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By Hamid Maleki

This paper reviews a study conducted for Australian Coal Research Limited (ACARP) to assist Anglo-American operations with better understanding of coal burst mechanics and control based on U.S. practical experience, investigations, and inspections in three major U.S. coalfields over the past 45 years. The study examined both nonviolent and burst-prone case studies to identify contributing risk factors and addressed failure mechanisms for major U.S. coalfields in Utah, Colorado, and Kentucky, which have diverse characteristics. To investigate the mechanics of coal burst, a multipronged approach is used. First, field measurements in three mines from East Mountain, Utah, are complemented with finite-difference stress analyses to address the importance of horizontal stress in coal pillar mechanics of violent failure. Second, the computational procedures for estimating seismicity resulting from slip along geological discontinuities are reviewed, as these measurements point to seismicity being the trigger mechanism for violent failure of marginally stable structures. This joint-slip seismicity mechanism is in agreement with the more recentimproved re-examination of mining-induced seismicity (MIS) data from the Crandall Canyon Mine, Utah by University of Utah (UOU). Third, a hybrid statistical-analytical methodology is applied for identifying significant factors affecting coal burst. It utilizes data from 30 case studies including those from Utah, Colorado, Kentucky, and other eastern U.S. mines. The statistical approach reinforces field measurements and points to strata rigidity, joint spacings, and horizontal stress field as significant factors affecting damage resulting from coal bursts. This provides practical capabilities for identifying operations of higher risk using a rigidity-cavability variable. Overall, the study provides valuable insights into the mechanics and risk factors associated with coal bursts in major U.S. coalfields. By utilizing a multipronged approach that incorporates both field measurements and statistical-analytical calculations, the study offers practical capabilities for identifying operations of higher risk and improving coal burst control.

Jul 1, 2023

By Julio C. Martinez, Jeffrey L. Rice, Hayden Weschler

This paper details the extensive underpinning required to hold up the 39th street Bridge while demolishing its massive support piers and building a 30ft deep Cut/ Cover RR tunnel beneath it. The underpinning/SOE support required the construction of 16 large hand dug pits 36ft deep that were reinforced and concrete filled. In addition, an extensive steel support system was tied into the bridge super structure. All of the underpinning/tunnel construction was done while a 110ton crane sat directly atop the heavily trafficked – 66 ft. wide bridge. The tunnel excavation, concrete lining and final bridge pier support work will also be presented. All work was done within 5ft of active mainline tracks and that required tight grouting behind all lagging to eliminate any track settlement.

Jun 13, 2021

By Veerendra Singh, NILAMADHABA SAHU, ARIJIT BISWAS

Manganese alloys are important raw materials for steelmaking. However, selective mining of high-grade manganese ore resources has resulted in a scarcity of these high-grade Mn ores (Mn: >42; Mn/Fe: >5). The present research work is carried out to explore a new smelting reduction process to produce high-Mn/Fe syntheticMn ore from low-grade ferruginous manganese ores. Representative samples of low-grade ores (Mn: 25–30%; Mn/Fe: ~1) were collected and smelting reduction studies were carried out using variable smelting power (20–30 kWh), carbon rate (10–20% of ore) and slag basicity (0.1–0.3) to produce high-MnO slag and manganese pig iron. Studies have shown that different-grade high-MnO slags (MnO: 38.57–58.24%; Mn/Fe: >15) and manganese pigs (Mn: 5.16–24%) can be produced at optimum process conditions. The high-MnO slag can be used as synthetic ore for the ferroalloy production process. The developed process is capable to effectively segregate the iron and manganese in the metal and slag, respectively. The optimum Mn and Fe separation (>95%) was achieved by smelting of 10 kg Mn ore batch in a 50-kVA electric arc furnace using 30 kWh smelting power and 0.16 kg of coke. The slag basicity was maintained at 0.3 and the optimum slag SiO2 was ~30%. The studies indicated that the upgrading of low-grade ferruginous manganese ores is a promising solution for achieving high-Mn/Fe-ratio synthetic ores for ferroalloy production. It can help the manganese alloy industry to overcome challenges associated with the scarcity of high-Mn/Fe-ratio Mn ores and efficient utilization of low-grade resources.

Aug 3, 2020

By S. K. Kawatra, J. A. Halt

"Low-grade iron ores are finely ground and processed to recover iron-bearing minerals. However, the iron-rich powder is too fine to be used directly in blast furnaces and most direct reduction furnaces, and must be agglomerated or pelletized into a usable product called “pellets.” Bentonite clay has traditionally been used as a binder to make iron ore concentrate pellets, but it is expensive and contaminates the pellets. Organic binders may be a viable alternative to bentonite clay. This manuscript reviews organic materials that have been used to make iron ore concentrate pellets. Included are discussions on the development of organic binders, common pros and cons to organic binder use, organic binder structure and its effects on agglomeration, and additives to organic binders.IntroductionIron ore agglomeration turns finely disseminated, low-grade iron ores into a usable product, called pellets. During pellet production, fine-grained, iron-rich minerals are liberated from low-grade ores, concentrated, and agglomerated into round balls that are thermally hardened or cold-bonded to form pellets. Pellets are then transported to blast furnaces or direct reduction operations where they are used to produce iron; iron is further refined and shaped into the wide variety of steel-based industrial and consumer products in use today.Over the years, pellet production has become increasingly more prevalent with the increased exploitation of low-grade iron ores and increased iron and steel consumption around the world. In 2010, world iron ore pellet production was 388 Mt. It could be argued that the current pellet production process has been enabled by the use of binders – practical experience has shown that it would be nearly impossible to agglomerate iron ore concentrates using rotary drums and discs without using a binder."

Jan 1, 2015

By Rainer Antretter

The city of Garmisch-Partenkirchen in southern Germany is located at a main transit road to Tyrol in Austria and suffers of a very heavy traffic load. Therefore, the Kramertunnel as a by-pass tunnel is built to release/mitigate the traffic through the city centre. The 3,600 m long single tube road tunnel is designed with a parallel but smaller emergency tunnel and with cross passages, fitted with single- and doublesided emergency bays, a vent shaft, and an intermediate ceiling to separate fresh air supply from the road traffic. The tunnel, concrete lined along its entire length provided the challenge to find smart formwork solutions for quick set-up, repositioning, setup and pouring. Three particularly specific sections are discussed in this paper.

Jun 13, 2023

By Ronald M. Hays

The White Pine Copper Division of Copper Range Company is a large copper producer operating an underground mine, mill, and smelter on Michigan's Upper Peninsula. Principal water discharges are from the tailings basin where these discharges are high in dissolved solids because of mine water pumped into the basin. Principal air emissions are from the smelter where SO2 emissions are uncontrolled. Although water discharges and air emissions have not had significant environmental impacts, environmental regulations could require additional control procedures. Because of low copper prices and poor profitability, cost of compliance with possible new environmental regulations could have serious impact on White Pine with no apparent significant beneficial environmental impacts.

Jan 1, 1979

By P. Eger

Minnesota contains a major low- grade copper-nickel sulfide resource within the Duluth Gabbro Complex. Several companies have actively explored this resource. Open pit mining would be required to develop portions of the resource, and as a result, large quantities of sulfide-bearing lean ore and waste rock would be stockpiled. Although the problems associated with high-sulfide tailings and acid mine drainage are well documented, the leaching characteristics of low-grade mineralized stockpiles must be understood for environmental impact assessment, siting, and planning. The Minnesota Department of Natural Resources and AMAX have cooperated in a research program to study leaching and revegetation -of test stock- piles, Six small (1600 'tons) stockpiles were constructed at the MINNAMAX Project Site and they range in composition from 0.29 to 043 g % copper, 0.075 to 0.09% nickel, and 0.6 to 1.45% sulfur. Two of the stockpiles were covered with mineral soil, one was covered with topsoil, and three were not treated Revegetation plots were established on the piles which received a soil cover. Leachate samples and flow measurements were collected at the base of the piles. Initial results indicate that metal concentrations in leachate samples range from 10 to 10,000 times the concentrations found in the streams of the area. During the first growing season, the test pile covered with topsoil yielded 30% less water than untreated test piles. No reduction in yield was observed for the piles that were covered with the less fertile mineral soil. First-year vegetative growth, expressed as biomass, was four times greater on the-topsoil pile than on the mineral soil piles. The long-term effects of vegetation on leachate quantity and quality continue to be investigated.

Jan 1, 1980

By R. B. Toombs

In describing the Canadian mineral industry in a world setting, this paper examines the industry from four points of view. First, mineral industry growth is related to trends in economic activity thereby providing a measure of the industry's importance in the Canadian economy. To give perspective to the Canadian scene, reference is made to economic trends in several of the world's leading mineral producing and mineral consuming countries. The Canadian mineral industry is next examined in terms of its major developments of the past 20 years and the resultant size, structure, and production diversity of 1964. The position of the Canadian mineral industry in the world industry is then analyzed by tracing changes in mineral supply and demand patterns. Growth of the Canadian industry depends greatly on expansion of export markets because three fifths of the value of production is accounted for by exports. Finally, attention is directed to the outlook for the Canadian mineral industry. Problems facing the industry are surveyed, and an appraisal is made of economic policies that have encouraged industry growth. A forecast of mineral production value in 1970 is included.

Jan 1, 1964

By N. Iverson, E. Haft, V. T. McLemore, M. Woodard, E. Owen

Present and emerging technologies are renewing interest in domestic rare earth elements (REE) production. REE deposits throughout the North American Cordilleran alkaline-igneous belt are being re-examined for their economic potential. In New Mexico, the mineral deposits found in this belt are associated with Eocene–Oligocene alkaline to calc-alkaline igneous rocks. Four areas in New Mexico have been examined for their REE potential. The chondrite-normalized REE patterns are similar for all four districts, even though different REE minerals are found. Crandallite, xenotime, bastnäsite and brookite are found in fluorite veins and carbonatites at Laughlin Peak. Bastnäsite was extracted during fluorite processing from 1954-1980 from the Gallinas Mountains, where samples as high as 8% total REE are found in fluorite veins. Other REE minerals include agardite, parasite, xenotime, and monazite. Allanite, thorite and as much as 8133 ppm total REE are found in fluorite veins in the Capitan Mountains. In the Cornudas Mountains, exploration along the outer edge of the Wind Mountain nepheline syenite laccolith and within phonolite dikes, plugs, skarns and carbonate-replacement deposits in Chess Draw contain as much as 3110 ppm TREE, hosted in eudialyte, monazite, bastnäsite, and calciocatapleiite.

Feb 1, 2023

By J. G. Craig

This paper initially was to be on the design, construction and operation of the Lucky Friday mill. However, this subject has been pretty well covered in some of the mining publications in the past few years - specifically Mining Congress Journal for April, 1961 and Mining World for March, 1962- : In order to avoid too much repetition, we decided to present in this paper a comparison of the Lucky Friday mill constructed in 1959, and the Mayflower mill built by us in 1962. During the past three years Hecla Mining Company has constructed two relatively small mills: The Lucky Friday mill at Mullan, Idaho 750 T/day; and the Mayflower mill at Heber, Utah - 450 T/day. These mills were engineered, designed and constructed by Hecla, using principally our own personnel, with very little outside (contractor) labor employed. This paper presents a comparison of some of the interesting features of these mills, and where differences occur, it discusses the reasons for the various differences. It compares such points as the testing program, physical layout of the plant, construction costs, the grinding section, the flotation section, tailings disposal, metallurgy, recovery, grades, operating costs, etc. To help illustrate, and to compare these features, we will project pairs of slides showing each of the two mills. First a little background and history on the properties ---

Jan 1, 1964

By G. Pan

Although geostatistical techniques have been widely accepted as the standard methods for reserve calculations in the mining industry, the production data of many mines frequently differ from geostatistical estimations based on exploration and development drilling. The discrepancies in recovered metal amounts, commonly in the range between 10% and 30%, are related to different factors. Major causes vary from mine to mine. A common cause, however, is the ignorance of important geological constraints in reserve modeling. Three major factors appear to be related to such an unfortunate fact: 1) modelers are over-confident on geostatistical techniques, 2) it is difficult to establish geological models, and 3) mine schedules are too tight to allow detailed geological modeling work. Defining mineralization envelopes has been a major effort in geological modeling. Past experiences have showed that geological modeling is much mo~ demanding than the choice of sophisticated kriging estimators. Since building envelopes for complex ore bodies can be extremely tedious and time-consuming, computerized approaches are badly needed for mine modelers. A comprehensive procedure reported here is referred to as probability-assigned constrained kriging (PACK), which includes a built-in method for defining 3-d mineralization envelopes. The modeling technique is fast and accurate for complex precious metal deposits. The technique is demonstrated on a gold deposit. The estimation results are compared with blast-hole based production panels, showing that the estimated tonnage is 2.2% larger than the actual production and the average grade is 2.6% lower.

Jan 1, 1994

By Valérie J. Bertrand, Richard W. Lawrence, Marcos G. Monroy

Two cemented paste backfill (CPB) formulations containing pyritic tailings were leached in deionized water in flooded and alternating air-flooded environments and in a simulated acid rock drainage-type (ARD) solution. Scanning Electron Microscopy (SEM), solid phase chemistry and acid-base accounting measurements documented the weathering characteristics of the CPB samples. Short-term exposures of the portland-CPB samples preferentially dissolved the cement binder to a greater extent than slag-Portland CPB mistures. In all cases, the added neutralizing potential provided to backfill by cement was short-lived and insufficient to neutralize the acid generating potential of the mixture.

Jan 1, 2000

By Y. C. Kim

This paper describes the implementation aspect of a blast hole kriging system which has been developed for the purpose of daily ore-waste control in an open pit mine. The primary goal of blast hole kriging is to improve the ore-waste delineation procedure. A complete computer program package called Blast Hole Kriging (BHK) System was developed for IBM/PC AT or XT computer, using Fortran language and supplemented by a few Assembly language routines for bit-map manipulation. The emphasis of this paper is on the implementation aspect of the developed system. For this reason, the requirements for practical implementation and the system design considerations are discussed in the paper, as well as the main features of the University of Arizona's BHK System.

Jan 1, 1990

By I. Demers, A. Blier, M. Mbonimpa, M. Benzaazoua, B. Bussière

The Doyon Mine in Quebec, Canada, evaluates the possibility of desulfurizing its tailings to produce material to be used as cover for the acid-generating tailings disposal site. Laboratory tests showed that a single-layer cover made of desulfurized tailings placed over reactive tailings can prevent the generation of acid mine drainage. Modeling with the software Vadose/W was used to optimize the design parameters, namely, cover thickness, water table position and residual sulfide content of desulfurized tailings following laboratory work. It was found that the optimal configuration includes a 1-m (3.3-ft) desulfurized tailings cover containing 0.8% S, with the water table kept at the interface between the reactive tailings and the cover. To maintain the cover performance to reduce oxygen flux toward acid-generating tailings even in the event of a long dry period, a sand layer is suggested to protect the cover from excessive evaporation. It is possible to reach the environmental objective for oxygen flux chosen for the Doyon Mine (10 mol/ m2/year) with the protective sand layer, even in extremely dry conditions.

Jan 1, 2009

By Allan G. Provost

Shaft construction is assuming ever increasing importance when new mining enterprises are considered. The reasons for this increased emphasis is the much greater depths at which many new ore-bodies are being developed and the rapid depletion of near surface reserves requiring mines to go to greater depths on existing deposits. These greater depths increase the probability of exposure to unfavorable geologic conditions and it is more likely that high ground and/or water pressures will be experienced at these depths. The large capital costs involved and the critical position of a shaft in the overall mining program necessitate that this element of project development be given careful and critical consideration. The Henderson No. 2 Shaft is located in the Rocky Mountains of north central Colorado (See Figure I), about 55 miles west of Denver, near the community of Empire in Clear Creek County. At the 10, 442 foot collar elevation, winter arrives in late September and brings snow to contend with until May. The labor force for Shaft No. 2 is approximately 90 men. They are provided access to the project via all-weather U. S. Highway 40. SHAFT DESIGN The Henderson No. 2 Shaft is a 28-foot I. D. circular, concrete lined (1 foot thick) vertical shaft. The final depth will be approximately 3100 feet

Jan 1, 1972

By K. S. Radcliffe

Results are presented for the first phase of an experimental program to study the feasibility of using acoustic velocity for predicting the state of stress in a rock mass. Compressional wave velocities were determined axially in cylindrical samples during uniaxial compression for several rock types conditioned in dry and water-saturated environments. Results indicate that in rocks containing compressible voids or cracks, substantial velocity change occurs with the application of stress in the lower (below 100 MPa) stress regime. The effect norm- ally is nonlinear, however, and diminishes to asymptotic values when cracks or voids become closed or with saturation. Empirical prediction equations were derived for each rock type by linear and nonlinear regression analyses, and correlation coefficients were calculated to determine the equations that best fit the stress- velocity data. The operational range for predicting stress using compressional-wave velocity appears to be within the range of vertical stress expected in most shallow to intermediate depth mining operations (less than 1,000 m). Based on the experimental results to date and theoretical considerations, it appears that the technology can be advanced to predict in situ stress based on acoustic P-wave velocity determinations in most mining situations.

Jan 1, 1986

Contents

Jan 1, 1985

By George Hope, Edward H. Smith

In late 1989, LAC Minerals purchased 65% of Bond International Gold and as a result became controlling shareholder of the El Indio Mine through Bond and San Jose. El Indio is a world class, complex sulphide gold deposit located in the hydrothermal alteration belt of the Andes mountains in the 4th Region of Chile. The mine is located in the high Andes about 185 km east of La Serena at an elevation of 4000 meters. The 1450 workers at El Indio live in the mine camp at 3200 m and on days off are bussed to La Serena. The El Indio mine was started in 1979 by St. Joe Minerals Corp., bought by Bond in 1987 and subsequently by LAC in 1989. The mine has produced 2.7 million oz. of gold, 9. 5 million oz. of silver and 170,000 t of copper since start of operation. The mill is currently operating at a rate of 2850 t/d and producing a copper/gold concentrate which is roasted to produce a copper/gold calcine and high quality, saleable crude As203• A small proportion of the precious metals are also produced as bullion from the leach circuit. Total production during 1989 was 224,197 ounces of gold, 1,309,342 ounces of silver and 26,968 tonnes of copper. The average cash cost of production for the period was U.S. $96 per ounce of gold, net of by-product credits. The average realized price was $5.30 per ounce of silver and $1.14 per pound of copper.

Jan 1, 1990

By Y. H. Zhan

A new P(MAAA) latex was developed and used in separation of ultrafine apatite from calcite and silica by means of selective flocculation. The latex was found to flocculate selectively apatite from apatite/calcite and apatite/silica mixtures in the presence of sodium tripolyphosphate and sodium silicate over a pH range from 9.1 to 9.4. The separation of apatite from calcite was more selective with sodium tripolyphosphate, while the results of the separation of apatite from silica were better when sodium silicate was used. In the apatite/calcite system, 90% apatite recoveries into a concentrate containing 34% P2O5 were possible in the presence of 4 mg/l of sodium tripolyphosphate at a latex dosage of 2.2 kg/t. In the apatite/silica system, 80% of apatite could be recovered into a concentrate containing 33% P2O5 in the presence of 20 mg/l of sodium silicate at a latex dosage of 1.1 kg/t. Deposition tests were used to study the interaction between the latex and the mineral surfaces. The results revealed that deposition density of the latex on apatite was higher than on calcite; the differences between the deposition onto these two minerals were higher at pH 9.2 than at 7.2. The results point to the stronger interaction between the latex and apatite surface when compared with the latex-calcite interactions.

Jan 1, 1998

By Alexander Darío Huamán Ccorahua, Cayo Fernando Soto Buendía, Jhonatan Raphael Rojas Ventura

Lithium is a top-quality mineral in the energy market, with growing demand. It has many applications in medical, nuclear, and energy industries. The purpose of this article is to quantify and analyze the economic potential and projected global demand for lithium annually. It aims to determine Peru’s (specifically Puno) positioning in the global context in 2025 and 2030. The article also seeks to identify the main regulatory, environmental, and social challenges to sustainably exploit lithium in Peru. The study employs applied research (mixed approach), descriptive-correlational scope, and observational, crosssectional design. The methodology demonstrates the use of statistical techniques to model and make predictions about this energy-transition metal. Academic sources were reviewed to enable a comparative approach and projection into the future of lithium for development in the mining industry. In the last 10 years, lithium demand has grown, noting a 600% increase in the economy and projected annual growth of +26%. Exponential growth in resources is projected, where econometric, R-multivariable and R-linear models estimate that Peru could supply 1.5% in 2025 and 3% in 2030 of global lithium. Estimated growth of 5–15% in socio-environmental conflicts is projected with the start of lithium exploitation (Peru – Puno). The global potential of lithium demonstrates exponential growth. Lithium reserves in Puno - Peru would rank 13th between 2025 and 2030. It is necessary to establish a clear regulatory framework to avoid excessive increase in socio-environmental conflicts.

Feb 1, 2024