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By E. T. Tuzcu

Microscale information about single particle fracture can be incorporated into the macroscale model of the whole size reduction process in the mill. The ultrafast load cell (UFLC) device provides a substantial amount of information about fracture characteristics of a particle under impact loading. UFLC captures high-resolution compressive force signals during particle breakage. The measurement of the compressive force at the instant of fracture of the particle allows computation of a number of comminution-related particle properties, as well as the energy absorbed during fracture. In the current study, limestone particles 50 mm in size were fractured to obtain specific fracture energies. Then, based on the experimental data, two models were proposed to quantify the fracture process. The specific fracture energy distribution of the particles in the range of 6 to 50 mm was defined by the well-known Weibull distribution. The other model is a probabilistic fracture model. This model is a link between energy events occurring in a grinding mill and the breakage rates of particles. The impact energy spectra or energy events occurring in a grinding mill can be obtained with a discrete element method (DEM) simulation. One can model the breakage rates of the mill material by combining the energy spectra with the probabilistic fracture model. This novel approach for the modeling of breakage rates via DEM and UFLC is shown here.

Jan 1, 2011

By E. T. Tuzcu

Microscale information about single particle fracture can be incorporated into the macroscale model of the whole size reduction process in the mill. The ultrafast load cell (UFLC) device provides a substantial amount of information about fracture characteristics of a particle under impact loading. UFLC captures high-resolution compressive force signals during particle breakage. The measurement of the compressive force at the instant of fracture of the particle allows computation of a number of comminution-related particle properties, as well as the energy absorbed during fracture. In the current study, limestone particles 50 mm in size were fractured to obtain specific fracture energies. Then, based on the experimental data, two models were proposed to quantify the fracture process. The specific fracture energy distribution of the particles in the range of 6 to 50 mm was defined by the well-known Weibull distribution. The other model is a probabilistic fracture model. This model is a link between energy events occurring in a grinding mill and the breakage rates of particles. The impact energy spectra or energy events occurring in a grinding mill can be obtained with a discrete element method (DEM) simulation. One can model the breakage rates of the mill material by combining the energy spectra with the probabilistic fracture model. This novel approach for the modeling of breakage rates via DEM and UFLC is shown here.

Nov 1, 2011

By Dapeng Zhang, Brij Moudgil, Shibo Zheng, Chunhui Feng, Wenyi Song, Wending Xiao, Patrick Zhang

The separation of dolomite from phosphate is the most challenging problem in phosphate mineral processing. More than 50 percent of the phosphate reserve in Florida contains too much dolomite to process using current industry practice. The current way of producing phosphoric acid requires less than one percent MgO in the phosphate concentrate as the feed material. The Florida Industrial and Phosphate Research (FIPR) Institute has collaborated with worldwide experts in the field to address this issue. As a result, the industry is now offered three feasible options. Option I entails three methods for reducing MgO content in the concentrate from the Crago process, including adding a dolomite depressant in the rougher flotation step, dolomite flotation of the cleaner concentrate, and scrubbing the cleaner concentrate in quartz sand, which could reduce MgO content in the final concentrate by 20 to 40 percent. Option II involves the crushing and grinding of high-dolomite phosphate pebbles followed by dolomite flotation at slightly acidic pH using a new collector that does not require phosphoric acid as a phosphate depressant, achieving a final concentrate analyzing less than 0.9 percent MgO at about 87 percent P2O5 recovery. Option III is a gravity separation technique using an innovative separation jig, and its full potential remains to be demonstrated.

By Lawrence R. Molsather

Certain hydrologic parameters are affected by development of a mine. These include the area, yield, and storage in a watershed. Alteration of these parameters results in variations in lake levels and stream flow rates and in changes in ground water elevations and gradients. These factors have become increasingly important in light of present environmental design standards and government regulations. Mitigation of adverse hydrologic impacts can be costly and can create operating constraints which complicate the mining process.

Jan 1, 1980

By James B. Fletcher

The Miami mine is located near the town of Miami, Gila County, Arizona. The Miami mine started mining in 1910 and finished in July, 1959. The orebody was divided and mined as follows: Tons High Grade 24,400,000 - Top slicing, sub-level caving, etc. Low Grade 105,100,000 - Block caving Mixed ore 9,800,000 - " Low Grade #2 13,100,000 - " Total Mining 152,400,000 GEOLOGY Ore minerals are largely in pre-Cambrian Pinal schist intruded by tertiary Schultz granite porphyry and covered to some extent by Quarternary Gila conglomerate. The structures are highly faulted and shattered. The Miami fault on the east cuts off the ore and the Pinto fault on the southwest caused re-oxidation of enriched sulphides producing mixed ore. MINERALOGY The chief mineral is chalcocite, with chalcopyrite, bornite, covellite, malachite, azurite, chrysocola, cuprite, native copper, and molybdenite as minor minerals. The ore minerals occur in seams, veinlets and disseminated particles. In block caving there is always some dilution, and drawing of ore stops when the grade drops past an economical point. This results in a small amount of copper left in the stopes below the capping. There is some copper in the capping, probably below 0.03% or less than 0.6 lbs. per ton. Over the low grade #2 orebody and portions of the high grade there was an oxide capping which was not mined. The crushed pilars are another source of copper. The leaching at Miami is an attempt to recover this last remaining copper of a worked-out mine. The enrichment at the Miami mine had gone more nearly to completion than most ore bodies in the southwest. There is practically no pyrite in the capping and very little in the ore.

Jan 1, 1971

By Keith K. Griffiths

Computers are a valuable tool to the aggregate industry and should not be overlooked. The selection of proper mechanical components is necessary. Merely the addition of a computer to operate a mechanical system will not guarantee that the system will work. Material delivery by rail or truck for stock-piling and intra-plant material transfer can be accurately supervised by automation with simplified controls for the layman to use. There are mechanical problems that occur in material blending and load-out systems when such a system is automated. Such things as material flow, bridging, stockpiling methods, overloading of equipment and safety must be considered. How these problems can be overcome by proper selection of compatible mechanical and computer equipment will be discussed. Also, there are many individual material circuits in a plant that can be computerized at a nominal cost. This type of computer installation will not necessarily result in increased production, but it will produce greater efficiency in manpower. These small computers, binary counters, memory circuits and other devices and their application to the aggregate industry will also be presented. A careful evaluation of the mechanical and computer inter-relationship by someone understanding both "Rocks and Electronics" is essential to proper handling of material by computers. Computers for the mining industry may be either digital or analog computers. Unless the computer is to control some type of chemical process, such as a cement plant, the, analog computer is not required and the digital computer' will be quite adequate and less expensive.

Jan 1, 1967

By Sebastian Avalos, Julian M. Ortiz, Willy Kracht

Semi-autogenous grinding mills play a critical role in the processing stage of many mining operations. They are also one of the most intensive energy consumers of the entire process. Current forecasting techniques of energy consumption base their inferences on feeding ore mineralogical features, SAG dimensions, and operational variables. Experts recognize their capabilities to provide adequate guidelines but also their lack of accuracy when real-time forecasting is desired. As an alternative, we propose the use of real-time operational variables (feed tonnage, bearing pressure, and spindle speed) to forecast the upcoming energy consumption via machine learning and deep learning techniques. Several predictive methods were studied: polynomial regression, k-nearest neighbor, support vector machine, multilayer perceptron, long short-term memory, and gated recurrent units. A step-by-step workflow on how to deal with real datasets, and how to find optimum models and final model selection is presented. In particular, recurrent neural networks achieved the best forecasting metrics in the energy consumption prediction task. The workflow has the potential of being extended to any other temporal and multivariate mineral processing datasets.

Jun 16, 2020

By David M. Abbott

"The picture of the baby surrounded by the number of (usually) pounds of a variety of mineral products a newborn will use in a lifetime has been widely distributed over the years, both on the web and as business cards that could be distributed to anyone. Figure 1 shows a typical example. I have included a slide of the mineral baby in various lectures over the years, particularly in my lecture “Industrial minerals: much used, little recognized.” The mineral baby with associated estimated lifetime mineral quantities is updated every year. I collected a set of past mineral baby pictures to examine the changes in the quantities of the various mineral products over the years.The mineral baby was introduced by the Minerals Information Institute (MII) in 1999 and became known as the “MII Baby.” SME took over MII in 2008 and continued publication as the “MII Baby” until the merger of MII with SME’s GEM program in 2011 to form SME’s Minerals Education Coalition (MEC). MEC is now the publisher. Figure 2 is the 2016 version of the mineral baby. The repositioning of the picture of the baby from lying on its back to crawling reflects a major design change to help emphasize that SME’s MEC is now the mineral baby’s publisher.Data sourcesThe data used to prepare each year’s mineral baby comes from the National Mining Association, which collects the preliminary annual mineral commodity data from the U.S. Geological Survey (USGS) and other sources. This preliminary data becomes available late in the first half of each year. The life expectancy data for each year comes from the Center for Disease Control’s “Data and Statistics by Topic” and the population data comes from the U.S. Census Bureau’s “Quick Facts” tab.The source mineral data is compiled using metric tonnes as the basic unit. The quantity of of each mineral is the apparent U.S. consumption each year."

Jan 6, 2017

By Ray H. Hario

Background of Erie Mining Company Erie Mining Company, managed by Pickands Mather & Co., is one of the largest producers of iron ore pellets in the United States. The plant is located at Hoyt Lakes, Minnesota, sixty-five miles north of Duluth on the eastern end of the Mesabi Range. Taconite Harbor, situated on the north shore of Lake Superior, is the location of its Power Plant and shipping facilities. (Figure 1) Even though the plant commenced operation in September, 1957, its true be-ginning can be traced back to 1931 when Pickands Mather, in conjunction with Bethlehem Steel Corporation and Youngstown Sheet and Tube Company, began investi-gating the possibilities of processing low grade ores. In 1940, Erie Mining , Company was formed. During the early and middle 1940's, laboratory and pilot plant research was proven to a point where a preliminary plant was deemed feasible and built in 1948. This plant had an annual capacity of 203,200 t (200,000 long tons) per year and, until mid-1952, was the only taconite plant in existence using commercial-size equipment. During this period, ownership of Erie Mining Company was expanded to include Interlake, Inc. and The Steel Company of Canada, Limited. In 1953, authorization was obtained from the owners to build a 7.62 M t (7.5 M long tons) per year plant at a cost in excess of $300,000,000.

Jan 1, 1977

The viability of physico-chemical purification methods such as selective flocculation for separation of two components having similar chemical composition and same crystal structure but different surface properties is demonstrated. Loss of selectivity was observed in a dolomite-dolomite mixture with Polyethylene Oxide (5 million molecular weight) as the flocculant. Hetero-flocculation was minimized using a low molecular weight PEO (MW -105) as the site blocking agent (SBA). Near complete separation was achieved at pH 10.5 at 100% recovery level.

Jan 1, 1993

By M. S. Celik

Beneficiation of boron minerals by flotation with well defined systems has been very little investigated in the literature. The difficulty arises from the fact that boron minerals cover a spectrum of solubilities. Colemanite, a calcium containing relatively insoluble boron mineral, and borax, a highly soluble boron mineral have been used to exemplify the flotation of boron minerals. The floatability of both minerals using sodium dodecylsulfonate and dodecylamine hydrochloride exhibits considerable differences in their response to flotation. This has been ascribed to variations in the solubilities 0f boron minerals and the presence of the cations in the lattice structure. Flotation tests along with zeta potential measurements are used to elucidate the mechanisms involved in the flotation of boron minerals.

Jan 1, 1992

By Clifford W. Schultz

Four native copper ores, two conglomerate and two amygdaloidal, were tested to determine their amenability to sorting. One of them, a conglomerate ore from the Kingston mine, showed a high sortability as evidenced by an 80 pct recovery of copper in the minus 6-, plus 1/2-inch size range. Using the Kingston as a case example, the cost of mining and concentrating was estimated for a standard case and five optional cases involving varying degrees of sorting. This analysis indi¬cates that the production cost per pound of copper can be reduced on the order of 1 to 1-1/2 cents per pound along with a significant decrease in capital investment.

Jan 1, 1975

By K. Fleck

Energy West Mining Co. (EWMC) has implemented a geologic program for improving stability and support requirements along deep two-entry longwall gateroads at its Deer Creek Mine operations located near Huntington, UT. Together with geotechnical monitoring and concurrent review of mine seismicity in cooperation with MTI staff, it has become possible to improve longwall layout designs for two seam extraction of the Hiawatha and Blind Canyon seams. The geologic program consists of surface and in-mine exploration drilling, surface and in-mine geologic mapping, rock mechanics testing and detailed measurements of changes in depositional and structural conditions during development of every longwall gateroad. The geotechnical program consists of underground measurements at seven locations in two neighboring mining districts located in the Hiawatha and Blind Canyon coal seams under moderate to deep cover. Within the last five years, additional measurements, including data on seismicity and face conditions, have been incorporated into the data collection program for verifying the in situ coal strength and load transfer mechanisms for improving two-seam designs and support systems.

Jan 1, 2012

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

"Surface subsidence caused by underground room-and-pillar mining operations and by solution mining operations have been studied separately but never in combination. 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. Using Salt_Subsid, a subsidence software package from the Solution Mining Research Institute, and ArcGIS, Esri's mapping platform, 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 backgroundFMC Minerals has increased the production of trona from its Westvaco Mine near Green River, WY, 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 488 m (1,600 ft). 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 is removed and the size of the cavern created by the solution mining operations are 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 between surface subsidence measurements and 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 relationships between the measured subsidence and the solution mining activities. The project attempted to develop an equation that could be used to predict solution trona production based on measured subsidence. The project attempted to model the relationship between the measured surface subsidence and solution mining production using Salt_Subsid, an existing subsidence software package from the Solution Mining Research Institute (SMRI, Clarks Summit, PA) to estimate the location, size and shape of the solution mining cavern. This study would determine the program’s usefulness for locating and developing the cavern created by secondary solution mining activities. The subsidence and production data sets used in this study were collected over a seven-year period from 2008 through 2014."

Jan 4, 2018

By Weiguo Xie, MARK LAPUTKA

The pyrometallurgical industry plays a vital role in producing metals for our modern life. With growing demand for metals and declining grade of mineable ore, innovations become critical for many mining companies. This has given rise to the need for a review of recent improvements to the pyrometallurgical industry in terms of analytical measurement techniques, process and equipment improvements, and computer-based modeling/simulations. Because many of these innovations tend to be applied to a wider scope of metals, not restricted to a specific metal, we studied the broad applications of many improvements to a wide range of metals. We found that the challenge of a lack of robust measurement techniques under high-temperature conditions within a furnace hinders optimization of a pyrometallurgical process. Some future opportunities in the pyrometallurgical industry on analytical measurement techniques, computer modeling, and processes and equipment were also outlined and discussed.

By William R. Bush

This paper is a presentation of findings based upon an econometric model of the world zinc industry. The model was developed as a simple but useful aid for long-run forecasting and planning purposes. A structure was developed for both simulating real zinc price effects on production and consumption, and for forecasting long-run annual zinc prices and supply/ demand levels. Moreover, a methodology is provided to incorporate the effects of: (1) historic technological advances in zinc supply, and (2) the development of the competitive plastics industry. Finally, reduced form equations are used to generate ex post forecasts to evaluate the model's performance.

Jan 1, 1979

By S. K. Ghosh

This paper discusses how the information on ash composition, ash-fusion temperatures, and ash-slag viscosity can be utilized to predict slagging and fouling potentials of a particular coal. A review of several empirical parameters which are commonly in use for determining such potentials is given. Also, some guideline values for interpreting the relative propensity of slagging and fouling of various types of coal are provided.

Jan 1, 1983

By D. Bahrami, G. Danko, W. Asante

"It is prudent to interpret atmospheric monitoring signals in real-time for checking the safe limits of the air conditions in underground mines. In gassy mines, such real-time evaluation increases the safety of operation. In all mines, the continuous monitoring and evaluation contribute to maintaining air conditions to be within healthy and safe limits. Signal interpretation for safety conditions in mines is difficult for many reasons. An increase of hazardous contaminant concentrations can be predicted by signal pattern recognition, root-cause analysis of rapid changes toward deterioration and forward prediction in time using algorithms and numerical models. This paper focuses on analyzing signal patterns to recognize dangerous trends as well as forward predicting the various environmental and working conditions that may affect safety in underground mines. Efficient numerical ventilation model with heat and gas contaminant simulation components is needed for the analysis of real-time atmospheric monitoring data. Computational speed enhancement methods are discussed and tested in numerical examples, using the Jacobian sensitivity matrices for signal propagation prediction. INTRODUCTION The focus area of this paper is mine safety, related to hazardous atmospheric conditions in a mine ventilation system. Improvements by recognizing safety hazards caused by heat of combustible gases or the accumulation of poisonous gases in a mine are addressed. The recognition of safety hazard by manual evaluation is difficult because of the complex nature of information and the large amount of monitored data from measurement by atmospheric sensors such as air velocity, pressure, hazardous gas contaminants and temperature. In order to recognize problem-causing trends, it is necessary to evaluate continuously individual measurement data from the Atmospheric Monitoring System (AMS) of the mine during their time-dependent variations. In addition, the combined effects of various signal trends need to be simultaneously interpreted in their cross-effects. It is very difficult to foresee the possible outcomes of intertwined signatures of various problems by continuous human observation. For example, a steady, continuous methane concentration measurement together with a sharp drop in barometric pressure from the AMS sensors may be a case for worry in future time due to pressure-induced methane increase from the coal seam or the gob (Danko et al., 2013). This future increase can be predicted by a time-dependent Ventilation Air Model (VAM) and its surrogate Air Parameter Predictor Solver (APPS) model. A calibrated VAM or APPS model can indeed predict a likely methane concentration variation in future time as a function of previous and new air pressure as well as air velocity (Danko, et. al., 2013). Such a future trend, however, cannot be seen from the raw measurement data."

Jan 1, 2017

By E. B. Jensen

The results of an extensive one- year test period of a nonelectric explosives detonating system led to the mine-wide adoption of this system at the Henderson Mine in early 1978. Since that time, extensive experience with nonelectric initiation has verified the earlier results which include the following benefits: 1. Increased blasting safety 2. Improved productivity 3. Cost effectiveness 4. High reliability At the present time, while electric blasting caps still experience a limited use restricted to trunkline initiation, all heading rounds as well as the longhole bell, undercut, boundary cutoff and raise blasting are detonated non-electrically. The primary blasting agent used is AN/FO, and primers are typically one of the following products (depending on application): PETN, semi-gelatin dynamites or a nonnitroglycerin water-gel slurry.

Jan 1, 1982

By David A. Fawcett

An auxiliary cross-pit mining system, working in tandem with the prime excavator, is evaluated technically, operationally and economically for application in the selective removal and replacement of soils and unconsolidated ovezburden. Previous studies on cross-pit technology and applications of this technology are briefly reviewed. Stratigraphy plus pit, operating and economic parameters are assumed and applied in the evaluation and comparison of a base case dragline system with two alternatives - a dragline/scraper-dozer combination and a drag- line/cross-pit system combination. The economics of the proposed cross-pit system favour it as a viable alternative to conventional systems.

Jan 1, 1981