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By Mike Moody

"No matter what type of ore is being extracted from a mine, mucking with front loaders can be accompanied by wet fines that cling to every surface. Once loaded into a hopper or conveyer transfer chute, viscous material can quickly build up on the walls to create bottlenecks, clogging the chute and causing expensive downtime.Clearing material from hoppers, chutes, bins and vessels can be done using manpower and tools on hand, but safety experts recommend considering a solution that prevents exposing workers to potential hazards. Operators at modern mining sites, such as the Eagle Mine, located in Western Marquette County of Michigan’s Upper Peninsula, understand that using specialized equipment reduces worker exposure, offers the safest mode of production and provides the most cost-effective lasting results.“Safety is a top priority for us,” said Ted Lakomowski, lead reliability technician at the Eagle Mine. “When we experienced clogging and downtime at the processing mill, the crew naturally swung into action to resolve it, but we immediately sought a safer long-term solution.”Stope mining for nickel and copperOwned by Lundin Mining, a globally diversified base metals mining company headquartered in Toronto, ON, Canada, the Eagle Mine is the only primary nickel mine in the United States, producing 1.5 percent of the world’s total nickel production. The first operation permitted under Michigan’s Part 632 Non-Ferrous Mineral Mining Law, it opened in 2014 and is expected to produce 163 kt (360 million lbs) of nickel, 134 kt (295 million lbs) of copper and small amounts of other metals over its estimated nine-year lifespan.The company extracts approximately 2 kt/d (2,200 stpd) from the underground nickelcopper mine using a bench-and-fill stoping process. Accessed from the surface by specialized underground trucks, the vehicles carry about 45,400-kg (100,000-lb) loads through a 1.6-km (1- mile) long and 5.4-m (18-ft) diameter ramp shaft descending into the earth at a 13 percent grade. Stoping is a bottom-up method that involves systematically blasting columns of loosened ore that is then mucked by front loaders into trucks and backfilled using cemented and uncemented rockfill."

Aug 1, 2019

"INTRODUCTION Foam, unless intentionally created, in any industrial process presents operational problems, or at a minimum, is a nuisance. Some foam problems are unique to a given industry and others are common across many industries. A few problems foam presents to any particular industry are: (a) Poor Housekeeping, (b) Environmental impact, (c) Safety Hazards, (d) Slower Production Rates and, (e) Reduced quality of the end product. Defoamers address these issues. Sadly, the assumption in most industries is all defoamers are alike. In reality, a lot of chemistry is involved in the manufacture of even the simplest defoamer sold today and rarely are any two defoamers “just alike”. Today’s defoamers can include polymer chemistry, fatty esters, alkoxylated alcohols, silicone chemistry, silicone surfactants, ethoxylated and propoxylated block polymers, and a tremendous amount of emulsion chemistry just to name a few. This paper will discuss the various types of defoamers, defoaming mechanisms, the advantages and disadvantages of defoamer selections, and how to choose the proper defoamer for your application. Before a discussion of defoamer can be brought about, foam generation and composition must be discussed. WHAT IS FOAM? Foam is a colloidal suspension of a gas dispersed in a liquid. Most often foam consists of air dispersed in water. If a stream of air is introduced into a liquid, the bubbles produced assume a spherical shape. As the density of the bubble is less than the liquid the bubble rises. When the individual bubbles reach and pass through a surfactant free liquid they collapse. Air from the bubble dissipates and the liquid previously surrounding the bubble flows back.It should be noted a pure liquid will not foam. In the case of air dispersed in water a surfactant is necessary to make the water support a stable foam. A surfactant is a term used to describe a surface active agent; a compound with a hydrophilic end and a hydrophobic end on the same molecule."

Jan 1, 2016

By G. Luttrell

Coal preparation plants play an important role in modern society by providing high quality feeds for coal-fired utilities, industrial boilers and metallurgical coke facilities. Unfortunately, field data indicate that preparation plants are often not operated under optimum conditions, resulting in lower productivity and lost profits. In many cases, this shortcoming can be attributed to a failure by plant operators (i) to recognize the importance of correctly adjusting plant operating conditions to accommodate requirements dictated by coal sales agreements within different coal markets and (ii) to properly account for variations in product moisture with particle size across different plant circuits. This paper discusses the important influence of moisture constraints on preparation plant optimization and provides a case study to illustrate the potential gains that can be realized via proper understanding of plant moisture control.

Jan 1, 2009

"The National Mining Hall of Fame and Museum (NMHFM) announced the class of 2019 National Mining Hall of Fame inductees. This year’s inductees, selected by the National Mining Hall of Fame’s Board of Governors, represent exceptional financial acumen in assembling several operations that formed the basis of a successful American mining company; conception and development of equipment which contributed to improved efficiency and mine safety; and unrelenting advocacy for the U.S. mining industry and its workers. These individuals, selected for being determined, forward-thinking innovators, doers and leaders have propelled the industry toward vastly improved safety and social responsibility.The Prazen Living Legend of Mining Award, named for renowned mining artist Gary Prazen, will also be presented at the ceremony. This award recognizes an individual or organization for significant and sustained commitment to educating the public about the relationship of mining to our everyday lives through educational materials, programming, and outreach.2019 National Mining Hall of Fame inducteesFrank Calandra, Jr. has devoted more than 50 years to the mining industry and he is an icon in ground control technology for the mining, tunneling and civil construction industries.From the ground up, his passion, sweat equity and shrewd business acumen have grown Frank Calandra, Inc. (FCI) and Jennmar from a single plant in Pennsylvania to a world-class enterprise with 25 plants employing thousands globally. As evidenced by Calandra’s more than 20 patents on ground control devices (not to mention the additional 80 patents his companies hold), his innovation and commitment to safety have made underground mining safer and more efficient. In the late 1970s and early 1980s, Calandra was instrumental in upgrading American Society for Testing and Materials (ASTM) standards in roof control for both state and federal regulations. Through his work with industry associations such as the National Mining Association, National Coal Council and Center for Energy and Economic Development, among others, Calandra has contributed his time, expertise and financial support to ensure a balanced political and regulatory climate for mining. Calandra is an inductee of the West Virginia Coal Hall of Fame."

Aug 1, 2019

Introduction Aggregate mining impacts on water resources are a source of concern to local governments. To evaluate those impacts, the Minnesota Department of Natural Resources conducted a four-year study at three gravel pits (two alluvial and one beach-ridge) and five quarries (flat-lying Paleozoic limestone). This research provides the first comprehensive look at aggregate mining impacts on ground-water systems in Minnesota. The results will be used by government officials making permitting decisions about aggregate operations and by responsible owners of aggregate mines as they plan their operations to avoid conflicts with neighbors and with resources dependent on ground water and surface water. Natural aggregate (crushed stone, sand, and gravel) is a vital part of our economic infrastructure in Minnesota. Aggregate is used for road and bridge construction and in a variety of building materials. In 2003, the value of construction sand and gravel and crushed stone in Minnesota was approximately $245,000,000. As Minnesota’s economy continues to expand, the demand for aggregate will continue to grow. Sand and gravel pits are located in every county in Minnesota. In 1990, the Minnesota Department of Natural Resources, Division of Minerals (DNR Minerals), estimated the number of active and inactive operations at 1500 with the view that this number was likely too low. Quarries for mining limestone, dolomite, sandstone, and hard rock (granite and quartzite) are found in 34 counties. A 1990 DNR Minerals inventory found 165 active operations, 88 percent of which were limestone quarries (Nelson and others, 1990). That same inventory counted 1,367 inactive operations, 70 percent of which were limestone quarries. Aggregate mining is an extractive use of resources: mining alters the landscape and its natural hydrologic system. When a new pit or quarry is proposed or when an existing operation needs to expand, local governments and citizens typically have many questions about the impacts mining might have. Local governments, which are responsible for reviewing these operations, rarely have the budgets to hire experts to evaluate potential impacts of quarry and gravel pit proposals. The Minnesota Legislature’s Aggregate Resources Task Force identified that local government units (LGUs) often lack the expertise to assess ground-water models (Southwick and others, 2000).

Jan 1, 2007

By H. Copur

Roadheaders have become widely used in underground mining and tunneling operations because they offer the flexibility to excavate soft- to medium-strength rock formations. A critical issue in successful roadheader application is the ability to develop accurate and reliable estimates of machine production capacity and the associated bit costs. Increased pressure to improve productivity and lower costs in the mining and civil construction industries has been the driving force behind the more wide- spread use of mechanical excavation systems. This has caused both industries to move away from the conventional drill and blast methods. Additional benefits of mechanical mining include improved safety, reduced ground support requirements and fewer personnel. These advantages, coupled with recent enhancements in machine performance and reliability, have resulted in mechanical miners taking a larger share of the rock excavation market. Roadheaders are the most widely used underground partial-face excavation machines for soft- to medium- strength rocks, particularly for sedimentary rocks. They are used for development and production in soft rock mining (main haulage drifts, roadways and crosscuts), particularly in coal, industrial minerals and evaporitic rocks. In civil construction, roadheaders are used to excavate railways, roadways, and sewer and diversion tunnels in soft ground conditions. They are also used to enlarge and rehabilitate underground structures. Their ability to excavate almost any profile opening also makes them attractive to those mining and civil construction projects where various opening sizes and profiles are needed. In addition to their high mobility and versatility roadheaders are generally low capital cost systems com- pared with most other mechanical excavators. Because of higher cutting-power density due to a smaller cutting drum, roadheaders can excavate rocks harder and more abrasive than continuous miners and borers.

Jan 1, 1998

By Harvey P. Knudsen

Case studies are presented in this paper to illustrate the usefulness and applicability of using conditional simulation in under- ground coal mine planning. Conditional simulation is a technique developed in the last five years that allows the building of a simulated ore body (or coal deposit) model. Construction and validation of the simulated model is described in order to show how well the model reproduces the essential characteristics of the deposit. In the model, the thickness, ash, and sulfur content are known everywhere in the deposit and each variable has the same mean, variance, and spatial variability (variogram) as that variable has in the real deposit. Use of the simulated deposit in the design of drilling strategy for long range mine planning is demonstrated in me case study. Determining the potential of short term production scheduling to reduce the fluctuations of sulfur in run of mine coal is described in the second case study.

Jan 1, 1980

By Daniel W. Kappes

Testing ores for heap leach operations traditionally follows a progression of bottle roll tests, bucket and column leach tests, and very expensive large field leach tests. Enough data is now available to streamline the procedures. Data from five different operations shows that recoveries from large field leach tests can be predicted from the bucket tests. Initial recovery times in large field leaches are longer than in bucket tests- a typical response is eight days versus twenty days to the same recovery percentage; but the ultimate percent recoveries (after 60 days) are normally very close. Methods of mining and stacking can radically affect recoveries from clay-rich ores. Leaching of uncrushed ores provides special testing problems, since accurate samples smaller than several tons cannot be taken.

Jan 1, 1981

By Don Phelps, John Hawley, David P. Field

In recent years observational techniques of tunneling have become increasingly popular methods to facilitate complex underground infrastructure projects. The traditional design and construction management practices developed in Europe have been adapted for application in North America to suit a more restrictive management and legal culture. This paper will discuss three recent projects, the San Diego Mission Valley East Extension, Washington Dulles International Airport People Mover, and the Seattle Beacon Hill Station and Tunnels, with the objective of identifying the challenges of applying observational tunneling methods to established contractual practices in North America.

Jan 1, 2005

By Jacek B. Stypulkowski

This paper discusses the challenges faced by the design team of the under-river crossings of electric transmission feeders in New York City, a densely populated urban area. The under-river crossing of a 345 kV feeder was initially designed as Horizontal Directional Drilling (HDD), but was redesigned as a utility tunnel because of site con¬straints on both sides of the river. Multiple studies addressed location, available tech-nologies and costs. Multiple soil investigation phases addressed design aspects of HDD, as well as tunneling. Contractual issues varied from a design build alternative with Geotechnical Data Report (GDR) to design tender approach with GDR & Geotechnical Baseline Report (GBR).

By Fred Breu, Ronald E. Heuer

INTRODUCTION The Point Lepreau nuclear generating station was constructed in the late 1970's and early 1980's by the New Brunswick Electric Power Commission. Point Lepreau is a small peninsula on the north shore of the Bay of Fundy, about 55 km west of St. John, New Brunswick. Cooling water for the plant was to be obtained from and discharged into the Bay of Fundy by the system of shafts and tunnels illustrated in Fig. 1. The design engineer for the cooling water system was Albery, Pullerits, Dickson and Associates, Ltd., Toronto. Ferrera-Resco Ltd, Windsor, Ontario, was contractor for construction of the cooling water shaft and tunnel system, which was done between 1976 and 1979. The senior author was project manager for Ferrera-Resco, the junior author served as consultant to Ferrera-Resco on evaluation of certain geotechnical questions which arose during construction. SITE CONDITIONS Geology Except for limited overburden soils at the onshore shaft sites, the tunnels and shafts were constructed entirely in Triassic conglomerate, sandstone, and siltstone, with some shale interbeds. The bedding strike averaged about N6°E, The dip was to the west at about 30° along the Discharge Tunnel and 40° along the Intake Tunnel. Rock along the Intake Tunnel was mostly sandstone and siltstone and more thinly bedded, with RQ D generally in the range of 50 to 60%. Rock along the Discharge Tunnel tended to be coarser sandstone and conglomerate and more thickly bedded, with higher RQ D averaging about 80%. In addition to bedding joints, two other joint systems were identified

Jan 1, 1985

By M. Fan, Z. Long

"This paper presents some studies on recovering valuable elements from Chinese coal by-products, including coal combustion fly ash, stone coal ash, and coal flotation tailings. Both commercialized technologies and economic potential recovery methods are described in this study. Magnetically stabilized air-dense medium fluidized bed separation, tribo-electrostatic separation, froth flotation, and hydrometallurgical methods are discussed in recovering various valuable elements in Chinese coal by-products from different coalfields. These valuable elements include iron, carbon, aluminum, rare earth elements, lithium, gallium, germanium, uranium, titanium, scandium, silicon, vanadium and phosphorus, etc. The ultimate goal is to fully utilize all valuable elements in coal by-product. Each component within coal by-product should be efficiently segregated to its highest value. INTRODUCTION Coal is mainly composed of energy-producing elements carbon and hydrogen. In addition to these elements, coal usually contains many other valuable elements, including iron, aluminum, silicon, rare earth elements, lithium, gallium, germanium, vanadium, uranium, titanium, scandium, and phosphorus, etc. These coal-associated elements are significantly enriched in coal combustion by-product fly ash because of majority of main components, carbon and hydrogen elements, being removed. Table 1 provides the chemical composition range of the main elements oxides in 12 Chinese fly ash samples collected from coal power plants located in Northeast China, Northwest China, Southwest China, and Southeast China. It can be seen from Table 1 that the major mineral components of different ashes are similar, but the bulk chemistry of different fly ashes may vary widely due to the changes of ratios of the mineral components in different coals. The major mineral components in various Chinese coal combustion fly ash are silicates, iron oxides, and unburned carbon."

Jan 1, 2017

By E. Allen Wendt

It is both a great pleasure and something of a challenge for me to have this opportunity to address a gathering encompassing such a wealth of expertise in the minerals field, It is particularly challenging because I have been asked to turn your attention from the relatively glamorous subjects of gold and money to the more mundane questions of our International commodity policy and the place of buffer stocks in that policy. However, these questions may be of more immediate importance for our economic interests at home and Abroad. I can testify that the problems affecting international commodity markets and the possibility of international action To resolve those problems are matters of real concern to Washington as well as to your industries,

Jan 1, 1978

By L. B. Hales

Expert control of grinding and flotation plants has been successfully used in the minerals industry since the 1970?s. The earliest of these systems were written in a hard-coded fashion in FORTRAN, BASIC or Pascal. Second generation systems were built using the first experimental expert system shells that were being developed in the artificial intelligence community. Later systems were deployed in expert system shells designed for real-time processing plants that also included the ability to model the process with neural network models and optimize setpoint selection through the use of genetic algorithms. Significant performance increases have been achieved using these systems, but in general, they suffer from the static nature of their rules and to a degree the process models also. Typical improvements quoted in the literature suggest throughput rate increases of 4 to 8 percent and recovery increases of 1 to 4 percentage points. In over 30 years of designing and installing expert systems we have never seen performance numbers less that these but have often seen numbers in excess of the high values. However, once the system has been installed and tuned up the performance usually does not improve much thereafter. Granted, the initial increases in throughput rate and recovery are significant but a question always lingers, that is, can the expert strategies be modified further to squeeze a little more improvement out of the system. The answer to this question is a resounding yes, however a complete understanding of what we do well as designers and operators of expert control systems is required as well as how we can improve upon our best practices is required to move us from the performance plateau we have been on for a number of years to a new higher level of performance.

Jan 1, 2009

By Russell Frith

The entire subject area of micro-seismic events due to stored strain energy, as distinct from gas-driven coal outbursts, can be readily sub-divided into firstly events with their energy source from within the coal seam (termed “bursts”) and secondly, event with their energy source outside of the coal seam in either the overburden and/or floor strata. The reason for sub-dividing micro-seismic events in this manner is that if the causation mechanisms and associated geotechnical conditions are materially different, then effective pre-mining predictions and subsequent operational controls may also differ. Attempting to explain a multitude of micro-seismic event types without consideration of varying source mechanisms will inevitably lead to inadequate causal explanations and effective controls.

By R. E. Chaves

San Martin Mine is an open pit, gold heap leach operation located approximately 70 kilometers from the Honduran capital of Tegucigalpa. Mining operations commenced in 2000 and were completed late in 2007, while heap leaching operations continue. Reclamation was executed concurrently with operations to the extent practical. The area has distinct rainy and dry seasons and closure objectives include: prevention and mitigation of acid rock drainage, sediment and erosion control, and mitigation of visual impacts. Final closure is well underway at San Martin and this paper describes the closure processes conducted to date, problems encountered, and the subsequent lessons learned.

Jan 1, 2009

By Yunxing Cao, Xinsheng Zhang, Bingbing Meng, Shuaifang Guo, Li Wang, Junsheng Zhang

During the initial process of mining a longwall working face, it is often found that the roof will not collapse readily, which increases the risk of later roof collapse disasters. Explosive and hydraulic fracturing are common roof weakening techniques; however, they have certain limitations. In the present study, CO2 fracturing was used for roof weakening during the initial mining phase in the Changcun coal mine, China, which is a novel strategy. First, by analyzing the lithological characteristics of the working face and applying combined beam theory, the breaking spans of the top coal, immediate roof, and main roof were determined before weakening. An F-35 CO2 fracturing device with a rated pressure of 270 MPa was used, which provides fracturing energy equivalent to 0.968 kg of TNT. The fracture radius of the main roof was studied by ANSYS/ LS-DYNA combined with the hanging roof-breaking theory to determine the optimal layout of CO2 fracturing drills. The results show that the breaking spans of the top coal, immediate roof, and main roof were reduced by 3.99 m, 7.66 m, and 22.03 m, respectively. The main roof collapsed as the working face advanced, eliminating the chance of later roof collapse disasters. Compared with hydraulic fracturing and explosives, CO2 fracturing is safer and more practical, giving it significant application potential.

Nov 23, 2023

By David E. Nicholas, Steven R. Dismuke, Paul F. Cicchini

The Buick mine, located 195 kilometers (120 miles) southwest of St. Louis in the Viburnum Trend, is owned and operated by Homestake Mining Company. The mine produces lead and zinc ore from a room and pillar mining method at a depth of approximately 335 m (1 100 ft). The Buick orebody typically averages 60 to 120 m (200 to 400 ft) in width with ore thicknesses ranging from 2.4 to 36.6 m (8 to 120 ft). The mine is divided in two; the halves are referred to as the North mine and South mine orebodies. The North mine orebody contains the higher grade ore; however, the developed reserves for the South mine orebody comprise about 60 percent of the total developed reserves for the Buick property. Existing pillars represent one-third of the total developed reserves.

Jan 1, 1986

By I. J. Duckworth

During the last twenty years computers have be-come widely used to assist with the simulation and design of large scale, primary ventilation systems. However, to date there are few computer programs available to help with the modeling of auxiliary ventilation in dead-end headings or tunnels. This paper presents the results of the first year of a research and programming study dedicated to the development of a user-friendly duct simulation tool. Included is a literature review that summarises publications on duct leakage and resistance, on previous programs developed for the simulation of airflow in ducts, and case studies on extended ductlines in mines and tunnels. The methodology behind the development of Ductsim, a Windows based simulation program is presented.

Jan 1, 2000

Fossil resin types occurring in the Hiawatha seam of the Wasatch Plateau coal field, Utah, have been separated according to color and their physical and chemical properties evaluated. These resin types were separated into four color fractions, yellow, amber, light brown, and dark brown. Each resin type has then been subjected to comprehensive spectroscopic examination and other physical methods of characterization. Included among the spectroscopic methods of characterization are FTIR and 13C NMR spectroscopy. Physical properties that have been measured include density, optical, and magnetic properties. These analyses reveal that the resins are distinct from other macerals, predominantly nonaromatic in nature with small amounts of oxygen functionalities and a low degree of unsaturation. The four resin types show distinct differences in certain physical and chemical properties such as density, hexane solubility, magnetic susceptibility, and aromaticity.

Jan 1, 1990