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By Francis Martino

Just as coal producing mines are faced with various handicaps which control the quantity of coal produced and sold, the subsequent user of that product is faced with parameters that impact the optimum utilization of coal. Traditionally, the industry focused on the quantity of mineable coal in a reserve. The mine planning development was primarily concerned with two important criteria: (1) safety and (2) the productive efficiency in a quest to produce the lowest cost coal.

Jan 1, 1982

By J. A. Jirestig

Laboratory investigations on the possibility for magnetic separation of sulphide minerals are reported. A survey of several sulphide ores and flotation concentrates shows that magnetic separation in most cases is not a suitable primary method of beneficiation. However encouraging results have been obtained in concentrate purification. At the Boliden complex sulphide ore concentrator in Garpenberg a Allis-SALA MK III carousel High Gradient Magnetic Separator (HGMS) is used together with a small flotation circuit to recover sphalerite lost to the galena concentrate in lead flotation. The result after four years of refining the HGMS process, show increasing zinc recovery and enhanced quality of the lead concentrate.

Jan 1, 1993

By Antti Porvali, Vivek Agarwal, Mari Lundström

Hydrometallurgical recovery of rare earth elements (REE) from NiMH battery waste can be performed using sulfuric acid leaching followed by selective precipitation as double salt (REENa(SO4)2·H2O) by adding Na2SO4 as a precipitating agent. The formed double salts can then be further converted with NaOH solution to form REE hydroxides. However, present literature has paid little attention to how to minimize the consumption of reagents in this recovery process. In the current study, a process model was built using HSC Sim software, and metamodeling of the simulated flowsheet was conducted with the design of experiments (DOE), after which the basic functionality of the flowsheet was verified by experimental work, starting from sulfuric acid leaching of spent batteries. As the process is based on chemical circulation internally in the process, the objective was to investigate the accumulation of the elements in solution, specifically Na+ , K+ , SO4 2− ions and impurities liberated in the NaOH conversion step. It was found out that metamodeling could be utilized in obtaining first estimate of the process behavior, prior to any experiments. Flowsheet functionality with circulated solution was confirmed, obtaining at best 96.9% La recovery.

By J. B. Webster

Health and Safety in the work place is of primary concern to the underground coal industry. Control of dust in the underground environment is of major importance in this concern. Utah Power and Light Mining Division has undertaken extensive studies to determine and control the various sources of respirable dust in underground high production sections. Determination of dust sources has been achieved by real-time aerosol sampling and standard gravimetric sampling on individuals and in various suspect locations. Some sources are diesel roadway dust, outby crushing, and handling equipment, face sloughing, water spray roll-back, and mining equipment. Once identified, the dust sources are suppressed or controlled and/or the workers are directed from areas of greatest potential exposure.

Jan 1, 1990

By William G. Pariseau

The purpose of this paper is to present a discussion of the various approaches that can be utilized in the study of mine subsidence phenomena. Attention is focused upon the rational selection and use of laboratory models. Broadly interpreted, mine subsidence is the deformation of the rock mass enclosing the mine. Depending upon a number of factors, the movement of the subsiding rock mass may be such as to disrupt gas and water lines or other buried utilities, to damage surface structures such as buildings and bridges, to dislocate streams, roads, and rail lines, to aggravate acid mine drainage and fire problems, and to generally mar the landscape. It is clearly a problem that no mine manager can safely ignore. It is also a problem that will grow with the general population increase. In the following, a summary review of past and present approaches to subsidence studies is given. The possibilities of duplicating subsidence phenomena in laboratory models are examined, and an analysis of a particular type of model is presented. Some preliminary results obtained from a model of the particular type analyzed are then discussed.

Jan 1, 1968

By Irina Chernyshova, Erik Larsen, Hanumantha Rao Kota, Vladislav Slabov, Garima Jain

The mining industry faces pressure to provide metals for the green digital shift using sustainable technologies. This study evaluates biosurfactants as collectors for ultrafine and coarser particles of hematite and malachite, aiming to improve the flotation of ultrafine particles.

Jun 1, 2023

By Jenny Alsén, Hans Hogard

"Construction of large facilities underground in urban areas has many advantages. In order to show the advantages, a case study of the Norsborg metro depot in Stockholm Sweden has been made. The Norsborg metro depot will be the largest and most modern underground metro depot in northern Europe. The depot has been built in hard rock in an urban area with small impact on the environment and local residents. The paper describes how it is possible to build underground facilities in a cost efficient way and take care of the challenges regarding working environment that comes with locating a permanent working place underground. INTRODUCTION The Stockholm area is one of the five fastest growing regions in Europe and home to more than a fifth of Sweden's population on just two percent of Sweden's surface. The population is growing rapidly, with about 35,000 people per year and is expected to reach 2.6 million in 2030. In order to meet the development and enable continued growth, housing projects and expansion of infrastructure need to keep the same pace; this is an easy conclusion to make but much more difficult to realize in practice. The main challenge is to accomplish development in a sustainable and efficient manner, minimizing the use of resources and land. By constructing facilities underground more urban space will be made available for development and/or for greening of city centers. Considering sustainability factors such as land value in decision making for placing of structures or facilities, underground locations could become a first choice alternative. During 2015 and 2016, several major underground infrastructure projects in the city of Stockholm will start, including a 14 km sewage tunnel and an 18 km by-pass highway tunnel. Furthermore the Stockholm metro system is currently undergoing the largest expansion since the 1970’s, a 19 kilometers extension of the metro system including new trains and new stations is planned. During 2013 - 2015 Skanska Sweden took part in the construction of a new metro depot placed underground in the southern part of Stockholm; the Norsborg metro depot. This is a top modern urban underground facility that in 2017 will serve as depot for 17 new metro trains. The project was selected for “Outstanding Project of The Year” at the ITA Tunneling Awards 2015."

Jan 1, 2016

By B. E. Davis

A problem that has continued to plague the Florida phosphate industry is the loss of coarse phosphate in the flotation circuit. Attempts to remedy this problem such as floating the coarse material (plus 425 µ m) in a separate circuit have resulted in limited success, but recovery is still not optimum. The Bureau of Mines is investigating ways to improve the recovery of coarse phosphate through improvements in the conditioning step. Studies to optimize conditioning parameters such as agitation energy, conditioning time, conditioner solids, and residual clay content have resulted in improved P2O5 recovery. Optimizing these and other conditioning parameters resulted in a rougher concentrate grading 30 pct P2O5 with a P2O5 recovery of 97 pct.

Jan 1, 1993

By Arif Emre Dursun

The aim of this study is to present hazard classifications of location, type and causes of accidents in the Turkish coal-extracting industry using the analytic hierarchy process (AHP). In this study, fatal mine accidents were analyzed by pairwise comparison and weighting, and the most important hazards were identified by determining the effective main and sub-criteria among location, type and causes of accidents. For this purpose, first-, second- and third-level hazards consisting of location, type and causes of accident were determined by using the data of fatal mine accidents in underground and openpit coal mining in Turkey between 2010 and 2020.

May 1, 2024

By Leonardo Rosas Sánchez, Darío Ángel Bulla

"The two track road sector between Cisneros-Loboguerrero (having a length of 14 km and 11 short unidirectional tunnels) is a new highway still on construction located along the existing Highway Buga – Buenaventura (Colombia). Due to the steep topography, difficult geological/geotechnical conditions, the traditional portal construction approach was impossible to be implemented in eleven (11) of the twenty two (22) portals. In this specific project, the skewed portal approach was developed as the optimal and more effective solution. The construction time and costs of portals were reduced in 21 months and 75%, respectively. At the same time, the natural equilibrium of the slopes was maintained, thus, facilitating adequate safety factors along the useful life of the project. This document pretends to show a detailed design experience (and the construction of the entry portal of tunnel 11 (left)). INTRODUCTION The Cisneros-Loboguerrero project is a 14 km length dual lane highway, connecting productive zones with the Pacific Ocean along the current Bogota-Buenaventura highway as shown in Figure 1. The project is located at the northern side of the Dagua River Valley. The preliminary design suggested constructing portals under challenging topographical conditions, i.e., slope cuts having heights between 50 to 100 m (some having slopes > 100%) requiring complex developments and having very high risks.The entry portal of tunnel 11 (left) was the first portal successfully built by implementing the skewed portal approach. Later, this approach was used as a model for the construction of the other ten (10) portal having similar topographic and geotechnical conditions. The development of this new alternative provided a considerable reduction on the construction time of portals, thus relieving a critical path in this project."

Jan 1, 2016

By Mark Alan Marlkos

Blebs of solid bitumen from the Magmont West orebody of the Viburnum Trend were examined and analyzed in an attempt to relate hydrocarbon distribution and origin to ore genesis. The bitumen was calculated to be approximately 48 to 63 percent aliphatic and is considered to be a polymerized normal crude oil. Polymerization, which was probably caused by water-washing, hardened the bleb surfaces and appears to have "frozen" the blebs during primary migration from local source beds. Comparison of the bitumen to kerogen in local shaly partings strongly Indicates that the oil was derived locally. The polymerized oil blebs are considered to have been derived from a type II (marine) kerogen. Textural analyses indicate that oil migration occurred after lead-zinc mineralization and at temperatures that exceed normal ancient or present geothermal gradients. The following sequence of events is postulated for the Magmont West orebody: 1 Generation of hydrogen sulfide during diagenesis of a normal organic-rich carbonate sequence. 2 Introduction of pulses of hot, metal-rich fluids that resulted in: a Lead-zinc mineralization by the following reaction: Me++ + H2S ? MeS + 2H+ b Solution of carbonates by excess acid produced during the above reaction. c Brecciation of host rock in some cases. 3 Passages of the pulse resulted in: a Carbonate buffering of fluid system to more alkaline conditions. b Precipitation of dolomite c Slight temperature drop. 4 Eventually the high temperatures Introduced by heated brine caused oil generation and initiated primary migration. 5 Water-washing and mild biodegradation altered the hydrocarbon blebs to their present composition.

Jan 1, 2013

By John D. Price

In the constant search for ways and means of improving the quality of coke and thus making its use at the blast-fornace more satisfactory and economical, it has become increasingly evident that the present laboratory tests do not show the full picture of a coke's value as a blast-furnace fuel. This fact was recognized by Dr. A. C. Pieldner thirty-five years ago: (Ref. 1) here is perhaps no phase of fuel technicology which has aroused more discussion or regarding which there is more difference of opinion than the properties of coke which make it most suitable for blast-furnaces and other uses." Dr. Fieldner followed this assertion with a statement to the effect that men who write on this subject today (1923) have, because of conflicting experimental evidence brought forth in recent years, far less positive opinions on the matter than did writers of some years past. One is led to wonder if these statements are not just as true now as they were when first made.

Jan 1, 1959

By Jon Ike Isaacson, Michael Miller, Jarek Trela

Despite reef structures being relatively common in carbonate rocks around the world, tunneling experience in reefs is extremely rare. Impacts and risks associated with reef tunneling through these geologic features were also relatively unknown. A new reef was encountered during construction of the Lower Pogues Run Tunnel in Indianapolis, exposed over 5,000 linear feet along the alignment, resulting in adverse impacts on construction. Analysis of investigation data and construction from this encounter provide insight into the identification and characterization of reefs along tunnel alignments as well as the potential impacts on construction for future tunneling within reef structures.

Jun 23, 2024

By Robert McIvor, Sami Makni, Andreia Rosa, Claude Gagnon

In response to the Natural Resources Canada “Crush It Challenge,” Corem partnered with the University of British Columbia and led a project to develop and demonstrate the use of high-pressure grinding to replace the workhorse of the industry, wet ball milling. Two plant case studies, a small tonnage gold recovery operation and a large tonnage copper recovery operation, were carried out. Plant circuit performances were compared to pilot plants operated on the same circuit feed setup to represent the novel equipment and flowsheet that was developed to produce separation circuit feed. Numerous obstacles to industrial implementation of high-pressure grinding in this role which were recognized at the outset of the work were successfully addressed. In both cases, comminution equipment energy savings alone and final stage total circuit energy savings exceeded 60% and 50%, respectively. Downstream mineral separation performance was the same or better.

Nov 28, 2023

By P. R. Taylor

Batch leaching experiments have been performed to study the kinetics of galena leaching in fluosilicic acid solutions with oxidants. Variables studied included: fluosilicic acid concentration, oxidant type, oxidant concentration, particle size and leaching temperature. It was found that hydrogen peroxide was the most effective oxidant, compared to the others studied, and the effect of the oxidant concentration on the leaching behavior of galena was very significant. Also, decreasing the particle size and increasing the leaching temperature increased the extraction rate. The initial, apparent activation energy was calculated to be 11.72 kJ/mole (2.8 kcal/mole) and suggested that galena leaching in fluosilicic acid solution, with hydrogen peroxide as an oxidant, may be controlled by fluid film mass transfer initially. The reaction appears to be retarded by the formation of elemental sulfur and the sulfur oxidation becomes a major resistance to the overall leaching reaction.

Jan 1, 1992

By L. M. Gochioco

The U.S. coal industry is under-going dramatic changes to meet the challenges of the keenly competitive fuels market. The application of innovative technologies is needed to improve safety and to increase productivity in order to make coal more competitive as a fuel. As more coal companies shift into capital intensive longwall mining, there is a clear need to invest more in exploration before mine plans are made. Coal seam anomalies may create adverse mining conditions. The early detection of these anomalies could make the longwall mining safer and more productive through improved planning. A standard exploratory drilling program can provide only limited geologic information. The seismic reflection technique can be used to detect coal seam anomalies and is effective in reconnaissance surveying. Recent advances in the quality of coal seismic data have increased the success rate of seismic surveying. Therefore, surface seismic surveys, coupled with selective drilling, will come to play an integral role in coal exploration in the 1990s.

Jan 1, 1990

By V. T. McLemore

New Mexico Bureau of Geology and Mineral Resources (NMBGMR) has been collecting data on uranium mining districts, mines and mills since it was created in 1927 and has converted years of historical data into a relational database that can be imported in ArcMap. The database includes information on mining districts, mines, mills and geochemistry, as well as photographs and bibliographic resources. The available data includes location, production, reserves, geologic, geochemical, resource potential and other data. The National Uranium Resource Evaluation (NURE) stream-sediment data provides geochemical analyses for >27,000 samples collected in New Mexico during the 1970s. The NURE hydrogeochemical data provides analyses of water samples. ArcMap includes the location of individual ore bodies as polygons and incorporates the mines and NURE data as individual site locations. The purposes of these databases are to provide computerized data that will aid in identifying and evaluating resource potential, resource development and management, production and possible environmental concerns, such as physical hazards (i.e., hazardous mine openings), indoor radon, regional exposure to radiation from the mines, background geochemical data and point sources of possible pollution in areas of known mineral deposits.

Jan 1, 2010

By M. Z. Rashad

The purpose of this work is to determine the influence of sample length or size on the value of variance (Semivariogram) to select the suitable length that is required to the geostatistical computations of ore evaluation. Three cases in Ghorabi Iron Ore were studied. The first one was on the iron fraction (Fe%) at which the semivariogram gave an evidence to good continuity of the fraction in the ore. In this case, the length of sample has not important influence. The second case was for the Mn% component of the same area where the semivariogram has a nugget effect. The selected length for this case was 4 meters. The Cl% fraction of the ore was the third case where the anisotropic phenomena was appeared and the suitable length is 3 meters.

Jan 1, 1992

By M. Z. Rashad

The purpose of this work is to determine the influence of sample length or size on the value of variance (Semi-variogram) to select the suitable length that is required to the geostatistical computations of ore evaluation. Three cases in Ghorabi Iron Ore were studied. The first one was on the iron fraction (Fe\) at which the semi-variogram gave an evidence to good continuity of the fraction in the ore. In this case, the length of sample has not important influence. The second case was for the Mn\ component of the same area where the semi-variogram has a nugget effect. The selected length for this case was 4 meters. The Cl fraction of the ore was the third case where the anisotropic phenomena was appeared and the suitable length is 3 meters.

Jan 1, 1992

By H. M. Brennecke

A new hydrometallurgical process has been developed to recover copper from sulfide ores. Copper is leached in a staged reactor system utilizing nitric and sulfuric acids at 105°C. Iron is removed from the pregnant liquor as a jarosite and cathode copper is electrowon directly from the purified pregnant liquor. The spent electrolyte is recycled. Nitrogen oxides evolved from the leach are reconverted to nitric acid and are also recycled. Sulfur is rejected as S°, jarosite and gypsum. The process is highly versatile and can recover precious metals, molybdenum and zinc, when these elements are present. Continuous, integrated, semi-pilot plant operations using chalcopyrite ores demonstrated 99% copper leaching and production of cathode grade copper. Economic evaluation shows that the process is competitive with pyrometallurgical and other hydrometallurgical processes.

Jan 1, 1978