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By William Gleason

The evolution of technology has made the world a more connected place. It continues to change the way we power our homes and vehicles and is leading to a future that seems to be limitless. Limitless as long as we can continue to supply the minerals necessary for technology to produce better iPhones, more efficient electric cars, better wind turbines and sophisticated national defense systems. These minerals, dubbed critical minerals, have surged in importance in every corner of the world and, on Aug. 3-4, they were topic of conversation at the Critical Minerals 2014 conference in Denver, CO. The conference, hosted by SME and the Australasian Institute of Mining and Metallurgy (AusIMM), looked at critical minerals from every angle, from where they are found to what the future might be. Among the minerals that have been called critical are rare earths, a collection of 17 minerals that have become increasingly important as technology continues to advance in everything from communications to energy to national defense. Leading off the conference, David Abraham, senior fellow at the Institute for Analysis of Global Security, explained that, like many people, he is relatively new to rare earths. Unlike most people, though, Abraham developed more than a passing interest in the minerals and has since travelled the world to understand the role of rare earths ? where they are found, how they are mined, how they get to market and, eventually, what applications they are used in. Following his travels, he said he returned concerned about the sector and how the industry will keep up with the demand that only seems to be growing in the modern world. And, Abraham noted, that it is not just the developed world that is driving demand. It stretches even to places like Indonesia, where the average annual income is about $3,000/year. Yet, the nation is one of the most active places in the world for social media with a population that is wired in with all kinds of electronics. The problem facing the sector is, and has been for a long time, and especially since 2010, supply of the minerals. At one time, China produced about 98 percent of the world?s supply and controlled the sector completely. In 2010, as the world began to demand more rare earths and develop other sources, China announced an export ban on rare earths. This changed the game completely, from the production lines all the way to the floor of the U.S. Congress.

By Gilbert Sauriol

The mining complex, which the Mines Gaspé division of Noranda Mines Limited has operated in Murdochville since 1954, includes open pit and underground mines, two mills, one leaching plant and a smelter. The under- ground mining uses predominantly a large scale room and pillar method, rooms 15 m wide, 30 m high and 300 m long being common. Ore production is effected by 4.5 m3 front-end loaders and 32-tonne trucks powered respectively by 225 and 325 kW diesels. Daily dust and gas readings show that air quality can be maintained at an acceptable level with much less ventilation than that normally specified. This paper emphasizes the point that air requirements should be based on Air Quality Standards, thus allowing an operation to benefit from favourable conditions or from improvements such as exhaust treatment, fuel alteration, etc.

Jan 1, 1983

By L. H. Pye

For large mining sites in the west, the traditional method for performing an ecological risk assessment (ERA) provides little useful information for risk managers faced with selecting and designing sound remedial options. Current U.S. Environmental Protection Agency (EPA) risk assessment guidance largely supports quantitative risk characterization of individual species as surrogates for population and ecosystem-level effects. Developing a work plan for investigating and remediating ecosystem-level changes potentially caused by large-scale historic mining/smelting contaminant release requires a decision process that incorporates a more holistic ecosystem management approach. Some of the most wasteful efforts associated with mine site ecological risk assessments arise when the risk analysis and data collection programs are not specifically linked up-front to the risk manager's decision needs. The following paper discusses the importance of employing a decision-based, ecosystem management framework when conducting ecological risk assessments at large mining sites. A case study of an ecological risk assessment currently being performed at a large New Mexico copper mine site is presented.

Jan 1, 1999

By E. J. Onuscheck

With passage of the Federal coal' Mine Health and Safety Act of 1969, many challenges have been directed to the industry's mining and safety engineers. The most critical challenge is that of ventilation. The language concerning ventilation in many sections of the Act could very well deprive or limit the mining engineer in planning the ventilation for new mines, since the Act requires federal approval of all ventilation plans. Dependent upon approval and of course application of the law, this could, due to economics, prohibit the opening of new mines in some cases. Petitions for modification of some mandatory standards relating to ventilation have already been filed under Section 301(c). It is quite possible that many of these standards may be modified.

Jan 1, 1970

By Dean E. Albon

In the late 1940's and early 50's in southern Illinois, the usual open pit blasting in the coal field consisted of one or two rows of churn drilled vertical holes being shot with instant electric blasting caps. The entire shot detonated at one rime. In southern Indiana and Ohio most mines were drilling horizontal holes and they too were primed with instant EB caps. During the ten years from 1355 through 1965 many changes occurred in drilling and blasting methods. The churn drill in southern Illinois and the horizontal drill in Indiana and Ohio were replaced by the rotary vertical drill. The ammonia dynamites and liquid oxygen explosives were replaced by ANFO. The elctric blasting cap in the hole was replaced by a detonating cord down line and detonating cord trunk lines made the connections between holes and rows of holes. Host open pit mining was in areas far enough from town that the noise and vibration from blasting was, if not ignored, at least tolerated. During the 1960's open pit mining expanded to account for nearly 50% of the coal produced. Mines came closer to town and towns expanded along the highways with suburban homes and mobile homes. The mines began receiving complaints about the noise and vibrations from blasting operations.

Jan 1, 1976

By Stephen R. Pogorski, Nicholas Busigin, Colin R. Phillips

The movement of radon away from its source in porous media is determined by two key parameters: the fraction of the total radon formed which enters the intergranular pore spaces, termed the emanation coefficient, and the transport processes which exist in these pores such as diffusion and convection. The first parameter, the emanation coefficient, is of primary importance since it is a measure of the actual amount of radon which is free to migrate within the media. The effects of particle size and radium concentration on the emanation coefficient were examined using a quartz-pebble conglomerate ore from the Elliot Lake mining district of Ontario. It was found that the smallest particle size examined (<74 µm) had the highest radium concentration and contributed the most to the radon emanation. A one-to-one correspondence between radium concentrations for the various particle size fractions and radon emanation was not observed. Samples were examined using scanning electron microscopy and very small particulates were observed to be present on the particle surfaces. When these very small particulates were removed from the host particle surfaces by rinsing, the radon emanation decreased by a factor of 17. This result indicates that most of the emanation comes from the very small particles. The effect of moisture on the emanation coefficient was examined qualitatively and a trend of increased radon release with moisture content was noted.

Jan 1, 1981

By Maurice Rey

The copper segregation process is designed to concentrate oxidized copper ores or mixed sulfide-oxide copper ores which are refractory to normal and cheaper mineral dressing or leaching processes. Such ores contain copper silicates or highly disseminated copper minerals in a gangue not entirely free from limestone or dolomite. Concentra¬tion by flotation is, under these circumstances, not possible and the acid-consuming constituents do not permit acid leaching. A high temperature treatment at 700-800°C, in the presence of a small amount of sodium chloride and of finely divided carbon, concentrates the copper into easily floated metal by a kind of reducing chloridizing roast. The sulfides, if present, are either oxidized in the heating stage and react like oxides or float with the metallic copper in the flotation step. The ores which have the aforementioned characteristics and which are high grade enough to pay for the treatment are scarce, so that the process has only a limited application. Theory of Copper Segregation Sodium chloride, reacting with water vapor and the acid gangue constituents, produces hydrogen chloride which reacts with the copper minerals. The copper is volatilized as cuprous chloride and immedi¬ately reduced on the coal particles by hydrogen emanating from the volatile matter of the coal and from the water-gas reaction. Hydrogen chloride is

Jan 1, 1985

By S. I. Nozhko, V. N. Guliy, A. A. Zolotarev, L. M. Luyshnia

The study of the apatite deposits of the Aldan Shield shows wide spread of the Precambrian apatite-carbonate ores and possibilities of using them for extraction of apatite. Dependency of flotation on ore minerals was studied according to the following scheme: preparation of the monomineralic samples of anhydrite, gypsum, chlorite, serpentine, phlogopite, apatite; mixing them in apatite ore of the average composition; followed by flotation. Another series of the experiments was conducted to ascertain a dependence of flotation activity of the different minerals on the different flotation reagents, which were used as collectors. It has been shown that apatite from silicate-carbonate ores is most extractable because it has the biggest size of grains and is the most free of inclusions. Beneficiation of the sulphate-containing apatite-carbonate rocks is possible when flotol - 7.9 is used as a collector. Meanwhile, the use of the tallaktam leads to an increase in the sulphate recovery. The estimation of individual technological features of the layered Mghydrosilicates and their influence on the process of beneficiation has been examined using samples of apatite-dolomite ore (P205-8%) with the addition of the phlogopite, serpentine and chlorite. The results show that there is little influence of the chlorite presence on the flotation while the serpentine presence leads to a decrease of the flotation, because of its high specific surface area.

Jan 1, 1993

By Patrick M. Hurley

The spreading-ridge, or accreting plate margin, is the primary conduit of metals delivered to the earth&apos;s surface. Isotope ratios of lead show primitive mantle values at these sites, indicating that this is true. We can use lead isotopes in any mineral deposit to indicate the degree to which the metal is "primitive" in the sense of having been uncontaminated with U-enriched crust or "crustal" in the sense that it has been cycling at the earth&apos;s surface since earlier times. The reason for this is that the upper continental crust has an enrichment in the ratio of U/Pb over that in the mantle, so that old continental leads have a larger radiogenic component. The primitive metals delivered to the surface at the spreading-ridge are transported on the oceanic plate until they reach a subduction zone. Here they become cycled in the "orogen". However, in this process the primitive metals are mixed with metals from the continent so that the average lead isotope ratios are between those in the mantle and the average upper continental crust. Subsequently a part of the metals in the orogen may become fixed in a new block of continent. However there are processes which continue to uplift and erode ancient continental regions so that there is a continuous feeding back of metals to the orogen. We have therefore a cycling of metals from the existing continental crust into the orogen where they are mixed with new contributions from the spreading ridge and mantle.

Jan 1, 1977

By Meghan Murphy, Yiming Sun, Kush Chohan

DTX is a 1.3-mile-long rail extension being constructed by Transbay Joint Powers Authority to extend Caltrain rail service and future California High Speed Rail service to downtown San Francisco. It includes a 3,352-foot-long mined tunnel with a cross section varying from 50 to 60 feet wide and 43 feet high to accommodate two- and three-rail tracks. DTX will be excavated in mixed-face and Franciscan Formation with ground cover ranging from 40 to 85 feet. This paper discusses how mined tunnel design has evolved since the initial preliminary design phase over 10 years ago. The current design concept for tunnel construction is also discussed.

Jun 13, 2023

By J. Richard Tonry

In portland cement manufacturing, the raw materials axe changed to clinker in the burning operation. Generally the rotary kiln is used for this purpose and involves many processes, including pelletizing and nodelizing. This transformation is called clinkering, and is analyzed as now generally practiced in cement making, from the raw material to the resulting clinker.

Jan 1, 1963

By W. A. Hoyer

Neutron activation analysis for mineral identification has attracted the attention of numerous investigators, judging from the publications on this subject in the past few years. 1-9 The appealing aspect of this method of mineral analysis is its proven sensitivity in the laboratory. In principle, activation analysis is one of the few petro-physical methods whereby a direct analysis for a mineral itself is possible in a borehole. The successful application of activation analysis requires the use of particular neutron reactions, measurement of selected gamma-ray energy intervals, and optimum bombardment and detection times. For copper analysis, Labanov et al., 10,11 using a low-energy PuBe source, reported an acceptable logging means. On the other hand, Pradzynski12, in analyzing ores and process tailings, used high-energy neutrons and photons for surface measurements of process samples. The work of Labanov et al. was based on measuring the rate of decay of the activated copper and hence was not as definitive as might be desired. Equipment is commercially available to carry out activation studies in the field 13,14 Gamma-ray spectra can be successfully transmitted over ordinary logging cables and, with borehole high-energy neutron accelerators and lower-energy chemical neutron sources, a variety of neutron activation methods can be studied. The purpose of the study discussed in this paper was to determine the feasibility and practicability of logging for copper using neutron activation techniques and commercially available equipment. The laboratory study showed that Cu could be detected in rock samples in the laboratory by high-energy neutron activation of 63 Cu. In the field, however, due in part to the large volume irradiated, the direct detection of copper using high-energy neutrons was not as promising. Detection of copper by measuring both the direct gamma-ray emission and the excessively strong low-energy gamma-ray absorption appears promising. Copper was not detected either in the laboratory or

Jan 1, 1972

By C. K. Skokan

Various geophysical tools have been tested over the last eight years to evaluate their usefulness in defining damaged rock zones in an underground facility at the WIPP site in New Mexico. These tools include direct current and frequency domain electrical methods and seismic tomography. The electrical measurements show a "drying rind" to exist around older excavations. Seismic tomography confirms that a rind of lower velocity has developed along walls. In combining these tools, a monitoring program has been proposed to observe long-term changes in bedded salt. Results from the monitoring of electrical data over a 2-year time period illustrate the applicability of the technique in an underground environment.

Jan 1, 1993

By William R. Bond

The pressure/vacuum lysimeter is being used as an effective vadose zone monitoring device for mining heap leach facilities, tailing disposal ponds and tailing waste sites. Their use has proven reliable for baseline data collection, early warning leakage detection and analyzing geochemical variations in the vadose zone. The lysimeter structure utilizes a closed cylindrical chamber made of PVC or inert material. The soil water intake portion of the cylinder is made of a porous material of low permeability. The application of vacuum or pressure to the unit is via two access tubes from the ground surface. Available soil moisture is drawn by vacuum through porous material into the lysimeter chamber and then collected from the access tubes. Case studies show their usefulness for monitoring around a uranium tailing pond constructed in glacial till material, under heap leach pads and pregnant, barren, and overflow ponds, and investigating the movement of contaminant moisture through old tailing deposits. Relatively easy to install and sample, regulatory agencies and facility operators are accepting and negotiating for their application as a site integrity monitoring device and unsaturated zone research tool. Their use at heap leach facilities lends credibility to solution balance calculations when considering a leachate loss of 5 or 10 percent can make or break a mine&apos;s profitability.

Jan 1, 1984

By C. J. Weiss

"A commercially available Through-the-Earth (TTE) communications system was evaluated at an underground coal mine in eastern Kentucky. This field study was conducted as part of a larger multi-site evaluation of available TTE systems to determine their operational sensitivity. Field testing is being performed along with simulation techniques developed for geophysical surveys. The results of the field test will additionally be used to determine the applicability of these simulation techniques to TTE communications. The mine detailed in this paper was idled at the time of the study, which provided the nearest practical representation of a post-event mine shutdown. For this study, the three following communication modes were tested: surface-to-underground, underground-to-surface and surface-to-surface. Standard deployments of the TTE system using the manufacturer’s recommended procedures were able to achieve clear communications between underground and surface locations. Other arrangements of the units yielded intriguing results, some of which were predicted by computer simulations, others were unexpected. Future experimentation is planned to further evaluate the observed phenomena. INTRODUCTION The ability to establish effective communication between surface and underground personnel after a mine event is essential for both mine evacuation and mine rescue efforts. Current communication technology is reliant on physical infrastructure, such as antennas, cables, and repeaters, located throughout the mine. Such systems are easily disabled during a mine event because of their vulnerability to physical damage. A true emergency communications system would have the ability to function regardless of a mine’s physical state. Through-the-Earth (TTE) wireless communications technology has the potential to provide such a tool. Wireless TTE communications are exceptionally challenging because electromagnetic (EM), or radio, signals are subject to drastic attenuation as they travel through solid strata. In addition to attenuation, EM wave propagation is directly affected by the physical and petrographic characteristics, mineral compositions, metamorphic properties, and the degree of water infiltrations in the strata [1-5]. These strata characteristics are unique to each mine thus making the design of an effective, universally deployable, and reliable TTE communications system very difficult. At present, TTE technology is in the preliminary stages of practical deployment with only a few permissible TTE systems commercially available."

Jan 1, 2015

By R. Kingman

At Tahawus, New York, National Lead Company operates the MacIntyre Development, This operation produces 10,600 long tons of ore per day for crushing, 8,000 tons for grinding and processing, of which 2,000 tons per day reports as tailing for disposal in an impounded tailing storage area. With the change in location of mining operations at the mine of National Lead Company, a change in the area for tailing disposal by gravity became necessary, This called for the diversion of tailing from near the proposed mining area to areas more favorable for long term storage by gravity. In order to avail the operation of maximum storage for the future, a uniform minimum grade launder was proposed with a minimum velocity and maximum outfall at the discharge. Disposal of the gravity and flotation tailing was formerly accomplished in open ditch from the concentrator at a grade of 1.5 percent. It was desirable to design the new launder at grades less than this for the greater storage elevation.

Jan 1, 1966

It doesn&apos;t take any special acumen to note that US engineering and construction firms are busier than ever with mining projects in this mineral conscious world. This special issue of Mining Engineering takes a look at E&C companies-their expanding role, their special capabilities, and their challenges and problems. ME sent a questionnaire to a representative sample of E&C firms. Information was sought about officers, ownership, and amount of business. ME also asked about types of projects and commodities dealt in as well as market distribution and forms of payment. The accomnanying charts show how the 17 responding E&C firms answered these and other questions. Other ME survey questions, and a review of company literature, yielded information about financing techniques and special challenges for E&C firms. Insights were gained concerning government impacts, customer-generated problems, and promising areas for development-including synfuels-in the minerals industry. These areas are discussed later in this article. Accompanying articles in the special issue discuss the E&C company&apos;s role in mining projects, research and development in E&C firms, one approach to contract work used by an E&C firm, and an E&C project case study.

Jan 10, 1980

By R. E. Wagner

Consistent increase has been the mark of North American potassium (K) consumption. In 23 of the last 25 years there was upward progress The pace of usage has quickened in the past three or four years This, together with a predicted accelerated future demand, has created unprecedented interest -and activity in the potash industry. Potassium enjoyed a ninefold increase in consumption from 1940 to the present time in North America (Figure 1). Since 1950, it increased from just over a million tons of potash (K20) annually to nearly three million tons in 1964. World-wide usage exclusive of mainland China is now about 10 million metric tons. Some predictions call for another doubling in consumption in the next 10 to 15 years, About 20 percent of the four million tons of K20 produced in North America is now exported overseas and this percentage is likely to increase in the years ahead. Ten years ago, exports represented only 3-1/2 percent of total K2O production from this continent.

Jan 1, 1966

By Martin J. Hughes

The Eagle Mountain Mine of the Kaiser Steel Corporation is located in the California portion of the Colorado Desert at a distance of about 60 miles east of Indio, California. At the present time, this mine is producing at the rate of 5,000,000 tons of concentrate per year. A total of 1,000,000 tons of ore per year is presently being sold on the Japanese market while the remainder is consumed by the Kaiser Steel Company blast furnaces at Fontana, California. A new Pellet Plant and Concentrator is presently under, construction with completion scheduled for May or June 1965. This plant will have a rated capacity of 2,200,000 tons of pellets per year and essentially all of this production will be sold to Japanese steel companies.

Jan 1, 1965

By Stefan Medel

As a pioneer Herrenknecht started in 2018 to automate the production of tunnel lining segments. Since then, many automation processes became state of the art. Robots cleaning and oiling the moulds, hydraulic units opening and closing them fully independently. Artificial Intelligence (AI) controls the works and ensures the quality requirements. Data management has become a massive tool from a simple data collector towards a control and optimization tool. Sensors controlling concrete maturity and supporting the precast team to optimize the concrete mix. These state of the art and new innovations will be presented in this paper.

Jun 23, 2024