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By W. C. Dailey

The Groveland Mine. Concentrator and Pellet Plant are located in Dickinson County in the Upper Peninsula of Michigan. The construction of the Groveland Mine in 1959 was the first United States operation for the Hanna Mining Company in mining and beneficiating low grade iron formations. (1) The plant produced concentrates at 675,000 lt/yr. (746,600 mt/yr.) which was used as sinter feed in the steel industry from 1959 to 1963. Upon completion of a pelletizing plant in April, 1963 production increased to 1.6 million lt/yr (1.77 million mt/yr) of pellets. After the plant expansion, mill capacity increased to 2.2 million 1t/yr (2.43 million mt/yr.), producing 2.0 million It/yr (2.23. million mt/yr.) of pellets assaying 63.0% iron and 7.0% silica. (1) Prior to April, 1971 the concentrator operated with a flowsheet consisting of spirals and a petroleum sultonate iron notation circuit. This was presented in a paper by R. R. Smith and E. E. Sougstad, "Flotation at the Groveland Mine" in the 50th Anniversary Volume entitled "Froth Flotation". The ore body at the Groveland Mine consists basically of two types of iron formation (34% total iron, 20% magnetic iron head), the most abundant of which is a bedded magnetite-chert-silicate rock. This is intermingled to varying degrees with non-bedded to poorly bedded hematite-clastic quartz-chert rock. (1) In developing the Groveland flowsheet, Humphrey spirals were used because of their ability to produce a coarse size concentrate at a low cost. Tests run in the lab and pilot plant on the Groveland ore showed a. spiral weight recovery in the 27 to 33% range. (2) However as the ore body was opened up, it became evident that the most abundant ore type did not liberate at the coarse size fraction needed for spirals. Plant recoveries for the first five years operating the spirals only averaged from 10 to 15% weight recovery. In 1971 the weight recovery on the spirals had dropped to a low of 5%. To increase iron recovery and at the same time increase plant capacity with the least effect on the present operations the mill flaw-sheet proceeded from a spiral-notation circuit to an all flotation circuit to a magnetic separator-flotation circuit. During this changeover the concentrate grade also had to be improved to meet market demands. To do this the following changes evolved

Jan 1, 1978

By Jonas Svensson

The Grangcold Pellet Process - for which patents have been applied or already granted in a number of countries - uses a hydraulic adhesive such as Portland cement, slag cements, pozzolanic cements, etc., for the production of cold bonded pellets. The idea of using a hydraulic binder for the agglomeration of iron ore fines is not new. Portland cement was proposed as an adhesive for cold bonded iron ore briquettes in patents granted more than 50 years ago (1). In a report on the briquetting of iron ore fines, published in Stahl and Eisen 1959 (2), it is stated that briquettes bonded with Portland cement are used on a small scale at on ironwork in Germany. According to the report, the briquettes showed excellent strength in the blast furnace although their general use was made impossible because they required a long hardening time, during which they are sticky, soft and difficult to store and handle. The Grangcold Pellet "recess has overcome this particular disadvantage by mixing the balls with a suitable amount of the balling concentrate before storing them. The pellets are embedded in the concentrate during storing in such a way that they are isolated from each other and thus prevented from sticking together to form clusters. Thanks to the embedding concentrate, the pellets are subjected to a more or less uniform pressure from all sides which does not deform them. Thus the mixture can he stored in a stockpile or in a silo until the pellets have hardened sufficiently. The concentrate is separated from the pellets by means of screening. The concentrate is returned to the balling operation and the pellets are either shipped to the blast furnace or stored for final hardening.

Jan 1, 1969

By D. F. Boyd

On April 10, 1958 a new 7500 long ton/day iron ore beneficiation plant went on stream producing an average of 3000 long-tons of high quality concentrate a day. Plant operates on two, 12-hour shifts is six days per week, The new mill end crust ink plant were built adjacent to the company's open pit dining operate on at Bomi Hills, Liberia. The mall is essentially a gravity concentrator employing crushing, and grinding to liberate the mineral values, followed by concentration in Humphreys spirals. The cleaner spiral tailings are re-ground and tabled to recover additional iron values. Ire addition to. this mills the company operates a crushing and screening plant for the high grade direct shipping ores

Jan 1, 1962

Projections of coal reserves in Central Appalachia are essential for long-term planning in the region. Annual production is declining in some states, such as Virginia, and mineable reserves for the Central Appalachian Coalfield are challenged by difficult geological, mining, and market conditions. In order to project coal mining longevity in this region, interviews with mining companies were conducted to assist in the determination and assessment of technical and economic factors that impact coal seam mineability. This information was applied to seam and coal reserve data developed by state and federal governments. The results were carefully analyzed to determine the effects of various factors on the overall mineable coal reserve base.

Jan 1, 1998

By Christopher Hebert, Michael R. King, Mehdi Ghazi

The Inland Feeder project is a critical component of Southern California’s water delivery system, relying on a strategic plan of water transfer and storage to enable the delivery of an additional 650 million gallons of water a day. The Arrowhead West and Arrowhead East tunnels form part of this system, comprising the construction of nearly13 km (8 miles) of bored tunnel under the San Bernardino National Forest. This paper describes the design and manufacture of the 4.88 m (16 ft) diameter precast segmental primary lining that will be used in these tunnels to resist rock loads, and up to 275 m (900 ft) of external hydrostatic head.

Jan 1, 2003

By S. Tafazoli, N. Himmelman, D. Chan, E. Chow

"While Wearable Technology has been garnering attention in the consumer market, enterprise and industry have just begun exploring its potential applications. Since February 2014, Motion Metrics International has been working in collaboration with Vandrico Solutions Inc. to apply Wearable Technology to improve productivity and safety in the mining industry. This paper discusses the value proposition of using Wearable Technology to deliver critical notifications in mining. The advantages and disadvantages of various form factors are explored. The challenges, both specific to mining and in general to Wearable Technology, are defined. Finally, the concept of MetricsGear™, the first Wearable Technology platform developed for mining by Motion Metrics International in collaboration with Vandrico Solutions Inc., is described. MetricsGear™ is designed to notify the user with minimal distraction to keep the user focused on their primary task, and aware of mission-critical events. This focus and awareness allows the user to work more efficiently and safely. INTRODUCTION The mining process consists of a series of intricate stages, where certain events or conditions in one stage can have a huge impact on other stages. The notification of these critical events or conditions is vital for ensuring the overall efficiency of the mining process. Critical notifications can be classified as two types: time-critical events and contextual information. Time-critical events are situations where a timely response from a responder can have a significant impact on seizing an opportunity or mitigating cost. Some Human-Computer Interaction (HCI) experts classify notification types based on the Interruption, Reaction, and Comprehension (IRC) framework. Time-critical events are classified to have high interruption, high reaction, and low comprehension due to their urgency. The responder should have just enough information to identify the crisis and react as soon as possible (Chow, E. 2014). For example, when a tooth is lost during shovel operation, it is necessary to recover the missing tooth before it jams the primary crusher. The consequence of missing this critical time period is a jammed crusher that can cause the mine to be out of production until the jammed tooth is extracted (Baumann, M. 2013). In this case, the responder only needs to see an image to confirm if the tooth is missing, and information to identify which equipment and when the tooth went missing (see Figure 1). Contextual information is relevant information that is valuable for the receiver to be aware of as it can present an opportunity to improve efficiency or save cost. According to the IRC framework, contextual information is classified as low interruption, low reaction, and high comprehension. They are not as urgent as time-critical events, but provides more detailed and informative information to assist the receiver. For example, when a shovel’s worn tooth is predicted to require replacement soon, a notification to a GET technician can help him or her schedule a pre-emptive replacement of the tooth in an already planned maintenance to prevent having to reactively schedule another one when the tooth is critically worn. This helps reduce the amount of equipment downtime to maximize production (Baumann, M. 2013). In this case, the receiver will look at the information when he has a moment to spare to get a quick forecast, and make use of this information as needed (see Figure 2)."

Jan 1, 2015

By C. Heckman, M. S. Moats, A. Luyima, W. Cui

"Nucleation and growth of copper on 316L stainless steel from synthetic acidified copper sulfate was studied in the absence and presence of chloride ions and/or organic additives (HydroStar® 4208, DXG®-F7, Cyquest® N-900) using a potentiostatic technique. The current-time data obtained at 0.16V vs. SHE was analyzed using nucleation and growth models. Scanning electron microscope (SEM) images of deposits produced at 300 A m-2 show that the addition of 20 mg/L chloride ions increased the size and reduced the number of copper nuclei. Potentiostatic current-time data from the electrolyte without organic additives indicate progressive nucleation with two-dimensional (2-D) growth under diffusion control. SEM images obtained confirmed progressive nucleation with 2-D growth. 20 mg/L Cl- and 2.5 mg/L organic additives did not change the nucleation and growth mechanism, however the additives increased the number and reduced the size of copper nuclei leading to more uniform coverage of the stainless steel substrate.INTRODUCTION Electrowinning of copper is an important process in the manufacture of high purity copper metal. It is approximated that 20% of the world’s refined copper is produced from acidified copper sulfate solutions by electrowinning (Schlesinger, Sole, and Davenport, 2011). In many plants, copper is electrodeposited on AISI 316L stainless steel substrates for a period of 6-7 days, after which the copper is stripped from the blanks. Even though the deposition time for a commercial copper electrowinning circuit is around one week, it is critically important to control the nucleation, growth, and nature of the initial deposit (Sun and O'Keefe, 1992). Deposit morphology and structure are influenced by the real current density at the electrode surface. The real current density across the cathode surface is made uniform by proper design of the electrowinning cell and electrodes and careful operational practice. Even with good design and control, some current maldistribution occurs. The outcome of severe current maldistribution is poor deposits that affect product quality and/or increase energy consumption. To combat current maldistribution and create a larger operating window in terms of current density, temperature, and copper concentration, small amounts of organic smoothing agents (traditionally guar products) are added to copper electrowinning electrolytes. Moreover, these additives inhibit the growth of copper dendrites, which leads to improved deposit quality by producing bright, smooth, and dense cathodes."

Jan 1, 2015

By Brianna Eiter, Max Barham, Tim Bauerle

Fatigue-related risk is a persistent safety concern for the mining industry. However, fatigue and sleepiness are often treated interchangeably, which can lead to confusion and potentially less effective reduction of safety risk. To provide clarity, we present an overview of similarities and differences between work-related fatigue risk and sleepiness including definitions, theories, measurements, and mitigation strategies. As a supplement, a summative visual model which highlights these similarities and differences is presented. Expanding industry knowledge in this area will assist safety professionals in crafting more targeted risk management practices appropriate for work-related fatigue risk, sleepiness, or both.

Dec 19, 2023

By B. Eiter, M. Barham, T. Bauerle

Fatigue-related risk is a persistent safety concern for the mining industry. However, fatigue and sleepiness are often treated interchangeably, which can lead to confusion and potentially less effective reduction of safety risk. To provide clarity, we present an overview of similarities and differences between work-related fatigue risk and sleepiness including definitions, theories, measurements, and mitigation strategies. As a supplement, a summative visual model which highlights these similarities and differences is presented. Expanding industry knowledge in this area will assist safety professionals in crafting more targeted risk management practices appropriate for work-related fatigue risk, sleepiness, or both.

Feb 1, 2023

By Charles B. Escapule

The first successful heap leach of silver ores in the State of Arizona has been under continuous operation since early 1976 at the State of Maine Mine, two miles southwest of Tombstone, Arizona. The silver produced from leaching old mine dumps at this property vas the first in the Tombstone mining district to achieve a 999+ purity. While cyanide leaching of silver and gold ores is a time-proven accepted practice, a relatively new method of treatment called "heap" leaching was employed. Heap leaching is a comparatively inexpensive fast way to recover precious metals from low grade material.

Jan 1, 1981

By Erik Sundström, Magnus Nygren

The study explores the influence and consequences of safety initiatives on the development of safety cultures in the Swedish mining industry. It involves interviews with experts from four mining organizations, highlighting themes such as organizational structures, safety leadership, feedback, and communication.

Nov 1, 2023

By D. J. Frey

While costs of most commodities and services have increased markedly over the past 25 years, the cost of electricity has steadily declined. One of the reasons for this price decline is the improved efficiencies of generating plants which is shown in Fig. 1. 1,2 Another reason for this is the decline in coal production costs. Efficiencies for the best plant increased from about 32 percent in 1540 to about 40 percent in 1962 and then decreased slightly to 38 percent in 1965. The increase in efficiency for all plants (US average) has been even more notable, progressing from less than 15 percent in 1940 to about 32 percent in 1965. The chief reason for the improved efficiency is the change in operating steam temperatures. These increased about 12 F per year until 1200 F was reached in 1962. At this high temperature excessive corrosion of super-heater and reheater tubes was experienced and steam temperatures were dropped back to 1050 F and even 1000 F in some cases. To successfully compete against other energy sources for generating electricity, this corrosion problem must be solved so that operation at higher temperatures and thus, increased efficiencies will be possible.

Jan 1, 1967

By Sai Phaninder Reddy Chaganti, Corrina D. Beaven

This study investigates the effect of reagent type, dosage, and pH on flotation kinetics and copper recovery for secondary sulfide ore with elevated clay content. The primary objective was to determine whether Xanthate performs comparably to or better than the currently used primary collector, Thiophosphate. Approximately 80 kg of ore was collected from three blast holes and systematically prepared through drying, crushing, grinding, and flotation testing. Grinding tests were conducted to establish optimal grinding time and lime consumption for pH control, achieving a target particle size distribution in 13 minutes and 30 seconds. Elemental and mineralogical analyses using X-ray Fluorescence (XRF) and X-ray Diffraction (XRD) identified a copper content of 0.36% and significant clay presence, affecting flotation performance. Fifteen flotation tests were performed under controlled conditions, with variations in reagent dosages. Control tests confirmed reproducibility, with recoveries around 80–82%. Increasing the pH did not improve kinetics or recovery, making higher pH adjustments economically unjustifiable. Adjusting the Thiophosphate dosage yielded the best recovery of 83%. Xanthate collectors, tested both as tertiary additives and as replacements for Thiophosphate, delivered comparable or superior recoveries—up to 91.5% in plant tests—and demonstrated faster flotation kinetics, even under high-clay conditions. These findings highlight Xanthate’s reduced sensitivity to clay, potential for lower dosage requirements, and operational benefits such as improved selectivity and circuit efficiency, validating its role as a cost-effective and alternative for processing complex sulfide ores.

Feb 22, 2026

By Thomas Novak, Sampurna Arya

Controlling dust generation and keeping it below permissible limits to meet federal dust standards at the working face of a roomand-pillar coal mine is a challenge for a mine operator. With the recent changes in federal dust regulations requiring lower worker exposure, maintaining compliance has become increasingly difficult. The current most effective practice of dust control at a continuous miner face in an underground mine is the use of a flooded-bed scrubber. A study carried out by the National Institute for Occupational Safety and Health (NIOSH) indicated that a flooded-bed scrubber could achieve cleaning efficiencies between 58 and 90%. But, the operation of such a system is maintenance intensive. The flooded-bed scrubber screen becomes clogged with dust particles and requires frequent cleaning to maintain performance. However, the dust control issue is not solely a mining industry problem. Other industries face similar issues. The University of Kentucky collaborated with Toyota Motor Manufacturing on the development of a novel wet scrubber, called the vortecone scrubber, for capturing oversprayed paint particles in automotive paint booths. The vortecone scrubber achieved a cleaning efficiency of 99% and required minimal maintenance. This study aims to assess the ability of this vortecone scrubber to capture respirable dust in an underground coal mine. The paper presents the results of computational fluid dynamics (CFD) modeling of this vortecone scrubber. It discusses the effects of air quantity and dust particle size on the performance of the scrubber.

By David L. Shearer

INTRODUCTON James Howden first secured an order for two Service Tunnel Boring machines in November 1986. These Tunnel Boring machines were 5.7 and 5.4 metres in diameter and the full length including back up was 215 metres. Manufacture commenced in December 1986 at the Glasgow factories of James Howden & Company with the deliveries to site of the machines in September 1987 and March 1988 respectively. In December 1987 two further orders were secured for the land running tunnels at 8.7 metres diameter. This paper presents some of the challenges in building tunnel boring machines for the Eurotunnel project between Britain and France. The general specifications of the Tunnel Boring machines and length of drives are shown in Appendix 1. DESIGN PARAMETERS The specification given by the Consortium TML on behalf of their client Eurotunnel cleary indicated that cutting of the face should be concurrent with the building of the precast concrete lining rings. In order to do this a telescopic machine was thought to be the best solution. Ground conditions were described as chalk marls of homogeneous nature with the possibility of friable areas and some revelling. A shielded type TBM with open cutter head was chosen together with a telescopic section and a rear

Jan 1, 1989

By W. P. Blacutt

A financial-economic model incorporating physical, market, and policy variables is developed for mining investment in Bolivia. Additional risk criteria emanating from political instability. new mining legislation, recent environmental regulations, and a new minerals taxation system are accounted for and are integrated into the investment decision model. Results of the model indicate that geologic and market variables have the dominant effect on the investment-worth function. Among policy variables, exchange rate and taxation policies have the most significant influence. Depreciation allowance for infrastructure development has negligible weight in the investment-worth function. The business structure of the firm considering investing in the Bolivian Polymetallic Project is found to be an instrumental factor in the investment-worth outcome. Specifically, undiversified mining companies whose operations exclude zinc production as the primary source of revenue would benefit most from adoption of this project.

Jan 1, 1993

By C. M. Bristow

The mineral kaolinite is one of the commonest minerals in the uppermost 10 m of the continental crust; ranking in abundance alongside minerals like quartz, mica, feldspar and calcite. Only very exceptionally does it possess all the necessary properties needed to make it worth commercially exploiting. The terms 'Kaolin' and 'Kaolinite' are derived from a locality known as 'Kau-ling', in Jiangxi Province, Peoples Republic of China; where samples of a white clay used by the Chinese to make porcelain were first obtained by European missionaries and explorers in the eighteenth century.

Jan 1, 1986

By Martin Valeri

The operation described in-this paper will be confined to the Nemacolin Mine of The Buckeye Coal company, Nemacolin, Pennsylvania.' This mine is-located on the Monongahela River approximately sixty miles south of Pittsburgh. The mining is in the Pittsburgh seam that has an average thickness of 88 to 90 inches. The current practice is to mine approximately 80 inches, leaving 8 to 10 inches of roof coal. All of the coal produced is used solely for by-product coking by the parent Youngstown Sheet & Tube Company, Youngstown, Ohio. Eight to ten inches of top coal are left by the miners to prevent air slacking of the draw slate. In addition, this top coal which will float at the washing gravity has a very high ash and sulphur content, and when mined, seriously affects the quality of the clean coal product.

Jan 1, 1961

I found the article most interesting and timely. I consider it imperative that mine case studies like this one are undertaken and published so that the practicing mining engineer and geologist can obtain a better idea of what is the preferred estimation and grade control technique to use, given the site-specific geology, grade distribution, etc. Mining companies, with operating gold mines, need to be encouraged to either initiate such a study in-house or support a research project by financing a graduate student at a local university. The latter method is preferable since it not only provides research support but also an excellent training opportunity for young mining engineers and geologists. Ideally, what is needed is exploration drill-hole, blasthole, and mine production data that can then be used to assess the efficiency of different estimation and grade control methods by comparing the results obtained using the drill/blasthole data with the actual production data. It is hoped that more mining companies will realize that the rewards from this kind of research greatly outweigh the sometimes perceived problem with releasing data to a university. I noticed that the authors used the blasthole data to represent the actual values, the validity of which relies heavily on the two key assumptions with regards to blasthole assays and in-pit ore-waste selection procedures. Could the authors comment in more detail on these assumptions and what criteria they used to check the validity of the assumptions? Since the article was published, have the authors had the opportunity to compare their estimates with the actual production data? It would be interesting to compare other estimation methods with OK and IK. For example, how well did the polygonal method used at the mine compare with the results given in the paper? I would like to mention that B.L. Kwa completed a similar study (Kwa and Mousset-Jones, 1986) using exploration drill-hole, blasthole, and production data from the Alligator Ridge mine in Nevada. The study compared a variety of estimation methods, including IK, and the final results are shown in Fig. 1. The IK method exhibits the smallest difference between estimated and production results and is closely followed by the indicator moving window (Ind MW) method. Reply by Y.C. Kim We do concur with Professor Mousset-Jones with respect to the merit of such case studies performed at a local university. In answer to his request for comment on the validity of the two key assumptions made in our paper, we can only say that these are reasonable assumptions that are very difficult to validate. The assumption of blasthole assays being accurate can be partially validated by a careful analysis of the nugget component of blasthole variograms. The assumption that the in-pit ore-waste selection procedure in use was an effective one can only be validated through comparison between the mine estimates of ounces of gold versus the actual recovered ounces of gold at the mill. Neither one of these two assumptions has been validated to date due to several reasons. For example, the mine went through a change in management since the study. Similarly, no compelling reasons have been presented to perform detailed variogram analysis of the blasthole data. We do, however, believe that the obtained results (i.e., indicator kriging performs better than OK in a highly skewed deposit) will remain the same in relative terms, regardless of how valid these two assumptions may be. The most recent com¬parative study by D. S. Lindsey of the Montana College of Mineral Science and Technology also shows a similar ranking between ordinary kriging versus probability kriging, which is an extended version of indicator kriging.

Jan 1, 1987

By Gregory M. Rumbaugh, Todd Kostecki, Christopher Mark

From 2015 to 2021, five massive pillar collapses occurred at four underground stone mines in the eastern United States. These events resulted in powerful airblasts that damaged mine infrastructure and mobile equipment, seriously injured miners, and disrupted underground travelways. Each of these pillar collapses propagated through the overlying strata, causing a subsidence basin on the surface. Pillar collapses are particularly hazardous for miners because they can occur with little warning and can affect miners that are far from the pillar collapse area. The following case studies show that certain factors may increase the likelihood of a pillar collapse. For instance, each of the five events involved the collapse of at least twelve benched pillars with width-to-height ratios (w/h) of 0.8 or less. This study elaborates on