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By D. C. Seidel

The role of surface charge in soluble salt flotation, which was developed in Part 1, is extended to relate the theory to the specific phenomena of KCI- NaCl separations. Temperature-collector solubility relationships, metal ion activation, and particle size effects are discussed.

Jan 1, 1967

By P. S. Sundar

A laboratory method for the simulation of in-situ leaching of uranium was developed under contract to the Interior Department's Bureau of Mines. Simulation tests using sulfuric acid, ammonium bicarbonate and sodium carbonate as reagents and hydrogen peroxide as oxidant were carried out with representative ores from Texas and Wyoming. The tests not only yielded recovery rates of uranium and permeability changes, but also qualitative inferences on the chemical and physical phenomena which occur underground. Leaching with basic solutions was found to be kinetic constrained and with acid solutions, equilibrium constrained. The rapid permeability changes observed when leach solutions were introduced, were probably caused by gas blockages in the packing. Precipitation of calcite or gypsum and the reaction of clay to leach solutions had slow and gradual effect on the packing permeabilities.

Jan 1, 1978

By John D. Morgan

The United States is the world's most productive nation and its citizens enjoy one of the highest material standards of living of any people in the world. Materials and energy are the lifeblood of any industrialized economy. Annually the United States uses over 4 billion tons of mineral materials and fuels, or 40,000 pounds per person as detailed in Figure 1. Domestic processed materials of mineral origin and energy are valued at more than $150 billion annually, and they are derived largely from domestic sources, supplemented by imports, as detailed in Figure 2. In recent years the superior productivity of the United States has also enabled it to give food and manufactured articles to many other less fortunate nations and peoples of the earth. What then is our concern with materials at this time? Seeing the burgeoning increases in our mineral demand: from 2 billion tons in 1950, to over 4 billion tons today, and projected to 11 billion tons by 2000 - we are getting questions concerning our ability to continue to increase production sufficiently for the future.

Jan 1, 1974

By Simón Díaz‑Quezada, Ernesto Arancibia, HUMBERTO ESTAY, Tomás Vargas

In situ leaching (ISL) is an attractive technique that enables copper recovery from copper oxide ores that are either low-grade or located at depths too great to be economically exploited through conventional methods. At present, in situ leaching (ISL) has been applied to intact copper oxide ores, in particular, those which (i) present a good natural permeability and (ii) do not require preconditioning. Many copper oxide ores present low natural permeability. These are located above the water table and need preconditioning for the ISL application. The present work shows an economic assessment of the application of ISL to this type of copper ores. The preconditioning technique considered here involves the application of partial mining by sublevel stoping by removing a small fraction of the ore. This technique results in forming an ore bed with good permeability and good solution collection at the stope base. The economic assessment of this approach suggests that it can be implemented with positive net present values to copper oxide ores located at depths in the 100–300 m range, with copper grades above 0.4%. The maximum acid consumption values are below 52.5 kg/t, with blasting procedures designed to produce an ore bed with an average particle size below 6″. The breakdown of operational costs indicates that the mining cost is still very high, accounting for up to 60% of the total operating costs. Therefore, optimizing mining procedures is still necessary for improving the economic outlook of this approach and thus expanding the application field of ISL.

Feb 4, 2023

By J. A. Luppens

Five years ago, Phillips Coal Company decided replacing mainframe/workstation programs with a new package of PC software was clearly the best solution for computer reserve modelling. The system chosen was actually three programs distinguished by their power, cost, flexibility and integration, and ease of learning and use. Phase I involves the use of the "StratiFact" program for borehole data management and seam correlation. This phase is probably the most neglected, yet critical aspect of reserve evaluation. Phase II employs the "PC/Cores" package for modelling and volumetrics. Phase m is "PC-Cut" which provides mine planning tools including an automated cut generator.

Jan 1, 1996

By Adam Bezuijen, Tiago Gerheim Souza Dias

"The construction of mechanized tunnels in soft ground has evolved significantly over the last 20 years, especially in the control of the face pressure and the closure of the soil-lining void to reduce the induced settlements. On the other hand, several mechanisms of the TBM excavation cycle are still not taken into account for routine design calculations, such as the increment of water pressures in front of the tunnel face, the flow of excavation fluids around the shield, the dynamic equilibrium between the grout pressures and the excavation convergence, among others. This paper discusses specifically the issue of face pressures and how several mechanisms, which are routinely not considered, can be easily verified and incorporated into the state-of-practice of design. INTRODUCTION The stability of underground excavations is traditionally assessed through analytical solutions based on the lower bound theorem of plasticity (Atkinson and Potts 1977; Mühlhaus 1985) or the limit equilibrium method (Anagnostou and Kovári 1994; Messerli et al. 2010). These methodologies depend on the tunnel geometry, certain ground parameters and the support pressure. When conventional construction methods are used, the internal support pressure is an abstract representation of the combined effects of partial excavation, ground reinforcement, and the different support elements. The use of closed-face tunnel boring machines (TBM) changed this perspective, as the magnitude of pressures acting on the excavation boundary could be controlled in a more direct way. In front of the TBM the ground is excavated as the cutterhead rotates and the cutting tools scrape the ground from the tunnel face while additives are injected to condition the material. Water, polymers, bentonite, and foam can be used as additives under different conditions (Thewes et al. 2012). The loosened ground with additives, herein referred to as the mixture, flows through the openings at the cutterhead and into the excavation chamber. This mixture is kept pressurized to support the face."

Jan 1, 2016

By T. Braun, J. Parker

On June 25, 1999, BHP Billiton (BHPB) announced the suspension of operations at the BHP Copper Inc.(BHP) San Manuel copper mine in Pinal County, Arizona. Subsequent to this announcement, BHPB aggressively pursued a number of alternatives for the underground mine and open pit facilities, including continued curtailed operations, sale to a qualified mining operator and closure of the property. After consideration of these various alternatives over a 2.5-year period, BHPB announced final closure of the mine site on January 15, 2002.This paper describes how the BHPB charter and HSEC policy apply during the closure process.

Jan 1, 2004

By G. J. Goldberg

Through the early 1980's, surveying at Bingham Canyon required a great deal of repetitive and manual work. The advent of total station surveying equipment provided an opportunity to improve the speed and accuracy of surveying work while reducing manpower needs. An evaluation of total station systems and their ability to meet the surveying requirements of Bingham Canyon culminated in the purchase of a total station system as the mine re-opened in 1986. This paper presents the procedure for evaluating, implementing and using the total station survey system at Bingham Canyon.

Jan 1, 1990

By Jeff Easton, J Johnson, D. Foot

The Mina Santa Rosa mine in Panama was the victim of a mine closure 24 years ago that left the community in dire straits. The mine showed the potential resources of greater than 1M ounces of gold and 4.5M ounces of silver. Veragold Mining Company decided to reopen the mine and address all the issues that were involved in the startup of an historic mine. This paper provides methods to restore the community trust, provide a transparent process, and develop an environmentally sound flowsheet. Immense scrutiny surrounded the Tailings Storage Facility, and the company developed a plan focused on paste thickening and surface stacking to eliminate the need for a conventional tailings’ facility. Paste thickener principles and benefits are also provided.

Feb 1, 2024

By M. Zaske, E. R. Mortensen

"As mine operators continuously look for ways to improve functionality and increase the capacity of their facilities, existing process equipment is often pushed to and past its designed limitations. As a result, equipment manufacturers are asked for economical solutions to meet redefined processing needs. Newmont Mining in Nevada was faced with such a need in its carbon-in-leach (CIL) train. In a collaborative effort between Newmont and Derrick Corp., tests were conceived to assess the viability of drop-in replacement screens using a three-dimensional screen panel. The synthetic pyramid screen panel was designed to increase flux while maintaining the existing equipment footprint. The test is the end result of an ongoing research and development project that Derrick undertook in an effort to refine and upgrade its urethane screening media. The application of this new screening media is presented for this CIL application along with future plans to implement the technology in trash, safety, carbon dewatering, carbon sizing and other scalping applications.In spring 2014, Process Machinery Associates (PMA), Derrick’s local area representative, met with Newmont to discuss the operation of the in tank screens in the CIL train at Twin Creeks, near Golconda, NV. The process was originally designed for about 12+ kt/d (13,000+ stpd) but the throughput has been steadily rising since the plant was commissioned. Newmont now requires 14.5 kt/d (16,000 stpd) to be processed. The original screens were running at their maximum capacity, and Newmont required additional screening capacity to continue the upward trend in production.Physical separation by use of screening is one of mineral processing’s oldest methods. Screening media can be prone to blinding and pegging, and the necessary support structures required for finer apertures result in smaller open areas. Therefore, more screening area generally requires larger panels and, thus, larger machines, screening media that does not blind or a combination of both.In an effort to avoid larger machines, Derrick had been working on a revolutionary threedimensional panel that would add nonblinding screen area in the same footprint of an existing machine. Alpha testing of the new screen panels began at Newmont Mill 2/5 in July of 2013. It was still occurring when PMA approached Twin Creeks about beta testing a refined machine and pyramid panel. After presenting the initial results, Twin Creeks determined that an upgraded machine and pyramid panels would be a possible solution to meet production needs. The testing of a machine eliminated the risk of capital costs to Newmont and provided Derrick the opportunity to obtain additional data."

Jan 1, 2015

By Mark G. Aylmore, Eric J. Grimsey

Anenopyrite, both pure and in some cases associated with pyrite, was laboratory roasted either isothermally or at a constant heating rate, at temperatures mainly between 723 and 923 K and under environments of air, sulfur dioxide, oxygen and argon, as well as S02/02/H20/N2 mixtures. The mineralogy, arsenic contents and in some cases surface areas of the calcines were evaluated so as to provide an enhanced understanding particularly of the conditions under which the important transformations to pyrrhotite and magnetite occur. A thermodynamic analysis is also undertaken to rationalize the observations and provide some guidance for the operation of commercial roasters.

Jan 1, 1990

By Dan Brunner, Scott Thomson, Ben Lyddall, Duncan Thomson

Geosensing is used in oilfield drilling in conjunction with geophysical tools to support characterization of rock properties, geology, and reservoir conditions. This technology is now available to the mining industry and has been successfully applied to underground in-seam directional drilling in Australian coal mines for geologic exploration and methane drainage. The system utilizes a range of drill rig and wellhead mounted sensors which, combined with analytical software, produce real-time data from which 3D spatial features can be accurately modelled significantly in advance of mining. This innovation greatly expands on the information obtained from current in-seam directional drilling practices and provides for improved characterization of coal seams, including soft and weak zones, locations of geologic discontinuities, and analysis of formation flow. This paper provides a description of the geosensing system and the interpretation of actual data from long in-seam directionally drilled methane drainage boreholes at mines in Australia, and discusses how this system increases the value of directional drilling as an exploration tool for the coal mining sector, and the evaporite and hard-rock mining sectors where directional drilling is also applied.

Feb 1, 2024

By Nicole R. Henderson

Many mining engineering graduates enter the mining industry lacking training in mine emergency management. As a result, mining universities in the United Sates and other countries are beginning to form volunteer student mine rescue teams to train mining engineering students in handling mine emergency situations and give them hands-on experience managing potential emergency scenarios underground. In the early 1980s, the Missouri University of Science and Technology developed the first collegiate mine rescue team in the United States. For approximately 30 years, it was the only successful collegiate team until the Colorado School of Mines (CSM) started its program in 2009. Currently, there are at least five collegiate teams in the United States and one in Canada. At the Freiberg University of Mining and Technology in Germany, the goal is to adapt the Colorado School of Mines Mine Rescue Program to develop a collegiate team of its own. Currently, mining engineering students cover the theoretical basics of mine rescue in an occupational health and safety lecture and take a basic, one-day mine rescue training course at the Central Mine Rescue Station in Leipzig. The course covers the basic mine rescue topics and gives students the opportunity to experience working in elevated heat and smoke conditions while wearing breathing apparatus. This training gives students a small insight into the importance of mine rescue and mine emergency management. Collegiate mine rescue teaches students the importance of mine rescue and mine safety by giving them hands-on learning experiences before entering the mining industry.

Feb 1, 2014

By Ying Lu, Jeffrey C. Johnson, Chen-Luh Lin, Jan D. Miller, Sindhoora Puvvada

Energy dissipation and fragmentation of rock is of interest for mine-to-mill operations in order to understand breakage and to minimize energy consumption during blasting at the mine site, and comminution at the processing plant. In this regard, high velocity impact breakage of long granite cores, called bars, has been studied with instrumented strain gages to follow the energy dissipation gradient along the bar length resulting from the strain waves generated by impact. As a result of high velocity impact, three zones have been identified (fragmentation, fracture, and elastic) and these three zones have been characterized in 3D using X-ray tomography. The fragmentation zones of the granite bars were studied in detail to describe the particle size distribution and the particle shape characteristics. Finally, the experimental energy dissipation for the fragmentation zone was found to be in close agreement with the expected energy calculated from the Bond work equation, if the anisotropic granite particles are defined by length rather than by sieve size.

By Mary Nelima Ondiaka, Kayode Henry Talabi, Oladunni Oyelola Alabi, Fatai Olufemi Aramide, Francis Gitau

Iron ore is essential in steel making; however, high-grade ores have diminished, making low-grade ores inevitable. These lowgrade iron ores need further beneficiation to upgrade the iron content. Currently, traditional physical and chemical methods are utilized and are not environmentally friendly. Bio-beneficiation techniques have emerged as a sustainable alternative for mineral recovery. This review delves into recent bio-beneficiation advancements for enhanced low-grade iron ore recovery using microbes. Research has revealed that bio-beneficiation methods such as bio-leaching, bio-flotation, and bio-flocculation have proven successful in iron recovery from ores. The bio-beneficiation process occurs in mild conditions using bio-reagents derived from microbes and offers a reduction of chemicals used in processing. Bio-beneficiation of iron ore potentially offers a relatively energy-efficient, cost-effective, and environmentally friendly method of maximum iron ore recovery. However, this review has identified a scaling-up difficulty in which a future approach for industrial-use applications is offered following a thorough sustainability assessment. Bio-beneficiation, using microbial processes, provides a viable avenue for maximizing iron ore recovery while tackling the constraints of dwindling high-grade iron ore resources and environmental sustainability.

Mar 16, 2024

By Hisashi Takahasi, Hironobu Yamazaki

INTRODUCTION The slurry shield method was developed in Japan in 1963 and its experimental tunnelling work was performed in 1965. Although the history of this method is short compared with the conventional shield method in Japan, many companies such as Tekken Construction, Okumura Gumi, Nishimatsu Kensetsu, etc. are engaged at present in developing their own unique system of the slurry shield method. The ground of Japan is generally pervaded with ground water and a large number of districts are covered with soft ground, which is composed of fine sand, silt and clay, etc. Therefore, the conventional shield method has always used compressed air with various kinds of auxiliary methods. However, with this method there have been experienced numerous troubles such as ground settlements, lowering of ground water, oxygen shortage within the tunnel, and so forth. The slurry shield method has been developed with the above background. In recent years remarkable progress has been made from the engineering viewpoint in applying this method to driving various kinds of tunnels such as road tunnels, subways, water supply and sewer tunnels, and other tunnels. Apart from Japan, the slurry shield process using bentonite is carried out in England and Germany. OUTLINE OF SLURRY SHIELD METHOD (1) System of Slurry Shield Method Since the conventional shield method drives tunnels using com-

Jan 1, 1976

By S. E. Phillipson

The Late Miocene San Cristobal Ag-Zn-Pb deposit represents syngenetic and epigenetic mineralization with low- and high-sulfidation characteristics. Geology is characterized by barren dacitic ring fracture domes, mineralized resurgent rhyodacite domes, strongly altered and mineralized tuffaceous lacustrine sedimentary rocks, and an extensive crystal-lithic tuff debris apron. The ore body is hosted by intra-cauldron sedimentary rocks and breccias. Fluid inclusions suggest that silver, lead, and zinc were transported as chloride complexes and precipitated by cooling in veins from <5 wt. % NaCl eq. fluids at 170°-215° C. Silver associated with resurgent rhyodacite was transported as a chloride complex and precipitated by increased H2S activity or increased fluid pH.

Jan 1, 2001

By J. C. Mullen

Today, the coal mining industry is more knowledgeable on the potential negative economic consequences associated with improper management of hazardous substances and various types of solid waste. The practices evaluated during environ-mental audits are discussed and example situations are shared from previous audits of coal mines and analogous situations. The importance of assessing and understanding purchasing, warehousing, safety, maintenance, electrical, operations, and environmental management practices and procedures is highlighted as a key to a successful and practical program. A waste minimization approach is presented including strategies for screening product purchases, product substitutions, and testing and record keeping.

Jan 1, 1992

By Jorge A. Benitez Muro

Within the exploration programs carried on by the Consejo de Recursos Naturales No Renovables, the one with the largest coverage (more than 75, 000 square kilometers) is the northern Coahuila Exploration Project. Due to its nature, geochemical exploration methods were selected to obtain quick results. The program included essentially, three main stages : 1. - A regional geochemical stream sediment survey. 2. - Semi-detailed studies of the anomalous areas selected in the previous stage, and 3. - Detailed exploration of the promising areas. To the date, the first two stages have been completed, and the third one is being carried on. The work was started on september 1972, and it will probably take one more year before drilling can be started, but at the end of stage three it is expected that at least 5 important targets will have been detected. The regional work was conducted by 3 field crews, but the detailed program is being done by only one.

Jan 1, 1974

Slurry technology developed for the marine transport of mineral commodities has been increasingly applied to on-shore slurry transport systems. Reclaim of mineral concentrates, sand tailings for mine backfill and various industrial minerals from storage tanks or ponds normally require a slurry of high density at constant flow rates to improve process performance and to reduce handling costs. An efficient system must accomplish this at minimum capital costs with maximum reliability. Continuing improvements in equipment design to improve repulping efficiency and their application are discussed.

Jan 1, 1986