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By David M. Rubio

The Ortiz Mine is an open pit-heap leach gold operation in central New Mexico processing about 3,100 tonnes (3,400 short tons) per day. It is the initial mining property in the United States developed by Gold Fields Mining Corporation, a subsidiary of Consolidated Gold Fields, PLC. This paper discusses the evolution of the present mining and ore control procedures as adaptions to the characteristics of both the rock being mined and the orebody, and with respect to the fact that mining is done by a contractor.

Jan 1, 1984

By Hossein Kazemi

This article is a review of fluid flow and mass transport in fractured rocks. The topics include: single-phase and multiple- phase flow theory, formation productivity or injectivity improvement by artificial fracturing, and mass transport associated with fracture acidizing. Possible extension and application of such ideas to in situ mining in fractured rocks are presented.

Jan 1, 1974

By T. R. Kostecki, A. J. S. Spearing, A. Hyett, M. Gadde

Ground control research for underground coal mining has progressed significantly over the past several decades. With this progression, and the ability to analyze and model underground conditions, underground working conditions have significantly improved. In order to progress further, the behavior of roof support must be known and be adequately modeled, such that models can be used for support design under different geological and mining conditions. This paper discusses the results from a research project funded by the U.S. National Institute for Occupational Safety and Health (NIOSH) and undertaken by Southern Illinois University Carbondale and Peabody Energy. The research involved installation of active and passive instrumented bolts in mines, recording relevant in situ data and then attempting to model the behavior of the bolts as mining progressed. Such calibrated models could aid in design of roof supports under different geological and mining layouts and thus, hopefully, further improve rock related safety.

Jan 1, 2012

By Ning Wang, Tengfei Guo, Wanyan Li, Hanjie Wen, Hannian Gu, Zehai Li

Bauxite residue (red mud) is an alkaline waste derived from the industrial process for extraction of alumina from bauxite ore. Some bauxite residues contain considerable concentrations of critical metals, for example, rare earth elements. Lithium in red mud was also reported as a potential resource. In the current study, a Li-rich red mud was leached using acetic acid to investigate the leaching behavior of lithium followed by neutralizing with hydrochloric or oxalic acid. By neutralizing red mud using diluted hydrochloric acid (0.01 mol/L), 58.04–60.27% of lithium was leached using 25% acetic acid at 95 °C for 60 min. In the meantime, more than 95% of sodium and 85% of calcium were also dissolved in the leachate solution. While oxalic acid (0.5 mol/L) was used to neutralize red mud prior to acetic acid leaching, lithium performed lower leaching efficiencies (42.41–46.88%) in comparison of using of hydrochloric acid–neutralized red mud. Nevertheless, these leaching efficiencies of lithium were close to that of calcium and much higher than those of sodium under the condition. In this study, 25% (v/v) of acetic acid, at 85 °C for 60 min, was demonstrated as optimum conditions for lithium extraction from oxalic acid–neutralized red mud using acetic acid. The results would be useful and of interest for lithium recovery and purification from red mud.

By Christine M. Kammer

In 1852, six barrels of iron ore were loaded aboard the steamer Baltimore at Marquette, MI, after a trip by mule wagon from the nearby Cleveland Iron Mining Co. Shipped to Sault Ste. Marie, they were portaged around rapids and reloaded onto another ship for the final journey to the steel mills of Cleveland. In 1855, the same company-the predecessor of Cleveland-Cliffs Iron Co.-chartered the brigantine Columbia to carry the first iron-ore cargo through the newly opened Soo locks. In 1981, about 2,190 iron-ore shipments in the form of taconite pellets were transported by water from US Great Lakes-ports. The total volume during the 284-day shipping season was 63 Mt (62 million It). Counting Canadian ship¬ments, almost 76 Mt (75 million It) of iron ore were moved on the lakes last year. The five Great Lakes-Superior, Huron, Michigan, Erie, and Ontario-contain 20% of the world's fresh water. The area surrounding the lakes has 26% of the nation's populations, 47% of its steel production, and over 80% of the raw materials required to make steel. That figure includes 71% of the country's iron ore and 40% of its limestone. Only the availability of low-cost water transportation of raw materials has kept the heartland steel producers competitive. Iron ore shipped on the lakes originates in the Lake Superior district's Mesabi and Marquette iron ranges. Major mines and their principal partners are Cleveland-Cliffs Iron Co.'s Empire, Republic, and Tilden; Armco and Republic's Reserve Mining Co.; Oglebay Norton Co.'s Eveleth; Hanna Mining Co.'s National and Butler; Inland Steel Co.'s Minorca; Pickands Mather & Co.'s Erie and Hibbing, the latter operated in conjunction with Bethlehem Steel Corp.; and US Steel Corp.'s Minntac. Pelletized ore products at these facilities is shipped through seven principal ports on the upper lakes: Duluth, Two Harbors, Silver Bay, and Taconite Harbor, MN; Superior, WI, and Marquette, MI, on Lake Superior; and Escanaba, MI, on Lake Michigan. In 1981, tonnage volumes ranged from 13.3 Mt (13.1 million It) shipped from Duluth, to Marquette's total of 5.4 Mt (5.3 million It). The ore docks, with two exceptions, are operated by railroads, most of which are owned by mining companies. Table 1 illustrates US iron-ore shipments in 1981. In the lower lakes, ore is discharged at dock facilities close to the great steel-producing centers of Chicago, Detroit, Cleveland, Pittsburgh, and Buffalo. Between the mines and mills, lakes and connecting waterways form one of the country's most effective transportation systems. Each year, vessels on the Great Lakes transport about 181 Mt (200 million st) of bulk industrial and agricultural materials-a greater quantity at a lower cost than can be achieved by any other transportation mode. Major commodities in Great Lakes trade are iron ore, coal, grain, limestone, cement, sand, and petroleum products. About 125 US flag vessels serve this trade, among them 13 "1,000-

Jan 10, 1982

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 J. Alderman

In modern industry, cost and productivity concerns and environmental concerns are sometimes incompatible, but at other times only appear to be incompatible. Surface disposal of wastes from coal preparation plants appears to be an area of the production system with little opportunity for initiating measures which cut costs and concurrently benefit the environment. However, improving the recovery efficiency of fine coal circuitry can cost-effectively reduce the plant waste environmental burden by a substantial amount. Studies at Jim Walter Resources indicate that fine-coal waste measuring 50% ash contains over 50% recoverable, marketable coal. Modifications to the plant circuitry which reduce the amount of misplaced coal in the fine-coal waste stream could substantially reduce the volume of fine waste disposed aboveground. Studies at Jim Walter Resources indicated that episodic overloads of the vacuum filters in the fine-coal circuits at the preparation plants were a source of misplaced coal in the fine-waste stream of the cleaning plants. To improve the filtration rate and reduce overload episodes, conventional rotary blowers were replaced with high pressure air blasters on most of the filters. Subsequent testing indicated that measurable benefits can be derived from this modification.

Jan 1, 1990

By Perry N. Halstead

The primary objective of the structural geology portion of the Kennecott Copper Corporation-U. S. Bureau of Mines Pit Slope Stability Study was to determine the attitude, geometry, and spatial distribution of geologic structures of the west wall of the Kimbley Pit for use in designing a maximum stable slope for the pit. A corollary objective was to develop and refine techniques for collecting and analyzing geologic structural data with emphasis on numerical methods that could be integrated with other aspects of pit design. Surface mapping techniques used were a modification of conventional joint set mapping and a detailed linear sampling method. For subsurface investigations both oriented core and a borehole camera were used. It was determined that the major faults in the area were favorably oriented for mining a steep stable slope. The jointing or natural fracturing, although complex, was not random in attitude and consisted of several persistent fracture sets and a number of secondary sets. The attitude of the persistent fracture sets was favorable for steeper slope angles, and these attitudes were used in the design considerations. There was no significant difference between the attitude of the fracture sets determined from the former and new slope face.

Jan 1, 1968

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 Malte J. M Gurgel

Subsurface spatial planning is becoming increasingly important in view of competing underground applications. This development is influenced by global agreements to reduce greenhouse gas emissions. Therefore, precise knowledge of the underground space is a basic prerequisite for future applications. The three-dimensional registration and reliable georeferencing of underground infrastructures can establish a holistic geodata basis for such tasks. Those tasks are discussed both for the development of energy projects such as deep geothermal energy as well as for storage applications. Research on geothermal energy has been carried out at RWTH Aachen University as part of the SuperC project in a license field in the Aachen area since 2001. Recently, this research has been extended to include monitoring aspects in the overlapping GEObservatorium Aachen field. The documentation and visualization of underground activities using photogrammetric methods like Structure from Motion is discussed based on recent research in sites for the final disposal of radioactive waste. Finally, both applications provide an outlook on supporting underground projects by using high-resolution geodata.

Feb 1, 2025

By A. Chieregati

"A heterogeneity study was conducted at Erdenet Copper Mine in Erdenet, Mongolia, to determine the fundamental sampling error associated with blasthole sampling. Using a custom designed sector sampler, six large blasthole samples were collected to perform the test that was developed by Pierre Gy, to estimate the constitutional heterogeneity factor for several types of ore. The study investigated the entire sampling protocol, from mine site to analytical laboratory, and quantified the contributions to fundamental sampling error (FSE) of the various stages of sampling and sample preparation. The total relative standard deviation (RSD) of sampling error was determined to be ±32% and ±49.4% for copper and molybdenum respectively. A classical statistics analysis conducted on the data confirmed the level of RSD. About 95% of the sampling error was produced from only one step in the sampling protocol: when the 1 kg sample was reduced to 50 g sample for chemical analysis. Therefore, it is recommended that the 1 kg sample be reduced to 50g using a slightly different protocol to minimize the FSE. The 1 kg sample should be first crushed to 0.2cm size. A 250g split should then be taken and fine ground. A 50g split should then be taken from the 250g fine ground split. These two simple steps will reduce the FSE to ±7.9% and ±17% for copper and molybdenum respectively. The modified sampling protocol effectively reduces the probability of misclassification of low grade ore to zero. INTRODUCTION The Erdenet copper-molybdenum open pit mine is located in Erdenet, in Orkhon province, Mongolia. The Erdenetiin-Ovoo copper-molybdenum deposit is between 1.5 and 3 km wide, and about 25 km in length (Erdenet Mining Corporation, 2016). Chalcopyrite, bornite covellite and chalcocite are among the major minerals found in the deposit. The mine processes approximately 26 million tons of ore annually. A study was conducted to evaluate the fundamental error associated with the blasthole cuttings and sampling protocol at the mine. The open pit mine uses 215mm diameter Russian drills to drill 17.5m holes for 15m benches. The total weight of blasthole cuttings for a 215mm diameter hole and 15m bench height is between 1.5 and 2 tonnes. This amount of sample is difficult and time consuming to collect and analyze. Therefore, a sector sampler was designed for the Russian drills to collect large samples that were representative of the blasthole cuttings (Ganguli et al., 2016). In order to eliminate the delimitation and the extraction errors, researchers consider sector samplers to be ideal for sampling blastholes (Pitard, 2008; Chieregati and Pitard, 2009). This method was intentionally more rigorous than the blasthole sampling protocol at the mine to ensure that the blasthole cuttings were properly sampled. This study was part of a broader study that also looked at the relationship between particle size and grade. The samples collected by the custom designed sector sampler were very large (195 kg on average), and therefore, sufficient for both studies. The relationship between particle size and grade has been reported in Ganguli et al. (2016)."

Jan 1, 2017

By Corby G. Anderson, Sheikh Abdul Rezan Sheikh Abdul Hamid, Sanjith Udayakumar, Ahmad Fauzi Mohd Noor, Teuku Andika Rama Putra

Chemical and mineralogical characterization of Malaysian monazite, a phosphate mineral, bearing rare earth elements separated from the tin tailings originated from Ipoh, Perak, Malaysia, was performed in this paper. The study aims to collect detailed information on the chemical composition, crystal phases, and microstructure of the mineral monazite concentrate that would aid to optimize the subsequent hydrometallurgical processes for high-efficient separation of thorium and other associated rare earth elements. A systematic characterization study of the concentrate was conducted using techniques such as optical microscopy (OM), scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared spectroscopy (FTIR). These techniques analyzed the morphological details on the surface, elemental analysis, and mineral association assessment and identified the surface functionalization groups. The bulk composition and the mineral phases in which the elements are present were studied by wavelength-dispersive X-ray fluorescence (WD-XRF) and X-ray diffraction (XRD) studies respectively. The XRF analysis confirmed the presence of Ce, La, Nd, Pr, and Y (rare earth oxides: REO’s ~ 60 wt.%) while thorium dioxide (ThO2) accounted for 7 wt.% of the total composition. Traces of Ca, K, Al, Fe, Ti, and Mn were also confirmed by SEM elemental mapping. The XRD results confirmed that the concentrate was primarily composed of monazite (Ce, La, Nd, Th (PO4)) along with minor impurity phases of quartz. Automated mineralogical analysis was used as a confirmatory tool to corroborate the preliminary evidences. Based on the particle size distribution analysis supported by SEM, the majority of monazite grains were found to be present in the size range of 170–210 μm. Strong bands of PO4 and SiO4 were observed in the IR spectra corresponding to the phospho-silicate matrix of the REE mineral.

By Harrison R. Cooper

Approximately 40 concentrators throughout the world have successfully adopted computer control for flotation circuit operation since 1969. Successful use of flotation control, gaining up to 2% efficiencies, has largely derived from effective employment of on-stream slurry analyzers and integration of key measurement data through digital processors. Requirements for reliable measurement have also led to improved functional reliability in magnetic flow meters, pH, reagent feed, and other key elements. Methods used in computer control of flotation will be reviewed and variations in operating philosophies will be described with reference to the approaches taken to flotation automation.

Jan 1, 1979

By M. Fig, J. Brune, C. Strebinger, G. Bogin

"A fundamental understanding of flame propagation characteristics through and around obstacles is needed to accurately model methane driven longwall coal mine explosions originating or propagating in the gob. Experimental investigations of methane flames in horizontal cylindrical reactors with simulated gob (i.e. rock piles) were carried out alongside coupled Computational Fluid Dynamics (CFD) and combustion simulations. Stoichiometric methane-air mixtures were ignited in semi-open reactor vessels of 5cm, 9.5cm and 71cm diameter, all with a fixed length to diameter (L/D) ratio of 8.6. This was done both with empty reactors and also with a rock pile placed at the open end of the reactor. The rock pile length to reactor length ratio was fixed at 0.3, and the rock pile height to reactor diameter ratio was fixed at 0.33 for all reactors. The smaller two reactor experiments were modeled with ANSYS Fluent in 2D. Experimental results indicate that for this geometry a similar acceleration mode occurs across scales: that the flame speeds up an average of 40% as it passes over a rock pile with this profile. The model is able to capture several important features of the experimental results, including the significant increase in velocity, the speedup ahead of the rock pile, and the leveling off of the empty tube flame front propagation velocity. INTRODUCTION Explosions in underground coal mines are among the largest industrial explosions, known to result in the rapid combustion of 20m3 of fuel gas or more [1,2] Coal beds hold methane gas under pressure, and when the pressure is relieved through mining activity some of this methane is released. The methane then mixes with ventilation air and, if not sufficiently diluted, may form a combustible mixture, which may result in an explosion. Several large coal mine explosions have occurred around the world recently. These include the 2014 Soma Mine disaster in Turkey that killed 301 people [3], and the 2009 Heilongjiang Mine explosion in China that killed 108 [4]. Other recent mine explosions, including the 2010 disaster at the Upper Big Branch mine that caused 29 fatalities [5], have demonstrated that explosive gases can accumulate and ignite within and around the gob area of a longwall coal mine and then expand into the active mining face and nearby areas, endangering workers and equipment. If enough combustible gas is involved, the initial flame can accelerate, eventually transitioning from deflagration to detonation [6]. Researchers are developing a fundamental understanding of the evolution of the explosion process from the laminar kernel to the fully turbulent regime, and its propagation through obstacles such as those found in the gob. Researchers also studied the initial development of methane flames and the potential for the development of a detonation."

Jan 1, 2018

By F. Sill

The disposal of residual material from processing and combustion of coal, from incineration of domestic refuse and sewage sludges kind to the environment is a prior task for the future. Deutsche Montan Technologie (DMT) has developed a new technique which makes possible to fill-up goaf cavities behind running caving systems in coalmining. In a mixing and pumping station on the surface high concentrated suspensions are produced from the above mentioned materials. The paste is pumped through pipes to the coalfaces and via trailing discharge pipes stretched to the fracture zone in the caved-in goaf. Since three years a special designed plant is working successfully on a coal mine of Ruhrkohie AG.

Jan 1, 1994

By R. L. Clayton

The Bagdad district is 67 kilometers west of Prescott, Arizona, (Figure 1). The area north of the Old Dick and Bruce Mines was originally mapped by Anderson, Scholz and Strobell between 1943 and 1945, (1). The region is perhaps better known for the Bagdad porphyry copper deposit of tertiary age. However, 2 to 5 kilometers south of this deposit are several small massive sulfide occurrences in a eugeosynclinal Precambrian greenschist environment. More specifically, in. the Bridle formation of the Yavapai schist series. Three of these mines - Old Dick, Bruce and Copper Queen - were mined by Cyprus Mines Corporation between 1957 and 1977, and produced nearly 2mm tons of 3.6% copper and 12% zinc. These deposits occur at the interface between andesite and rhyolite and are stratiform in character. Certain structural and textural properties of the Bruce orebody suggest that remobilization of the massive sulfides occurred at some period during the metamorphic history of the area.

Jan 1, 1978

By H. Maleki

The U.S. Bureau of Mines pioneered the use of borehole deformation gauges and overcoring techniques to measure in situ stress. These measurements provide input to structural mine design and support selection for specific geologic conditions. This paper presents recent stress measurements in a western U.S. coal mine where the orientation of the stress field remained relatively unchanged over distances of several kilometers. The horizontal stress magnitude increased with depth of cover and in relation to major geologic structures. Local variations in roof stress profiles were used to develop generic models relating stress arching to strata stiffness and the inelastic behavior of mine roof.

Jan 1, 1994

By Kevin Lofftus

The rest potentials of molybdenite electrodes are measured as a function of pH in absence and presence of flotation reagents. The chemicals used include sodium ethyl xanthate, kerosene, dextrin,sodium hydrosulfide, hydrated sodium molybdate, sodium sulfate, and hydrated sodium thiosulfate. The effect of dissolved oxygen is also noted. The obtained data are correlated with the results of micro-flotation tests obtained under similar chemical conditions.

Jan 1, 1984

By CADEN VITTI, Barbara J. Arnold

Mine tailings, the byproduct of mining and mineral processing, are increasingly mass produced as a result of increased demand for metals and minerals as well as the advancement in technology that allows for the exploitation of lower-grade ores. Lower grades can increase the volume of tailings that may contain new gangue minerals that should be evaluated for the presence of critical minerals and other valuable metals. The practice of reprocessing, while relatively new, is crucial to reducing environmental damages, obtaining valuable critical minerals from waste, and contributing to more sustainable repurposing and disposal methods. With the increase in tailings dam failures in recent years, there is a large motivating factor in remining and removing the potential hazard to benefit the safety of potentially impacted communities. In analyzing the perspectives of various domestic and international studies, this literature review will determine the feasibility of reprocessing and reutilizing mine tailings waste for a more sustainable future while exploring current practices that have benefitted ecosystems and communities.

Jan 1, 2022

By Norman E. Lehman

INTRODUCTION The Washington Camp - Duquesne mining district is located on the east flank of the Patagonia Mountains, 98 kilometers south of Tucson and within 5 kilometers of the International border (Figure 1). Since the development of high-grade silver and copper ores by settlers in 1862, the Washington Camp - Duquesne district has yielded an estimated 450,000 metric tons of ore. The mined ores averaged 8% zinc, 2% copper, 3% lead and 124 grams of silver. REGIONAL GEOLOGY The Patagonia batholith, of Laramide age, crops out in the core of the Patagonia Mountains intruding Precambrian granite, Paleozoic sediments and Mesozoic igneous, volcanic and clastic rocks. This granodioritic batholith lies in a northwest-trending zone of Laramide plutonic rocks, which can be traced for a distance of 320 kilometers from the Nacozari district in Sonora, Mexico to the Silver Bell Mountains west of Tucson, Arizona. Several major porphyry copper systems occur within this plutonic belt including the Red Mountain deposit found at the northern end of the Patagonia Mountains. Data from more than 80 mineral deposits within the Patagonia Mountains show metal zoning symmetrical to the Patagonia granodiorite (Graybeal, 1975). Disseminated copper-molybdenum deposits occur within the batholith. Pyrometa-somatic, limestone replacement and vein deposits of copper, lead, zinc and silver occur in the wallrocks adjacent to the. granodiorite and epithermal manganese-silver deposits occur at the outer periphery of economic mineralization. GEOLOGY OF THE WASHINGTON CAMP - DUQUESNE DISTRICT Stratigraphy Nearly 900 meters of miogeosynclinal Permian and Pennsylvanian sediments are exposed in the district (Figure 2). In addition, 700 meters of older Paleozoic rocks crop out 6 kilometers north of the district. The Paleozoic rocks occur in fault contact with a sequence of Triassic-Jurassic pyroclastic and flow rocks, ranging in composition from latite to rhyolite.

Jan 1, 1977