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By J. Alatalo

Autogenous grinding is a process of reducing the particle size distribution of an extracted ore by using the ore itself as the grinding media. It is a process that is difficult to control and there is a lack of knowledge of the events occurring inside the mill. To find out more about how the mill behaves under different processing conditions, a full factorial test was performed with iron ore in a pilot-scale pebble mill at the LKAB R&D facility in Malmberget. To complement this work, a strain gauge detector was embedded in one of the mill?s rubber lifters, the Metso Minerals continuous charge measurement (CCM) system, and was used to get more information about the charge dynamics. The data from the experiments has been analyzed. For production purposes, an increase in the number of particles smaller than 45 µm can be regarded as a probable increase in the production rate. The analysis shows that there will be an increase in fines at 65% of critical speed, especially when the mill is 45% full. This setting will also increase the power consumption, but improves the grindability of the ore even more. The deflection of the lifters is smaller for lower critical speeds. A higher degree of filling also gives a smaller toe angle and a higher shoulder angle as expected.

Nov 1, 2011

By A. E. Koski

This paper will review recent developments in the area of mine planning at the Empire Mine. It illustrates how one of the largest iron mines in North America has adapted computerized mine planning to meet the unique requirements of their mining operation.

Jan 1, 1994

By T. W. West

During the design and construction of a coal preparation facility, there are many items that can cause serious problems if not properly handled in the early stages of a project. These problems can be a detriment to smooth owner/ contractor relationships, the designing of a flow sheet, the selection of equipment, the design of the facility, the maintenance of schedule and budget, and a smooth start-up. It is the purpose of this presentation to identify some of these problems and to suggest steps that can be taken to reduce or eliminate their impact.

Jan 1, 1977

By X. Cai, L. Jiang, G. Fu

A process for recovering manganese from low-grade manganese oxide ore through a reduction acidolysis-selective leaching method is investigated. Two types of biomass, sawdust and straw, were used as reductants. Reduction acidolysis, using concentrated sulfuric acid, was used to disrupt the structure of the biomass, allowing the biomass to be hydrolyzed into monosaccharides. Analysis by X-ray diffraction revealed that Mn2O3 was reduced to MnSO4. Then, in the selective leaching process, iron was removed through the formation of goethite. The optimized experimental parameters are as follows: reductant to ore mass ratio of 0.4, sulfuric acid to ore mass ratio of 0.9, water to ore ratio of 0.5, aging time of 18 h, leaching temperature of 95 °C, leaching time of 90 min, and solution pH of 2.5 to 2.8. Under these conditions and using sawdust as the reductant, the manganese leaching efficiency and iron removal efficiency were 91.8 and 99.2 percent, respectively.

By R. S. Datta

Regulations on sulfur emissions have caused the electric utilities to evaluate various methods of meeting them. Low-sulfur, low-volatile coals can be burned alone or blended with high-volatile? coals. This option may be a cost-effective alternative to the installation of scrubbers on coal-fired combustion systems. In some blending applications, problems may be encountered because the low sulfur content and high calorific value of the low-volatile or other clean coal allow it to economically upgrade extremely poor quality coal. While this is done to meet specification purposes, actual boiler performance may be dominated by the poorer quality coal. Thus, the reputation of the low-volatile or other clean coal suffers. As a result of laboratory and full scale testing, conducted over the last five years, a model has been developed to evaluate the relative combustion characteristics of various coals and coal blends. A database for different coals has been gathered. This paper presents the model and shows how power plants and coal mine personnel can use it to evaluate their coals from different sources. It can be used to blend two or more coals from different sources so that thee blended coal has flame stability characteristics which are similar to those of the baseline coal.

Jan 1, 1991

CVRD was established on June 01, 1942, during the Second World War, through an agreement between Brazil, the United States and the United Kingdom, to produce 1.500.000 tons/year of iron ore from Itabira mines in the State of Minas Gerais. As a result of several circumstances and political problems (the end of the 2nd World War reduced the Anglo-American support to its development and implementation), the venture just reached the originally targeted production 10 years after its establishment, operating within a mine, railway and port integrated system. Currently, this operational system from the South of Brazil owns mines in the State of Minas Gerais with an annual capacity of approximately 65 million tons, 900 km of railways, of which more than 500 km is a double line railway, six pelletizing units and the Port of Tubarao for ships with large carrying capacity.

Jan 1, 1994

By Ali Keneti, Xavier Ryan, Gerardo Sanchez, Shannon Goff

In this study, FLAC3D modeling was conducted for ground-structure stability assessment for a pilot tunnel passing under a large shaft excavated in the vicinity of existing structures at Karangahape Station for the City Rail Link Project in Auckland, New Zealand. The analysis involved generation of the geometries and construction sequences in Rhinoceros®, modeling the existing ground condition, calibration of the simulated in situ conditions with the observed behavior of the ground, and excavation of the shaft and the pilot tunnel. A comprehensive interpretation of the results was then performed accompanied by comparison of the predicted behavior with the observed response of the ground during construction.

Dec 1, 2022

By B. Anamaeric

Economic, environmental and operational disadvantages of the traditional blast furnace process has led to the development of direct smelting reduction processes, including those that utilize self reducing/ fluxing dried greenballs as iron oxide feed materials. This is mainly due to improved carbothermic reduction, carburization and reaction kinetics. In this paper, the morphological changes of the greenballs as they transform to pig iron nuggets are examined over time at a constant temperature of 1,400° C. The products produced after each treatment were characterized using optical microscopy, scanning electron microscopy/energy dispersive spectroscopy and point counting/image analysis. The changes in the percent metallized area, wustite dendrite and slag matrix content of the structures were calculated. It was determined that the transformations were initially controlled by dissolving and containment of iron oxides in the molten slag and their consequent reduction to iron, followed by coalescence of the metallized areas. The final transformations were controlled by the carburization of the metallized areas.

By Ted H. Eyde

Nearly 17 years ago a major producer of synthetic zeolites started an extensive exploration program for natural zeolite deposits which resulted in the discovery of over 170 occurrences in the western United States. A few years later several of the other producers and consumers of synthetic zeolites also started similar exploration programs. Since then, small quantities of natural zeolite minerals have been produced from at least 12 deposits in the United States. Of these the Bowie deposit, about 13 miles north of Bowie, Arizona, is the most important,having produced over 5,000 tons of vitric tuff zeolitically altered to the mineral chabazite and minor amounts of the minerals erionite and clinoptilolite. Mining Districts and Mineral Deposits of Arizona compiled by Charles A. Mardirosian, Consulting Geologist, estimates the value of the total production from the Bowie deposit at a very conservative $2,000,000. Unfortunately, none of the companies responsible for the discovery and the initial production of natural zeolites made any effort to develop the high volume, low cost applications of this unique mineral raw material. Instead, they developed only the high unit value uses to supplement their existing synthetic molecular sieve product lines. With the producers of synthetic zeolites thinking in pounds and not in tons, further development of natural zeolite deposits stagnated for over a decade.

Jan 1, 1974

It is widely accepted that particles stabilize flotation froths and that stable froths result in improved flotation performance. Predicting the effect of particle addition on froth stability is, however, challenging. Furthermore, there is currently no technique that allows the prediction of the effect of different flotation reagents on froth stability, without carrying out froth stability experiments.

By Summers D. A.

A mining machine has been designed and fabricated to mine coal from room and pillar operations combining high pressure waterjet cutting and mechanical fragmentation. Waterjets are used to slot the coal face with an advancing plow wedge then breaking out larger coal pieces. The machine has the following advantages: - simply built around a disassembled longwall chock and gathering arm loader apron; - few moving parts which are simply and inexpensively maintained; provides immediate roof support in the face working area; - coal produced is larger, with resulting lower preparation cost; - no dust is generated; - risk of spark generation is virtually eliminated.

Jan 1, 1992

By ANDREW HOBERT, Maoming Fan

Low-cost and environmentally friendly green froth flotation modifiers of plant origin, such as guar gum, carboxymethyl cellulose (CMC) and starch, have been used in the flotation of some sulfide and nonsulfide minerals. This paper discusses the fundamentals, current applications and potential new applications of guar gum, CMC and starch in minerals flotation. In this study, improved flotation performance was achieved using some green modifiers in flotation columns.

By T. J. Lutz, S. Gallagher, J. R. Srednicki, J. J. Sammarco

The Illuminating Engineering Society of North America reports that an underground mine is the most difficult environment to illuminate (Rea, 2000). Researchers at the U.S. National Institute for Occupational Safety and Health (NIOSH) Office of Mine Safety and Health Research (OMSHR) are conducting ongoing studies designed to explore different lighting technologies for improving mine safety. Underground miners use different visual cues to escape from a smoke-filled environment. Primary and secondary escapeways are marked with reflective ceiling tags of various colors. Miners also look for mine rail tracks. The main objective of this paper is to compare different lighting types and ceiling tag colors to differentiate what works best in a smoke-filled environment. Various cap lamps (LED and incandescent) and lasers (red, blue, green) were compared to see which options resulted in the longest detection distances for red, green and blue reflective markers and a section of mine rail track. All targets advanced toward the human subject inside of a smoke-filled room to simulate the subject walking in a mine environment. Detection distances were recorded and analyzed to find the best cap lamp, laser color and target color in a smoke environment. Results show that cap lamp, laser color and target color do make a difference in detection distances and are perceived differently based on subject age. Cap lamps were superior to lasers in all circumstances of ceiling tag detection, with the exception of the green laser. The incandescent cap lamp worked best in the simulated smoke compared to the LED cap lamps. The green laser was the best color for detecting the tags and track compared to the red and blue lasers. The green tags were the easiest color to detect on the ceiling. On average, the track was easier for the subjects to detect than the ceiling tags.

Jan 1, 2013

By John W. Brauns

18.1-RAILROAD JOHN W. BRAUNS Conventional railroad haulage can be employed at both open-pit or strip and underground mines-in the latter case, largely for transfer of ore from distant openings to processing plants, or processed material to loading points or docks, using standard hopper cars for bottom unloading or gondolas for rotary dumping. The major application, however, is in surface mining for moving ore and/or waste out of the pit to a crushing plant or dump. Consequently, the following will deal largely with this phase of railroad operation, though the conclusions apply equally, for the most part, to other rail-type surface haulage. In surface mining, trains consisting of a locomotive and gondola or side-dump cars suitable for loading by power shovels are used. Gondolas are restricted to hauling ore as a rotary dumper is required. Side-dump cars are more versatile, carrying both ore and waste, but because of their additional dumping mechanism they are likely to be more expensive to maintain.' Also they weigh up to twice a flat-bottom car of the same capacity and. therefore, fewer" cars can be hauled per train. Standard-gage track is most commonly used. Track systems incorporate low-quality temporary track where moves are frequent and permanent high-quality track on main lines. Rail haulage can be used alone, or in combination with other surface haulage methods, thus permitting a selection best adapted to the peculiar requirements of each mining project. 18.1.1---GENERAL APPLICABILITY, CONTROLLING PHYSICAL CONDITIONS For handling rough rock, the shovel-train system is unexcelled.' The ideal applica¬tion is in a large, but not excessively deep, open pit mine from which the coarsely blasted ore and waste must be transported over 3 mi. If. in addition, a high production rate is to he maintained, railroad haulage probably will afford a lower cost per ton transported. Grade must he relatively gentle-usually 3% uphill and 4% downhill. The greater the differences in elevation involved, the greater are the track grade space requirements; for example, a 3 c ramp out of a pit only 300 ft deep is almost 2 mi long. Main-line track locations should he selected carefully so that the number of moves during the life of the mining operation can he kept to a minimum. This applies both to the ore haulageway and that for waste. Such moves are not only expensive, but are difficult to execute without adversely affecting production rates. The large mine affords greater opportunities for judicious location of semipermanent trackage. Figs. 18-1 and 18-2 illustrate typical track layouts. The effect of terrain in considering railroad haulage is confined chiefly to the initial cost of the installation. Grade construction in mountainous territory is ap¬preciably more expensive. However, if that expense can be borne, the subsequent maintenance cost of trackage will not he much higher than in areas of low relief.

Jan 1, 1973

By R. L. Grayson

As the total cost of labor has significantly increased over the past ten years, older underground mines have found it more difficult to compete- in a limited demand coal market. Many of the older mines were developed extensively into a reserve requiring a large number of workers to maintain and rehabilitate extensive track haulages and/or belt conveyor systems. Often, a large number of fans were required to maintain minimal airflows in areas where poor conditions and huge leakages prevail. This paper focuses upon problems which beset one such coal mine and projects undertaken to restore it to potential profitability.

Jan 1, 1986

The Global Mining Standards and Guidelines Group (GMSG) is building an international, multi-stakeholder community to advance the availability and use of standards and industry guidelines for the global mining community. Standards and guidelines are key strategic tools for operational excellence, enabling companies to move forward with efficient, innovative operations with reduced risk. Launched in May 2012, the GMSG is the first international center to bring together information, resources and collaborative projects for mining standards and guidelines, in an open, knowledge-sharing forum. The GMSG is supported by five partner organizations providing outreach and helping to guide GMSG activities: the Canadian Institute of Mining, Metallurgy and Petroleum (CIM), the Society for Mining, Metallurgy and Exploration (SME), the Australasian Institute of Mining and Metallurgy (AusIMM), the Southern African Institute of Mining and Metallurgy (SAIMM) and the Surface Mining Association for Research and Technology (SMART). GMSG was formed under the CIM Surface Mining Society, though its mandate extends to include underground mining as well. ?SME is supporting the GMSG as a key international activity to advance the implementation of standards and guidelines in our industry, and to provide a forum for our members to access, and contribute to, projects and information to assist their operations,? said SME Executive Director David Kanagy. ?We see the GMSG as a good example of ways the major mining associations can work together for the benefit of all our members.? The GMSG charter encompasses all standards and guidelines that apply to mining; however, a number of subject areas are now being spearheaded by six working groups, namely: ? Access and usage of data from mobile mining equipment onboard systems. ? Operational safety. ? Situational awareness (namely, a unified equipment operator interface). ? Underground operations. ? Asset management and operations data definitions and KPIs. ? Energy in communition.

Oct 1, 2013

By Takuya Tani, Tomoyuki Aoki, Kazuo Saskai

"The authors have proposed a unique methodology in the evaluation of rock mass stiffness for the range of five to twenty meters ahead of the tunnel face, with the use of small diameter inclinometers. The inclinometers are installed at the tunnel crown at a pre-determined constant interval, about one meter behind the face in order to obtain the slight change in inclination angles during tunnel excavation. This method was developed as a daily control measurement such that the geological condition and its possible change ahead of the face could be detected early by monitoring the trend of inclination angles. This paper describes the results of the ground stiffness ahead of the tunnel face evaluated at a mountain tunnel construction site. This stiffness is evaluated automatically and displayed visually by the current system equipped with a result display screen, together with a warning message against a weak zone when detected. 1. INTRODUCTION In a conventional planning of a mountain tunnel, according to the Japanese Standard (JSCE, 2006) seismic refraction surveys from the ground surface are performed and tunnel support patterns are then designed based on the seismic wave velocity. The resolution of the velocity profile estimated by this technique, however, is poor as the tunnel overburden becomes large. The tunnel face is therefore often encountered by unforeseeable fault zones or weak rocks. Such an unpredictable weak zone occasionally causes the collapse of the tunnel face. Clarifying the forward geological information during excavation is hence significant for safe and well-controlled construction. According to the geological conditions ahead of a face, auxiliary methods typified by forepiling and face bolting could be preliminarily prepared for prompt execution. For the purpose of acquiring forward geological information, pilot borehole drilling and seismic reflection methods represented by the TSP (Tunnel Seismic Prediction) or HSP (Horizontal Seismic Profiling) are often applied. Those exploration are carried out near the tunnel face for a couple of days. This often leads to the interruption of excavation procedure and has no small effect on the construction schedule. On the other hand, some forward ground prediction methods in the daily control measurement have been developed e.g. by Schubert et al. (1995). In this method, tunnel displacements in the direction of the tunnel axis are used together with the crown settlements. We have tested their method at a few of our tunnel projects and found difficulty in the evaluation of the forward ground condition due to insufficient resolution of the axial displacement measured by a total station theodolite that we usually use for the tunnel measurement. We have therefore developed a novel methodology of monitoring slight inclination at the tunnel crown near the face, so that the forward ground conditions can be predicted and evaluated as part of a routine measurement procedure."

Jan 1, 2016

By P. G. Semple

For the last four years, the Kilborn Group of Companies (Kilborn) has been involved in several major projects in the CIS. These projects include the Kumtor Project, the Kubaka Gold Project, the Kazgold Project, the Aginskoe Project and the Jerooy Project. These projects are all in various stages of detailed engineering and construction. In this paper, Kilborn will discuss our experience in the CIS and share some insight into project development in this geographic region.

Jan 1, 1996

By W. A. McKinney

The U.S. Bureau of Mines, Kennecott Copper Corp., and New Mexico Institute of Mining and Technology are cooperating on a research project to improve extraction of copper from previously leached waste dumps that are in part compacted and impervious to leach solutions. The field work is being done at the "J" leach dump, Chino Mines Division, Kennecott Copper Corp., Santa Rita, N. Mex. The laboratory percolation leaching tests were made at the U.S. Bureau of Mines Salt Lake City Metallurgy Research Center on drill core samples from the "J" dump to determine how much copper might be leached if permeability could be restored by explosive heaving or other means. The core samples from nine drill holes on "J" dump contained from 0.06 to 0.14 percent copper. Copper extractions ranging from 15 to 3 percent were obtained in 75 days by percolation leaching of minus-1-inch material with dilute sulfuric acid. The tests results indicate that about 2'7 percent of the copper remaining in the "J" dump could be extracted under ideal leaching conditions.

Jan 1, 1970

By Celeste Powell

Liquid carbon dioxide can be used as a replacement for organic solvents in the extraction of anionic PGM complexes from an aqueous phase. This can be achieved only if highly carbon dioxide-soluble chelating agents are developed because conventional chelating agent-metal complexes, such as trioctylamine-gold chloride, are not soluble in liquid carbon dioxide (although trioctylamine is CO,-soluble). Our novel CO,-soluble chelating agents have a fluorinated tail and a conventional amine head group. Both the chelating agent and the chelating agent-metal complex are soluble at ambient temperature at pressures between 7-35 MPa. Equilibrium constants in the 105 range have been measured (in Freon 113, a low pressure screening liquid for carbon dioxide), indicating that these compounds will strongly bind the metal chloride. For example, 93% of Pt-chloride was extracted into Freon 113 using a 3.5:1I ratio of a double-tailed fluoroalkyl amine chelating:metal chloride. 88% recovery of Pt-chloride into liquid carbon dioxide was achieved using the same chelating agent at a 3.5:1 ratio.

Jan 1, 1999