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By Yuanyuan Wang, XUEWEN WANG, Jinzhi Wei, Ligang Wen, Muxin Jia, Zhengyao Li

The abstract discusses the use of disodium carboxymethyl trithiocarbonate (D8) as an effective depressant in the flotation separation of stibnite and pyrite. The study investigates the mechanism behind D8's selective inhibition of pyrite, utilizing techniques like micro-flotation experiments, contact angle measurements, infrared spectroscopy, adsorption capacity analysis, and zeta potential measurements. The findings reveal that D8 physically adsorbs onto both pyrite and stibnite, but its adsorption capacity on pyrite is significantly higher. This adsorption enhances the hydrophilicity of the pyrite surface, hindering the adsorption of the collector and effectively depressing pyrite flotation, while having minimal impact on stibnite floatability.

Mar 14, 2022

By T. Marcher, C. Mathiesen, M. Allende, S. Bauer

"A unique pumped hydro storage facility using the ocean as a lower reservoir, combined with solar PV to create consistent, clean power will be presented: the Espejo de Tarapacá Project is comprised of a 300 MW seawater pumped storage hydroelectric plant using the Pacific Ocean as its lower reservoir and an existing natural concavity at the desert as its upper reservoir. The plant site is located in Chile’s northern coast 90 km south of Iquique. The site is characterized by a rocky shoreline and about 600 m of flat terrain moving inland, with an abundance of rock outcrops, after which there is a steep 700 m cliff. The power house and all waterways will be underground. The main focus is to present the rocks being expected in the underground works. As one of the actual most tectonically active regions of the world the seismic activity is particularly relevant and will be outlined in the presentation. INTRODUCTION Valhalla Energy is an independent Chilean-owned power development company. It focuses on the development, ownership and operation of renewable power projects. Valhalla was founded in 2011 with the goal of developing Chile’s natural renewable energy resources and strategically diversifies the country’s energy matrix away from an overdependence on imported fossil fuels. Valhalla began developing pumped storage hydro projects to provide scalable, clean, competitive, and reliable electricity by combining Chile’s superior solar resources with the country’s unique and extensive coastline suitable for storage.The capacity for renewable energy supply is driven by two distinct and unique natural characteristics found in northern Chile: (1) the abundant and reliable solar irradiation in the Atacama Desert and (2) a coastal site that benefits from a steep cliff and a natural concavity both within a relatively small land mass (see Figure 1). There are several potential sites in the northern part of the country that can be developed. The “Espejo de Tarapacá Project” is the first one to be built and subject of the present paper."

Jan 1, 2016

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 Ralph C. Flow

In Cleveland County, North Carolina, one and one-half miles south of Kings Mountain, Foote Mineral Company operates an open pit for the production of spodumene, feldspar, mica, and commercial stone. Spodumene concentrate is sent to Footers Sunbright, Virginia plant and to other customers. Exton, Pennsylvania and New Johnsonville, Tennessee plants produce lithium compounds sold to the oil industry for multipurpose lithium-base greases, to the metal industry as welding flux, to the air conditioning market, and to the glass industry. Ceramic grade spodumene, feldspar, and mica concentrates go to other processing companies from the Kings Mountain plant. Waste amphibolite is delivered to a neighboring quarry operation.

Jan 1, 1962

By Turan Uysal, Ramazan Aydogmus, MURAT ERDEMOGLU

The paper investigates the effects of calcination for thermal activation and intensive milling for mechanical activation on aluminum recovery by acid leaching of pyrophyllite ore enriched via attrition scrubbing and froth flotation. The study compares these methods in terms of energy consumption and aluminum recovery, concluding that mechanical activation is more economical and environmentally friendly.

Nov 1, 2023

By C. Villa Diniz

It is proposed that battery grade Mn02 can be produced directly from a manganese ore from Azul Mine in Brazil, by leaching with HCI to remove heavy metals selectively. We are working to find a way of selectively separating Cu, Ni, Co, Pb and Fe from the resulting acidic manganese chloride solution, to detoxify it and produce marketable chloride solution. Chelating ion exchange resins are proving more promising for this separation than solvent extraction with commercially available reagents. Results from batch and column ion exchange tests that characterize the behavior of copper, nickel, cobalt, lead and iron are reported.

Jan 1, 1999

By B. V. Cooper

The word "research" has been used in the title of my presentation somewhat against my better judgement. There are many definitions of the word. But the one I like best comes from Webster's New World Dictionary. It reads: "Careful, systematic, patient study and investigation in some field of knowledge, undertaken to discover or establish facts or principles. ..." I like that. In only 9 words, the definition conveys to me the very essence of what should be going on either in or for the coal industry. Unfortunately, not enough coal-related research is going on. And much of what is being done is, in my view, not really as effective as it might be.

Jan 1, 1983

By S. Garcia

The Minera Yanacocha operation presents various operating challenges, due to the complex structure of several heaps interconnected with ponds and gold recovery plants. A comprehensive process model has been developed in order to better understand the effects of certain operating parameters on issues such as water usage and inventory. An integral component of the water/mass balance of the process is a model of each heap that describes the flow and chemical behavior based on the individual characteristics of the heap. A computational fluid dynamic (CFD) software framework is used to model the individual heaps. The structure, calibration and validation of the model are described. Several examples demonstrating application of the process heap model are presented for the La Quinua heap. The effects of loss of solution flow to the heap (i.e., pump failure), increased cyanide levels in applied solutions and higher copper head grades on the process operation and balance are investigated with model simulations and compared to the baseline operating conditions. An example of estimating gold production and inventory based on projected heap loading plans is provided.

Jan 1, 2010

By S. D. F. Rocha, A. L. A. SANTOS, E. M. A. BECHELENI, R. M. Papini, P. R. M. Viana, F. P. C. Silvas

The kinetics of atmospheric sulfuric acid leaching from a Brazilian nickel laterite ore was assessed using distinct reducing agents and ore mineralogy. This transitional ore contains 1.63% Ni distributed as 1.27% in coarse size (− 500 + 150 μm), mainly as silicates (lizardite and chlorite—28.6%), and 2.06%in the fines fraction (− 75 μm), mainly as iron oxy-hydroxides (goethite and hematite—49%). The effects of temperature, acid concentration, reducing reagent type, and concentration were evaluated. The − 75 μm fraction limited the leaching efficiency and the use of reducing media with thiosulfate improved leaching and Ni-Fe selectivity. However, at constant Eh of 626–743 mV and a pH range between 0.2 and 1.1, no substantial rise in metals extraction, except for Co and Mn, has been observed. In order to determine the process control at 95 °C, two regions in the extraction curves were used in combination with the shrinking core model. Control by porous diffusion was observed and the kinetic constant was found to be in the order kFe<kNi<kMn<kCo<kMg for atmospheric leaching without Eh control. In reducing media for the first 15 min of leaching, the kinetic constant was found to be kFe<kNi<kMg≅kCo<kMn as derived from Ni disseminated into iron oxides structures.

Oct 7, 2020

By S. S. SHINDE, P. C. JIKAR, N. B. DHOKEY

Mill scale is an oxide waste product of the steel mills, which contains around 70% iron and other allied impurities. In the present context, a dynamic prototype counter current reactor (CCR) has been used for experimentation and simulation of particle bed by using discrete element method (DEM). Mill scale was pulverized to ASTM mesh range 140 (106 μm)/ + 270 (53 μm), and then it was oxidized in CCR to make single oxide Fe2O3 phase by maintaining required thermodynamic conditions such as pure oxygen at 1100 °C. Then this oxidized powder was subjected to reduction reaction in CCR having gas mixture ( H2:N2) ratio of 1:4 at 875 ± 5 °C for filling degree (fd) and reactor revolution (ω) ranging from 5.38 to 16.14% and 2 to 5 rpm, respectively. A creeping fluid flow condition (Re ˂ 1) and natural heat convection (Gr/Re2 ˃˃ 1) has been maintained while undergoing solid–gas reaction. Besides particle bed behavior has been quantified by Froude number (Fr) for the optimum operating window. The simulation was validated by the experimental results of reactor reaction product by X-ray diffraction (XRD) and scanning electron microscope (SEM) images. Prevailing heat transfer mechanism and reduction reaction mechanism has been established for solid–gas counter current conditions.

Nov 22, 2021

By K. F. Unrug

Martin County Coal Corporation is located in Martin County, Kentucky in the Appalachian coal fields, near the West Virginia border. The total leasehold covers more than 33 000 acres. Total annual production at Martin County Coal Corporation is currently 2,500,000 tons, but in certain years exceeded 3,000,000 tons. Approximately 45 percent of the annual production comes from two surface mines. The balance is produced from five underground mines. Martin County Coal Corporation&apos;s work schedule consists of 240 days/year, two nine-hours shifts/day.

Jan 1, 1991

By John S. Brock

During 1964 and 1965 a mineral exploration program was carried out over an area of approximately 250 square miles, located in the Anvil-Vangorda Creek area of east central Yukon, 125 miles northwest of Whitehorse. The Vangorda deposit, a massive lead-zinc sulphide body discovered in 1953, was centred in the area proposed for exploration, a northwest trending belt located between the southwestern flank of the Anvil Range and Pelly River. Exploration for base metals in the remote Anvil area had previously been restricted by poor metal markets in the late 1950&apos;s. Regional geologic information was also limited except for publication of a scale 1 inch to 4 mile map by the Geological Survey of Canada in 1961. To effectively explore this area, a combination of geophysical and geochemical methods were essential due to extensive overburden cover varying in depth from a few feet to over 300 feet. (Figure (i) Key Map) Dynasty Explorations initiated the first comprehensive regional exploration program in the Anvil area, utilizing saturation prospecting methods employing geologic, geochemical and geophysical methods. The program involved an approach demanding continual modification of technical and physical logistics. After a total of 12 months of field work involving an expenditure of approximately $450,00, massive sulphides were discovered which subsequently proved to be an economic orebody. Thirteen properties had been acquired and explored. Ten separate geophysical anomalies had been outlined by a combination of magnetic, electric and gravimetric survey techniques of which five were tested by rotary drilling and two by diamond core drilling. The discovery of the Faro deposit was a direct result of this program.

Jan 1, 1971

By F. W. Jessen

The production of salt through brining operations and the recovery of potash salts by means of solution with water constitute, in large measure, processes which have been used for many years. And although the salt industry has utilized dissolution techniques for years and years it has been only recently that a better understanding of the mechanism of solution has emerged. Greater adaptability of solution mining processes for recovery of valuable salts from ore bodies found at greater and greater depth has resulted in increased adoption of such methods. Because of the high costs of mining in beds of limited thickness, modifications probable when extracting mixed halites, and restrictions (mostly self-imposed) regarding the extent of cavern development to minimize or eliminate subsidence more information is needed on the solution mechanism. It is the purpose of this paper to present the fundamental aspects of the problem of total solution of salts and to point out the developments of certain solution mining techniques.

Jan 1, 1971

By Yohan Cha, Eun-soo Hong, Gye-Chun Cho

"Rapid population growth and scarcity of space have led many developed cities to bury supply facilities. In line with this, utility tunnels have been employed in Korea since the 1970s. However, approximately 70% of structures were installed more than 20 years ago, in response to the issue of ageing, tunnel enlargement has been proposed. The aim of this study is to investigate geo-mechanical behavior due to tunnel enlargement. Tunnel enlargement methods have been researched to suggest a optimal method. A finite element analysis is conducted to evaluate ground behavior by the expansion of internal space. Vertical displacement and settlement trough width are investigated according to ground stiffness and different enlargement size. It was determined that displacement is affected by the enlargement size and ground stiffness. Based on the deformation results obtained from the numerical analysis, it is possible to predict ground behavior and stability upon tunnel enlargement. INTRODUCTION Various infrastructures such as electric lines, communication lines, gas pipes, and water pipes are jointly accommodated by utility tunnels. These utility tunnels improve the aesthetics of urban areas and help ensure stable supply. The first utility tunnel in Korea was adopted in 1978 and new tunnels are still being installed with the development of new suburb cities. Nevertheless, about 70% of the utility tunnels were installed over 20 years ago and they are still being used through ongoing repair. Moreover, 90% of utility tunnels were installed before 1995. With aging of the nation’s utility tunnels various problems such as concrete deterioration and scarcity of capacity have arisen. As solution, reconstruction has been considered. Reconstruction can enlarge space and improve the performance by replacing existing structures. For reconstruction, two routes have been proposed: underground excavation and cut and cover. In order to avoid traffic problems caused by road occupation and civil appeals during construction projects, underground excavation is the more attractive option. Tunnel enlargement methods have been classified (Seo et al., 2008; An et al 2013) and major considerations during tunnel enlargement have been outlined (Beak et al., 2007). Enlargement construction cases on road tunnels around the world were introduced (Kim et al., 2012) and the deformation curve during tunnel expansion was proposed to investigate the range of protection that should be offered (Kim et al., 2008; Beak et al., 2011). However, tunnel enlargement technology is limited to road tunnels and railway tunnels. Hence, a study on shallow box tunnel enlargement is required for practical application."

Jan 1, 2016

By Brian Y. Lattimer, Kray D. Luxbacher, Jonathan L. Hodges, Manuel J. Barros-Daza

The abstract discusses the importance of predicting fire response time (the time before conditions become untenable for firefighters) in underground coal mines. It introduces a data-driven approach using artificial neural networks (ANNs) to predict response time and fire size based on measurable parameters like CO concentration, mine geometry, air velocity, and time since fire detection. The approach was tested using simulations from fire models (FDS and FSSIM), showing promising results for real-time predictions during mine fires.

Mar 6, 2022

By Tim M. Benson, Adam L. Lamanna, Carolina Martinez-Gutierrez, Mark J. Stephani

The Lower Concourse C Extension (LCE) 108-in Storm Sewer consists of a 2,797-foot long, 27 to 55-foot deep, 108-in I.D. storm sewer tunnel. Situated beneath active taxiways and a terminal apron at Hare International Airport (D), the tunnel diverts ows from existing storm sewers located within the footprint of a future satellite concourse. The project was delivered via Construction Manager at Risk (CMAR) as part of Chicago Department of Aviation’s (CDA) ongoing O’Hare 21 Capital Program. This paper presents project details, multiple stakeholder coordination, subsurface risks and challenges, TBM performance, and impacts to existing infrastructure.

Jun 23, 2024

By J. J. Reilly

The Vesta Mines of the Jones & Laughlin Steel Corporation operate in the Pittsburgh Seam in Washington County, Pennsylvania. This seam is overlain with a drawslate, 12" to 16" in thickness, which slimes readily when wet. Because of the need for a uniformly good quality metallurgical coal, the amount of reject, together with the top and particle sizes of the raw coal feed, is a serious problem at the Vesta Preparation Plant. The Preparation Plant operates two, seven and one-quarter hour shifts per day and processes 2,100 tons per hour of raw coal feed. The third shift is, used for planned maintenance of equipment. Since the water clarification equipment is so vital in insuring a uniform product, there is no alternative but that it be in operation at all times. To insure this continuous operation,. well-planned maintenance is a necessity. For years, Plant Management has kept performance records of the various units to determine the renewal dates of vital component parts, the length of wear, the various materials used in the manufacture of the equipment, and the labor cost for renewal. These records have been of inestimable help in planning an effective maintenance program to insure continuous operation of the various units.

Jan 1, 1959

By K. F. Unrug

The identification of the major subsidence areas in the Western Kentucky Coal Field has been made to distinguish the subsidence phenomena on the basis of geographical location Further, this identification process is based upon selected critical geological, topographical, and mining features in the coal fields. The proposed identification of the regions is derived from a comparison of the subsidence potential in a particular area. The most likely severe subsidence areas are compared to those with the probable low subsidence severity. The combination of certain geological and mining parameters involved allows for the derivation of a classification of the subsidence potential. It is recommended that further site specific studies should be performed on this area.

Jan 1, 1986

By H. R. Manouchehri

"Pyrrhotite (Po) is one of the most abundant sulfide minerals in processing industry and must be rejected in most cases. Particularly, Po rejection and its selectivity against pentlandite (Pn) have long been a challenge due to similarities in the mineral composition of the two minerals and the collectorless flotation characteristics of Po. Xanthates have been widely used to promote sulfide mineral flotation; however, in the presence of xanthates, the redox potential established at the mineral/solution interface is most important, determining the flotation performance. In this paper, the importance of electrochemistry in Po and Pn flotation has been demonstrated and a comprehensive study was conducted on two different feed streams (i.e., magnetic concentrate and scavenger cleaner streams, containing magnetic and nonmagnetic forms of Po, respectively), from Vale’s Clarabelle Mill in Sudbury, Ontario, with an objective to determine if improvements in Po rejection and Pn recovery could be achieved by controlling pulp electrochemistry. By conducting a series of flotation tests under different Eh conditions and reagent usage schemes, it was revealed that higher Po content in the magnetic stream may protect Pn from being oxidized, improving Pn recovery. The results indicated that at low oxidizing pulp chemistry, the rest potential for the Pn is still high enough to allow the formation of dixanthogen to promote its flotation. Using a Pt electrode, it was found that by controlling pulp potential at -50<Eh< +50 mV, the Pn recovery and Po depression would be satisfactory. The results, using mineral electrodes (Outotec Chena analyzer), indicated that selective separation can be achieved if low-to-moderate oxidation potentials (0 to 100 mV) or reduction (0 to -100 mV) potentials are monitored using Pn and Po electrodes. Mixing two streams at 50:50 wt % would be possibly beneficial in selective separation.IntroductionPyrrhotite (Po), Fe1-xS, is one of the most abundant sulfide minerals in the processing industry. It is an iron-deficient sulfide that occurs either in monoclinic or hexagonal form. The monoclinic one is richer in sulfur and is ferromagnetic, whereas the hexagonal Po is poorer in sulfur and has no magnetic properties. In general, the ferromagnetic properties of natural Po increase with increasing sulfur content. Although Po holds significant iron content, it is not used as a feedstock for the iron and steel industry due to the difficulty in achieving complete removal of sulfur. The common availability of iron oxide ores makes the iron sulfides irrelevant for the steel industry."

Jan 1, 2015

By R. Stefanko

Rock bolting as a method of support continues to increase with applications in many other industries in addition to mining. Nevertheless, with nearly 55,000,000 roof bolts installed in coal mines alone last year, this remains as the single greatest use. While bolts have frequently supported ground where conventional timbering could not, there are relatively few design criteria; and trial-and-error procedures prevail. Furthermore, development of suitable instrumentation that is simple to install and readout, sensitive, durable, reliable, safe and economical in evaluating the effectiveness of a bolt over long periods of time lags behind. Therefore, the pull test continues to be the most popular method of evaluating the applicability of a certain type of roof bolt under specific installation conditions. At Penn State in the Department of Mining, research has been conducted for a number of years to measure bleedoff in carefully controlled laboratory experiments as well as in underground investigations.1,2,3,4 Unfortunately, most of the instrumentation developed has been primarily suitable only for research purposes, not possessing all of the aforementioned characteristics desirable for routine underground use. Other groups also have met with restricted success. Therefore, while relatively crude, the torque wrench continues to remain as the most widely used load measuring device. While both field and laboratory tests continue to be conducted, analytical analyses are attempted to discover the more important design parameters in order that more efficient anchorage might be devised.

Jan 1, 1969