 1993

By Ashley Woodward, S. Katharine Hammond, Mayela Padilla-Salas

This paper presents a scalable framework for worker safety assessments. The paper focuses on uranium mine reclamation in underserved communities, specifically Cove Chapter of the Navajo Nation. By integrating field observations, OSHA data analysis, systems mapping, and a hierarchical occupational health pyramid, this framework identifies site-specific hazards while addressing broader socio-cultural dynamics. The approach improves upon existing safety programs by suggesting actionable, locally sensitive solutions that prioritize higher-order controls such as hazard engineering interventions and administrative controls. This study contributes to enhanced worker safety, efficient environmental restoration, and engagement in marginalized communities with abandoned mine lands.

Feb 22, 2026