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By Shangyong Lin, Wei Sun, Weiping Liu, Muhammad Azam, Junfeng Chen, Yujie Zhao, David Asubonteng, Michael Ngoie

Copper concentrates are widely used in smelting operations worldwide and typically consist of chalcopyrite ( CuFeS2) as the primary mineral, with chalcocite ( Cu2S) and bornite ( Cu5FeS4) as secondary copper-bearing minerals. However, these concentrates often contain hazardous impurities, such as the fluorine ion, which can result in various complications during the smelting process. These issues include equipment corrosion, gas treatment requirements, environmental hazards, and strained community relations. Furthermore, high fluorine content in copper concentrates can lead to penalties and limitations during sales. To address these challenges, this comprehensive review assesses current techniques for removing fluorine from copper concentrate. Drawing upon recent research and the findings in the field, the review analyzes the advantages and disadvantages of existing fluorine removal methods and identifies critical issues requiring attention in the future. This review provides valuable insights into the current state of fluorine removal from copper concentrates and serves as a practical guide for researchers and industry professionals in this field.

Aug 2, 2023

By Ronald G. Schmidt

AND SOME RIN UP HILL AND DOWN DALE, KNAPPING THE CHUCKY STANES TO PIECES WI' HAMMERS, LIKE SAE MANY ROAD MAKERS RUN DAFT. THEY SAY IT IS TO SEE HOW THE WARLD WAS MADE. Sir Walter Scott St. Ronan's Well - 1824 In the minds of many, geologic exploration has advanced little since the early nineteenth century. In truth, despite the development and refinement of new and potentially valuable technological tools, the approach or philosophy of the explorationist has received meager attention in professional literature. In many areas, the explorationist relies upon experience, subjective judgement and general intangible inspiration, often traveling together under the misleading pseudonym of "art," in achieving both an exploration plan and in making the myriad day to day decisions necessary to the execution of that plan. Without a solid, objective basis for decisions, exploration under this concept is little more than guesswork largely by intuition, and it is small wonder that many exploration programs flounder in a sea of over-expenditure inefficiency or fail to fulfill their expected goals within the funding which has been provided. From a rational management point of view, such a state of affairs is frustrating and inconsistent with the application of the same scientific principles which are presumed to be the basis for the exploration methods which are used. This somewhat presumptuous point of view cannot be extended as a general condemnation of the many exploration programs which are both technically and economically successful. On the other hand, the

Jan 1, 1968

By H. Hinds

Plant testing of DuPont's Activator Technology in the vat leach circuit of the Homestake mine shows increased gold recoveries of 3-5%. Activators are catalysts of gold dissolution in cyanide solution. DuPont received the patent for this technology in January, 1996. The test was run in the west sand plant alternating control and activated vats to reduce the variability in head grade and cyanide consumption. Activated vats had gold in the preg solutions earlier, higher gold recovery, and lower gold residuals. Activator addition did not adversely affect mill operations or the environment. Optimization of the technology continues.

Jan 1, 1997

By P. W. Conrad, C. Todd, N. West, R. Kramer

"Surface subsidence caused by both underground room-and-pillar mining operations and solution mining operations have each been studied separately, but never combined. In 2008, FMC Minerals began using solution mining at its Westvaco Mine as a secondary extraction method in an area that had been previously mined using the room-and-pillar mining method. Mining regulations require that subsidence associated with underground mining activities be monitored and measured annually. Researchers at Montana Tech were able to develop a relationship between measured surface mine subsidence and solution mining that can be used at the Westvaco Mine to estimate the production of trona from solution mining operations. PROJECT BACKGROUND FMC Minerals (FMC) has increased the production of trona from its Westvaco Mine near Green River, Wyoming, using solution mining as a secondary extraction method in an area previously mined using the room-and-pillar method. The area of interest was mined until 2001 with the use of a borer miner at a depth of approximately 1,600 feet. Currently, FMC determines the amount of trona produced using its solution mining operations by measuring the dissolved solids pumped from the mine. This approach, however, does not account for the location from which the trona was removed. The location from which the trona was removed and the size of the cavern created by the solution mining operations is important to FMC’s mine planning. FMC believed that with proper investigation of the subsidence at the Westvaco test site, a correlation might be found that would allow for the use of surface subsidence measurements to estimate the amount and location of trona production from the solution mining activities. The primary goal of this project, conducted by Montana Tech, was to find a relationship between the measured subsidence and the solution mining activities. The project attempted to model the relationship between the measured subsidence and the solution cavern using Salt_Subsid, an existing subsidence software package from the Solution Mining Research Institute (SMRI), to determine the program’s usefulness for locating and developing the cavern created by solution mining activities. The project also attempted to develop an equation that could be used to predict solution trona production based on measured subsidence. The data used in this study were collected over a seven year period, 2008 through 2014."

Jan 1, 2016

By Muhammad I. Kabir

The streamline method of recovery prediction reduces a two-dimensional problem to a bundle of one-dimensional ones. This paper presents the development and application of a novel scaling technique which, when used with a streamline model, causes s bundle of one-dimensional problems to further reduce to a single one-dimensional calculation. The one-dimensional calculation accounts for chemical-rock interactions and the streamline model for areal sweep. The scaling technique significantly reduces computation time, is readily modified to desk-top calculations, and can be applied to both absorbing and reacting species. The work was sponsored by the Interior Department's Bureau of Mines.

Jan 1, 1984

By J. W. Cooksley

Seismic methods provide an efficient and comprehensive approach to overburden studies pertinent to mining exploration and development, and to other mining and civil engineering problems such as rock mechanics, slope stability, and foundation engineering. For the purpose of defining geologic units and structural features, these methods are generally regarded as the most accurate, but most expensive, of the commonly-used geophysical exploration methods. Although the accuracy and cost of seismic work are generally affected adversely by rugged topography and complicated geologic conditions, it is in rough terrain and complex geology that seismic methods offer important advantages in overburden investigations. For example, to find the surface of rock underlying unconsolidated overburden at depths of approximately 200 feet, a 50-foot spacing of drill holes along the profile line would be required to yield a degree of resolution and accuracy similar to that obtained from a 50-foot spacing between seismic detectors along the same line. See Figure 1. In cases similar to that shown in Figure 1, a twelve-channel recording seismic system would be used. The main components of such a system would be: 1. detectors (commonly referred to as geophones) which convert the ground movement resulting from seismic waves into an electrical signal. 2. a multi-conductor cable which connects the seismic detectors to the amplifiers. 3. ampliiiers, amplify and filter the electrical signals . 4. oscillograph, records the amplified signal. 5. the blaster and firing line. A typical layout of the seismic spread and the components of the system Is shown in Figure 2.

Jan 1, 1968

By J. C. Franklin

The U.S. Department of the Interior, Bureau of Mines, has developed a data acquisition system to continuously monitor radon, working level, absolute pressure, temperature, relative humidity, and air velocity. Data have been taken in intake and exhaust drifts, working stopes, and sealed-off areas of positive and negative ventilated uranium mines. Radon emanation rates, ranging from 1.7- to 12.2 x 2 10-l4 Ci/cm /sec were determined in four mines. The ratios of short duration, primary fan shutdown time to radon normalization time were 1 to 2 and 1 to 4, respectively, for-negatively and positively ventilated mines. Blasting and slushing caused radon increases of 160 and 67 percent, respectively.

Jan 1, 1980

By K. T. Brashear

Since the MINER Act of 2006, the minimum static load of in-situ underground mine seals has been increased from 20-psi to either 50-psi if monitoring is conducted or 120-psi if left unmonitored. These minimum strength requirements in seals must be designed, built, and maintained throughout the lifetime of the seal. Due to this, it has become necessary to assess the effectiveness of non-destructive testing (NDT) technologies to determine seal integrity, which in this case, are explored using sonic waves and tracer gases. Through both small and large scale testing, two NDT methods will be evaluated for their abilities to determine integrity of the seal. A sonic wave technique to observe a change in wave velocity to identify faults within the seal material. As a NDT method, tracer gases may be used as a potential indicator of a connection between both sides of the seal material through a series of faults and cracks within the material itself. This paper reviews the history of underground mine seals and discusses the overall assessment of sonic waves and tracer gases to serve as NDT methods for estimating the integrity of these seals.

Feb 23, 2014

By David Humphreys

Assumptions about future commodity prices need to be made with close regard to the purposes for which they are being used. Prices generated for financial planning or trading purposes are unlikely to be suitable for the longer run purposes of project evaluation and reserve estimation. In this latter context, price assumptions need to be realistic, stable and rooted in a rigorous fundamental analysis of long run industry drivers. Amongst the factors to be considered in such analysis are price history, production costs and structural dynamics. It is also important that prices adopted are consistent with other information being used by a company in its decision-making.

Jan 1, 2003

By Foreback T. G.

The McKinley Mine is a large strip operation sup-plying coal to several utility and industrial customers. The mine reserve comprises many coal seams of varying quality and thickness. Erosion of the terrain has created coal out-crop lines that are encountered frequently with associated deviations in quality. Due to the complex nature of the coal reserve and the various customer quality requirements, coal quality control is a primary consideration and a constant challenge at the McKinley Mine. This paper will discuss the practices employed to ensure that the available coal meets contract specifications.

Jan 1, 1994

By J. M. Pachter

Property sales and acquisition are prominent features of today's coal industry. Before selling or buying a site, a company must know the property's economic net worth. Any evaluation of economic net worth would be inadequate if determinations of a property's environmental liabilities and costs were omitted. Short-term and long-term costs can result from liabilities related to reclamation, water treatment, subsidence, and hazardous waste disposal. A structured, interdisciplinary approach can aid in the delineation, summation, and scheduling of these costs and liabilities.

Jan 1, 1986

By Mark C. Holton

The mining industry has recently been. - experiencing a difficult period. Escalating costs, lower grades and deeper level mining, are a few of .the reasons' why interactive graphics or CADD (computer aided design and draughting) systems are increasingly being used. CADD systems which support powerful and flexible mining applications have great potential for making all forms of mining more efficient and effective. There are many application programs which address almost every aspect of mining. Most of these programs originated to satisfy a particular need. Graphics and other features were added until they, reached a point where they were commercially viable as a mining package. Because of their evolution these packages, lack many CADD-type features. Today there are powerful personal computers (PC's) and engineering workstations running the best CADD systems available. These systems, support hundreds of applications in almost every discipline. Mining was until recently not well supported by interactive graphics vendors because of the highly variable nature of mining and the lack of common standards. Users of CADD systems have experienced the benefits of CADD and come to expect similar features from graphic mining packages. Several developers of mining packagers have either attempted to include some CADD features or make their packages compatible with one or other CADD system. Mining can benefit greatly From a combination of interactive graphics (or CADD) and the right mining application software.

Jan 1, 1989

By James C. Barker

Alaska?s known mineral endowment includes some of the largest and highest grade deposits of various metals, including gold, copper and zinc. Recently, Alaska has also been active in the worldwide search for sources of rare earth elements (REE) to replace exports now being limitedby China. Driven by limited supply of the rare earths, combined with their increasing use in new ?green? energy, lighting, transportation, and many other technological applications, the rare earth metals neodymium, europium and, in particular, the heavy rare earth elements terbium, dysprosium and yttrium are forecast to soon be in critical short supply (U.S. Department of Energy, 2010). The REE, accompanied by other high field strength metals (such as Nb, Zr, Ti, Th, W), are associated with alkaline complexes of the Hogatza Belt in northwest Alaska; peraluminous tin-granites of the Ruby batholith in central Alaska and the Porcupine plateau in the northeast; and peralkaline intrusive complexes in the southwest Alaska Range west of Anchorage, and on Prince of Wales Island in southeastern Alaska. Limited evidence suggests that the heavy REE are associated with deposits that became more highly evolved by late hydrothermal processes.

Jan 1, 2012

By Keshavan Nair

In connection with Project Payette, which is concerned with the detection of underground nuclear explosions, it was necessary to determine the technical feasibility of constructing and maintaining a large (approximately 315 feet in diameter) unsupported underground cavity at a depth of approximately 2700 feet in the Tatum Salt Dome in Mississippi. The dimensions and the location of the cavity in the salt dome were governed by criteria laid down by the Atomic Energy Commission. Within the framework of the specified criteria, cavities of various shapes and dimensions could be utilized. One aspect of the feasibility study was to investigate the structural stability of various cavity shapes and to recommend a preferred shape. This paper summarizes the studies that were conducted to evaluate the structural stability of various proposed cavities.(l)

Jan 1, 1968

By J. R. Walls

The United States potash industry had its beginning in the early Colonial days. Potash was initially manufactured by leaching of hardwood ashes in large iron pots. Production of potash was recorded as early as 1631 in New Hampshire, and in Maine a few years later. According to the census of 1850, the production of potash was America's most thriving chemical industry and, at that time, 569 plants were reported producing potash from wood ashes. Interest in potash was so great prior to the 1800's that the very first United States patent, signed by George Washing- ton, was granted for the production of potash on July 31, 1790. A new era for the production of potash began when potash was discovered by the analysis from a brine well in 1839 near Stassfurt, Germany while exploring for salt. The predominant use of potash at that time was in the chemical industry rather than agriculture. The discovery, by Justice von Liebig in about 1858, that potash salt contributed greatly to the essential plant food in soil opened up an enormous potential market for a suitable potash material.

Jan 1, 1985

By J. R. Tonry

In the grinding of dry non-metallic materials such as rocks, ores, gypsum, lime, and cement clinker, it is recognized that only a relatively small portion of the energy is utilized for actual size reduction, and the major portion of the energy used is converted into heat. As a result, heat is generated inside grinding mills imparting to the ground product a higher temperature than that of the mill feed. In some cases, as for instance in grinding cement clinker and gypsum into finished cement, it may be desirable to keep this temperature increase within certain limits, to avoid any change in the properties of the product and, because consumers may specify a maximum temperature of the finished product for reasons associated, with the tulimate use of the cement. The actual proportions of heat and useful work are somewhat indefinite. Some tests have indicated that nearly all the energy is converted into heat, and. other investigators have found that they could account for "everything except the noise." Investigations sponsored by the American Institute of Mining and Metallurgical Engineers, and carried out with an adiabatic calorimeter, indicated that a surprisingly high 19 percent of the energy might actually be used for size reduc¬tion. However, for the purpose of the following discussion it will be assumed that: (Fig. 1) 10% is lost in motor and gears 10% is lost by radiation and convection from the mill body 10% is used for size reduction, and. that 70% of the energy input leaves the mill as heat in the ground. product. A typical example (Fig. 2) would be a 7x22-ft tube mill operating in open circuit, driven by a 400 hp motor, charged with 77,000 lb of grinding media and producing 70 bbl or 26,300 lb of cement per hour. Reducing this cement from a clinker size of 96 percent passing a No. 16 mesh sieve to a specific surface of 3,230 sq cm per gm (Blaine) will increase the temperature of the cement approximately 143F above the temperature of the feed, as explained later. If the tempera¬ture of the clinker therefore is 125F, the finished cement will be 268F, which in some cases may be too hot. : When cement temperatures approach a range during grinding where dehydration of the gypsum becomes a problem, a logical consideration would be some means of reducing the temperature before it attains the range conducive to gypsum dehydration. Regardless of the varying degrees of heat generated within the mill or mills during grindingto various finenesses, consideration of the maximum safe limit for any type of cement being ground, which may vary fromplant to plant, govern in refining the mill circuit to obtain a safe temperature range. All plants are not necessarily required to do the same cooling job, and may or may not use cement coolers following the grinding circuit. (Not discussed in this paper). In the past, various means have been employed for controlling this temperature increase, Such means have included water cooling of the outside of the mill shell; equipping the shell with cooling fins; injection of moisture inside the mill; ventilation through the mill; and., in cases of closed-circuit grinding, drawing cooling air through the classifier; the purpose in all such cases being to remove heat from the grinding system.

Jan 1, 1958

By M. Sears, K. Mohamed, J. Addis, J. Wickline, G. Rashed

To better understand the load shedding and the stress transfer on coal pillars due to room-and- pillar retreat mining in deep cover panels, researchers from the National Institute for Occupational Safety and Health (NIOSH) conducted a monitoring field study. Two sites, at overburden depths of 1,000 ft (304.8 m) and 1,500 ft (457.3 m), were selected in a room-and-pillar mine operating in Southern West Virginia. The deformation and stress changes in the roof and two adjacent pillars at each site were monitored during the retreat mining process. The monitoring results and field observations were used to calibrate large-scale FLAC3D models for each site. The calibrated models were used to assess different sizes of roof bolts installed in deep cover areas. INTRODUCTION Deep cover room-and-pillar retreat mining is an important emerging issue that will intensify in the future as shallower reserves are depleted (Mark, 2009; Chase et al., 2002). During pillar retreat mining, the likelihood of local and/or global instabilities increases due to elevated stress levels near the pillar line because of the abutment loading. In the last decade, approximately 31% of the room-and-pillar mining groundfall fatalities in the United States occurred during pillar retreat mining. Between 2013 and 2017, this proportion increased to 55%, of which 50% of these fatalities were due to falls of roof and rib that occurred during pillar recovery (MSHA, 2018). One interesting piece of information about pillar recovery fatalities was that the victim was nearly always under bolted roof. Sheared and broken #5 (5/8-in), fully grouted rebar bolt failure contributed to three of four fatal roof fall incidents that have occurred in deep cover retreat mines (NIOSH, 2010). This claim raised the following question at the study mine: Is it safe to use a 4-ft long #5 (5/8-in) rebar bolt grade 60 at a depth of cover more than 1,000 ft (304.8 m)? There was some concern about shear failure of the #5 (5/8-in) rebar bolt at a depth of cover over 1,000 ft (304.8 m). To answer the question and to reduce accidents and fatalities caused by ground falls due to room-and-pillar retreat mining in deep cover panels, the National Institute for Occupational Safety and Health (NIOSH) monitored the roof and rib deformation and the change in vertical pressure within two adjacent pillars during pillar recovery. The study was conducted at two deep cover sites in a room-and-pillar mine located in Southern West Virginia that operates in the Lower War Eagle (LWE) seam. The monitored sites were selected at 1,000 ft (304.8 m) and 1,500 ft (457.3 m) depths of cover. In this paper, site-1 represents the monitored site at 1,000 ft (304.8 m) of cover, while site-2 represents the monitored site at 1,500 ft (457.3 m) of cover. For this study, large-scale FLAC3D numerical models were calibrated based on both field observations and instrumentation results. The calibrated models were then used to compare the ground response and the induced stresses of two pillars at instrumented sites 1 and 2. The maximum lateral displacement (roof shift) obtained from the calibrated large-scale FLAC3D models was applied to a small-scale FLAC3D bolted models, the safety factor for axial stresses of the simulated roof bolts was calculated at the deep cover sites.

Jan 1, 2019

By H. Kimura

A new technology for ironmaking based on direct gaseous reduction of iron ore concentrate is under development. The process is based on the flash reduction of the concentrate particles in a gaseous reducing agent, such as hydrogen, natural gas, a reducing gas generated by partial combustion of coal, or a combination thereof. This technology is expected to drastically lower CO2 emission and reduce energy consumption by about 38% of the blast furnace requirements. The energy savings are possible largely due to the elimination of pelletization and cokemaking. Process design and simulation using hydrogen as the reductant for iron ore concentrate have been performed. A process flow sheet composed of a flash reactor, heat recovery system, water removal system for purifying recycled hydrogen, and all connecting streams was evaluated using the METSIM software. Ironmaking using two reactors was also designed and simulated, which could reduce the total required amount of hydrogen although it would increase the complexity of the flow sheet and operation.

Jan 1, 2010

By L. S. Fountain

A national survey, 1978-1980, found 180,973 waste impoundments used by industrial mining, municipal and other interests. Possibly 27,000 contain hazardous materials. The potential hazard of leaks polluting water supplies is a growing concern. An electrical technique was developed to efficiently and speedily detect and locate leaks in geomembrane-lined liquid impoundments without emptying the contents. A potential applied between the liquid and earth causes electric current to flow through leaks in the insulating geomembrane material to ground. The cur- rent density around the leak is used to detect and locate the leak. Field tests show single and multiple leaks 2.54 cm in diameter or less can be detected and located to within less than 30 cm.

Jan 1, 1986

By V. R. Voller

The WTBAL computer program for evaluating material balances for minerals processing flowsheets was developed at the MRC and has been in general use for a number of years. This paper reports on two enhancements to the basic MTBAL routine. The original program accounted for errors in the process measurements and used estimates of measurement variability to calculate stream weights. Unfortunately, the estimate of measurement variability was fixed over all streams. In the enhanced version of MATBAL, named IMTBL, the program equations and their solution procedure have been modified to allow the estimated variability in a process measurement to vary from stream to stream. The .second enhancement involves making MTBAL interactive. As such, the user now prescribes his information in an easy-to-use fashion in a conversational mode via a terminal. Finally, an assessment of the feasibility of implementing IMTBL on microcomputer systems will also be reported.

Jan 1, 1982