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By Edward J. Budill

One of the most dramatic innovations in the materials handling industry has been the development of stacker cranes and automated material handling systems. The stacker crane with its many capabilities and the development of reliable industrial automation controls have combined to produce dramatic achievements in an area once characterized by inefficiency lack of management attention, and capital investment. In many areas of application however, stacker cranes and high rise storage systems have been designed and installed with insufficient thought given to their integration into the overall operations of the plant or distribution facility. This paper will look at some new and interesting breakthroughs in the integration of stacker cranes and high rise storage systems into the total manufacturing plant system. In this paper we will refer to both bridge type stacker cranes and aisle stackers. The bridge type stacker crane was developed first and was initially developed with forks or other handling devices hoisted up and down a rigid or telescopic mast. This mast system was suspended from a trolley mounted on an overhead crane bridge. Today, the primary application of the bridge type stacker is in warehousing systems for handling basic metal products such as coils, bars, sheets and plates. There is no question that the bridge type stacker has achieved notable results in storage and handling of these commodities. However, a new area for stacker crane application has been developing which in many cases over-shadows the accomplishments in the storage area. This is the application of the bridge stacker as an integral part of the manufacturing processes, or in other terms the production applications of stacker cranes. The stacker crane has a number of attributes which makes these applications very important. First, the crane bridge provides the stable platform for the mounting of machinery which can accommodate the hoisting and lateral movement of large capacity loads. Today stacker cranes are being built with capacities of up to 30 - 40 tons. The bridge cranes can easily accomplish accommodation Of these large tonnages. Secondly, the mast system provides a stable platform for the mounting of a wide variety of manipulating devices which can be used for the placement of material into manufacturing processes, the extraction of this material from these processes, and movement to other points in the process area. These attributes combined with excellent operator control and safety have led to development of the stacker crane as a production tool.

Jan 1, 1973

The Cadia Mine is located 25kms South West of Orange in the central west of New South Wales (NSW), Australia (Figure 1). Orange is a major regional centre with a population of 35,000 people. Cadia has a history of mining and exploration dating back to 1851 and shortly after the first Australian gold rush at Ophir, north of Orange. Newcrest Mining commenced an exploration program at Cadia Hill in 1992. This identified a substantial zone of copper and gold mineralization. Subsequent resource definition drilling defined an orebody with a mineable reserve of 200 million tonnes of ore with an average gold grade of 0.74g/t and 0.17\ copper. A full feasibility study commenced in 1994, approvals to proceed with development were granted in September 1996 and the processing plant was commissioned in July 1998. The project came in on budget at A$440 million and on time, 24 months from design to construction. The estimated operating cost at the time of commissioning was A$8.85/t of mill feed.

Jan 1, 1999

By B. Andersen, P. Somasundaran

An accurate knowledge of the interactions among mineral particles and between such particles and dissolved and precipitated species is important in developing efficient separation processes. In this investigation, interactions relevant to dispersion and selective reagent adsorption (the two main prerequisites for selective flocculation) within Florida phosphatic clay Waste were studied. Initial studies with artificial slimes, consisting of pure clay and phosphate minerals, showed dispersion of artificial slimes to be relatively easy. The problems that were encountered during selective flocculation of the artificial slimes were due to unselective polyacrylic acid adsorption on clay, which was caused by the presence of multivalent calcium ions on the exchangeable cation positions on the clay surfaces. This problem could be solved by exchanging calcium for sodium, which reduces the interaction between the polymer and the clay surface. This procedure, however, was not successful for mineral mixtures. Natural slimes were found to be much more difficult to disperse. This was attributed to the presence of cementing materials such as humic substances and Al and Fe (hydr)oxide precipitates. Selective removal of these cementing materials resulted in good dispersion and partial separation. A further increase in the separation of natural slimes is most likely determined by the presence of calcium on the clay surfaces, as was found for the artificial mixtures.

Jan 1, 1994

By J. A. Finch, B. J. Huls

Accurate level detection is required to make full use of level in optimizing control strategies for flotation columns. Techniques based on pressure and electrical conductivity are compared. Pressure and conductivity profiles give good agreement on level. Level calculated from single and multiple pressure values became more accurate using, in order, one, two and three sensor locations. The level estimate remained in error, however, because, unlike the collection zone, froth zone bulk density varies with height. A conductivity probe continually updating the conductance profile is a practical method of obtaining an accurate level.

Jan 1, 1990

By Michael L. Maniocha

Most magnesia (MgO), whether of natural or synthetic origin, is used in the dead-burned or periclase form as refractory linings for the production of steel. Continued research in refractory science, combined with good refractory maintenance and improvements in steel-making processes, have resulted in decreased use of magnesia. To make up for this loss of business, producers of synthetic magnesia have started to manufacture a variety of magnesium-based chemicals that are used in many industries. There are three primary methods of producing MgO. The first involves the calcination of naturally occurring minerals species. Most of the magnesia produced by this method uses the rhombohedra1 carbonate mineral magnesite, MgCO,. To a lesser extent, the mineral brucite, Mg(OH), is calcined to magnesia. Magnesia produced by the calcination of minerals is called natural magnesia. The second production method uses magnesium-rich brines, or sea water reacting with lime or calcined dolomite to produce magnesium hydroxide. The magnesium hydroxide is subsequently calcined to magnesia. Material produced in this way is called synthetic magnesia. The third major method of production uses saline lake brines to produce magnesium chloride. Magnesium chloride brine is sprayed into a reactor where it thermally decomposes into MgO and HCl. The magnesia is purified by slaking to magnesium hydroxide followed by calcination. Magnesia produced in this manner is also know as synthetic magnesia (Duncan and McKracken, 1994). The degree to which the magnesium minerals or the synthetically prepared magnesium hydroxide is calcined governs the physical properties of the resulting MgO. It is the physical properties that dictate the end use for the product. The terms used to describe magnesia vary along with the degree of calcination. Table 1 summarizes the terminology used when discussing the various forms of magnesium oxide.

Jan 1, 1997

By P. James

"INTRODUCTION Control of target stream acidity is widely used in MIW (mining influenced water). Tailoring pH (a measure of acidity) finds application for controlling key chemistry in both process and waste streams. Traditional lime addition for neutralization and precipitation is most often used but has high reagent costs and results in large amounts of mixed metal sludge requiring costly disposal. A new adaptation of BPS’s patented DEMET™ technology (Dynamic Electrolytic Metal Effluent Treatment) platform offers a potentially improved and “reagentless” alternative to traditional chemical addition for pH adjustment. Electricity rather than chemical addition utilized in BPS’s proprietary approach controllably tailors target stream pH. The method offers a simple, low-cost processing technique yielding cleaner treatment chemistry. BPS’s “green” approach may yield lower operating (OPEX) and life cycle costs and significant reductions (up to 50%) in sludge generation compared to conventional lime treatment. It can also allow new opportunities to generate revenue via selective recovery of valuable processing byproducts. Specific savings and revenues depend on the target site chemistries, details, and processing goals. A more detailed discussion of the process and its operational principles may be found in Reference One.[1] Here application of the BPS treatment to POx (Pressure Oxidation) leaching as an alternative to traditional chemical addition is examined. An example operation process flow for gold mining is considered.[2] Promising processing points for potentially replacing conventional processes with DEMET are noted. The possibilities for lowering OPEX costs, lessening sludge creation, and capturing various valuable byproducts and residuals are examined. Financial life cycle benefit estimates of the principal gains provided by DEMET application to the example operation are noted. Extension and generalization of the analyses to a wider range of scenarios is explored."

Jan 1, 2016

By R. Raymond

The occurrence and distribution of organic sulfur in coals may be investigated using electron probe microanalysis, scanning electron microscopy, and optical petrography. A general relationship exists between macerals and organic sulfur contents in individual coals: sporinite, resinite = micrinite, vitrinite > pseudovitrinite = semifusinite = macrinite > fusinite. With increasing organic sulfur content of a coal, the total range in organic sulfur content between macerals containing high and low organic sulfur contents likewise increases. Furthermore, the organic sulfur content of the vitrinite in most coals equals the organic sulfur content of the coal. For any individual coal, organic sulfur contents of macerals correlate inversely with reflectance-in-oil measurements, but the amount the organic sulfur contents vary between macerals cannot be calculated based solely on the coal's rank. Formation of pyrite following peatification has no effect on organic sulfur contents of surrounding macerals.

Jan 1, 1986

By D. Park, V. Gall

The three-dimensional finite element technique combined with a progressive failure approach were used to simulate stress distributions in a complete mine section that occur in response to a longwall mining operation. Due to the availability of a Cray supercomputer, a large-scale, three-dimensional, finite-element model was developed for the analysis. The Hoek-Brown failure criterion, which describes a realistic behavior of rock masses, was used for the simulation of progressive failure. A comparison of calculated and monitored stresses in the mine has shown that the model gives a good representation of stresses in the mine structure.

Jan 1, 1992

By M. Brnich, S. Kramer, B. McNamara, T. Hethmon, M. Pedersen-Howard, S. Rajapaske, D. Lingenfelder, B. Huber, D. Hebig

"The development of mining safety and health management as a recognized profession has been long in coming. Over the last 150 years, the mining industry has evolved from having individuals randomly involved in safety related work with no specific responsibilities or qualifications, on to the designation of individuals responsible for safety, regardless of knowledge, qualifications and experience and finally to today’s expectation that virtually every mine and mining company has designated individuals operating as safety and health professionals. Further, with the complexity, risk potential and moral expectations surrounding safety, people who address mine safety and health management are justifiably expected to function in a professional capacity including:1. Rendering a specialized service based on advanced knowledge and skill.2. Maintaining a high degree of obligation to those most affected by mine safety outcomes.3. Bound by an ethical code in working with the public, employers and miners.4. Maintaining confidentiality with an employer or client. This historical change parallels thedevelopment of other professions, e.g., attorneys, engineers, physicians, etc., with the exception that those professions require a license granted by a governmental agency, which is justified on the basis of public protection, in order to practice. Likewise, decisions made by today’s mine safety and health professionals, both directly and in association with other managers, clearly have a significant impact on the life and welfare of miners throughout the world.CertificationIn light of this, there is growing need to improve standards of competency and professionalism for those who work in mine safety and health management. An effective mechanism to accomplish this, other than licensure, is the use of accredited professional certification programs. There are many professional certification programs for safety and health throughout the world (Hale & Harvey, 2012). However, there is only one certification specific to mining —the Certified Mine Safety Professional (CMSP). The International Academy of Mine Safety and Health (ISMSH-SME) was formed with the purpose of developing and managing mining safety and health certification programs for the Society for Mining, Metallurgy and Exploration (SME). In 2016, following the discontinuation of the International Society of Mine Safety Professionals (ISMSP), which developed the Certified Mine Safety Professional (CMSP) credential in the 1990s, the IAMSH-SME began the process of updating and relaunching the CMSP program. Among other work required to gain third-party accreditation both domestically and internationally, the IAMSH-SME has developed a new Body of Knowledge associated with mine safety and health management (Table 1)."

Jan 6, 2018

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

By Michael Murphy, Gamal Rashed, Brent Slaker

Many underground stone mines in the United States operate on multiple mining levels. The effects of interburden thickness, pillar offset between mining levels at various depths of cover, and in situ stress conditions are poorly understood. Pillar offset is the degree to which pillars are not columnized or stacked. In this study, calibrated numerical models are used to examine limestone pillar stability in these conditions. Also, the critical interburden thickness required to minimize the interaction between mining levels is explored. The model results show that there is interaction between numerous factors that control the stability of stone pillars in multiple-level conditions. The highest degree of local pillar instability occurs when pillar overlap ranges between 10 and 70 percent. The highest degree of stability occurs when pillars are stacked.

Jan 1, 2023

By R. K. Sinha, B. S. Choudhary, Desh Deepak, A. K. Mishra, Hemant Agrawal, Shankar Kumar

Despite several methods (empirical, statistical and machine-learning tools) to calculate blast-induced ground vibration, it is not easy to predict and simulate blast vibration precisely under varying blasting loads and strata conditions due to complications in the blasting procedure. In this study, field blast data were simulated in Ansys software using explicit dynamics, and ground vibrations for 20 single-hole blasts were monitored. The densities of emulsion explosives were in the range of 0.9 to 1.15 g/cm3. In the laboratory, rock properties were determined from rock samples collected from the mine site before blasting. The in-hole velocity of detonation (VoD) and density of the emulsion explosive were also determined and used in numerical analysis to know the ground vibrations at specific points. The results of ground vibrations predicted by the model were validated using field data.

By Landy A. Stinnett

Coal mines in the United States are the most productive in the world in terms of efficient labor employment. This is because of an abundance of workable coal beds, large infusions of capital, improved management practices and continuing competitive pressures. The standard unit of measurement for labor productivity is expressed as tons/manshift, although for underground mines, operators often refer to tons per machineshift. Articles written concerning labor productivity generally focus on measurement techniques, safety considerations, application of technology and training. This article will illustrate by example the impact of labor efficiency (or inefficiency) on the ultimate selling price of coal, f.o.b. mine site. During the past several years, the coal industry has seen significant improvement in labor use. Figure 1 shows the trends in productivity for all active mines in the United States from 1985 through 1994. Productivity in 1985 was 20.1 t/manshift (22.1 st/ manshift). This factor has increased almost linearly throughout that period to 37.5 t/manshift (41.2 st/manshift). This is a 7.2% annual compound growth rate.

Jan 1, 1995

By John Dodd

Corrosion studies in laboratory ball mills and grinding environment simulations produce corrosion rates and total metal removal rates much lower than those recorded in operating production ball mills. The corrosion component of ball metal loss in commercial mills represents less than 10% of the total loss expressed as micrometers/hour of exposure in recent USBM tests. Such small absolute losses are consistent with ball metal loss measured in production ball mill marked ball wear tests to determine effects of corrosion and abrasion resisting properties of alloys in operating mills which indicate that metal hardness and microstructure determine relative metal loss rates of a given situation. The combination of ore characteristics and grinding process dynamics determine metal loss severity. Alloying for corrosion resistance and modification of the milling corrosion environment yield relatively small metal loss reductions. Alloying and heat treatment to produce high hardness and microstructures of high carbon martensite and for cast irons, M7C3 carbides produces the lowest metal losses in typical wet grinding applications.

Jan 1, 1984

By Stanley J. Gasior

Most bituminous coal mined near Eastern industrial areas requiring high Btu pipeline gas is caking and therefore unsuitable for fixed-bed pressure gasification by present techniques. If the caking property of such coal can be destroyed the resulting fuel can be gasified in a fixed bed at pressure with steam and oxygen as a preliminary step in making a high-Btu gas. To find a practical way to convert strongly caking coals of granular or small lump size to noncaking fuel was the object of this study. In previous work strongly caking coals of 1/8- to 1-1/2-inch size was converted to a noncaking coal char by treatment in a static bed in about 3 hours [1/]and coal of 18-100 Tyler mesh in a fluidized bed in about 5 minutes.[2/] An inert gas such as `steam, nitrogen, carbon dioxide, or a mixture of all three with a small amount of oxygen was used in both studies. In our work a strongly caking bituminous coal from the Pittsburgh seam of 4-8 Tyler mesh size was converted to a-noncaking form in free-fall in about 2 seconds by dropping it through a countercurrent flow of steam containing 4 to 7 percent oxygen at 1,150°-1,200° F and 300 psig. This method should also be applicable to smaller-sized material.

Jan 1, 1965

By David E. Nicholas

Design of underground openings is becoming more critical as the mine deposits become lower in grade, initial investments increase, ore depth increases, additional safety regulations come into law, and increased ore recovery is required for conservation of minerals. Stability of these openings is dependent on the strength of the rock mass and the pre-mine stress field. The rock mass is composed of solid blocks of rock (rock sub- stance) and structural features (faults, joints, bedding, etc.). Methods of testing the rock mass strength are improving and be- coming more common, however it is difficult to justify the high cost of large scale testing for an initial mine design. An alternative to testing the rock mass is to measure the rock substance and the structural features separately, and then combine them to estimate the rock mass strength. The rock mass strength will vary depending on the orientation of the opening with respect to the structural features. The other factor affecting the stability of underground open- ings is the pre-mine stress field. Methods are available to measure "directly" the pre-mine stress in competent and relatively massive rock. These methods are costly to employ, therefore, they may not be justified in an initial study. The pre-mine stress field can be estimated based on the structural relationships formed from past tectonic events.

Jan 1, 1976

By Howard L. Hartman

The federal government's declining role in funding research has created a critical dollar gap for university departments of mining engineering. Industry is not unaffected by the drought: not only is research lagging, but hard- pressed universities are going to the private sector for funding. This paper's thesis is not that mining companies should shower universities with philanthropy, but that a quid pro quo ought to be exacted: a research partnership should be contracted on a pay-as-you-go basis. A model exists at The University of Alabama (albeit not in mining) that may lend itself to adoption by our industry.

Jan 1, 1984

By Xiaozhen Song, Ashish Ranjan Kumar, Shimin Liu

Diesel particulate matter (DPM) presents considerable occupational health hazards in large-opening underground mines (LOUM). Previous studies have primarily focused on single-factor ventilation optimization, while this study innovatively integrates booster fan configurations and loading truck placements utilizing a coupled CFD turbulence– particle tracing model. Three distinct ventilation scenarios were simulated to evaluate their effects on DPM dispersion and dilution efficiency. Results indicate that dual booster fans substantially enhance airflow distribution, increasing air exchange efficiency; The migration pathways of DPM closely align with airflow trajectories, and air turbulence is the predominant factor influencing particle behavior within LOUM; Loading truck placement critically influences local DPM accumulation; Airflow effectiveness diminishes markedly with distance from booster fans, causing stagnation at distant working faces. The coupled CFD approach accurately captured airflow–particle interactions, offering valuable insights for optimizing mine ventilation strategies and effectively mitigating miners’ exposure to DPM.

Feb 22, 2026

By Jozef S. Stachulak

INTRODUCTION Conveyor belt fires represent a serious hazard in underground mines. This fact is well understood in most mining countries. The statistical data for Ontario mines (1) indicates that the majority of the conveyor fires occurred at the head pulley of the conveyor belt. The main emphasis for fire prevention and detection should then be concentrated at the drive pulley of the conveyor designed to transport non-combustible material. In the case of conveyor belt fires, it is of utmost importance to detect the hazard at an early stage, when the overheating has not yet reached the ignition point. Thermal noise detection sensors were installed in 1987 at several conveyor sites at Inco mines. PRODUCTS OF COMBUSTION THERMAL DEGRADATION OF CONVEYOR BELT Various investigations on conveyor belt fire hazards have been made in the past (2, 3, 4, 5, 6, 7). Several belt samples (6, 7) were subjected to thermal oxidative degradation. The belts used in these tests were neoprene, polyvinyl chloride and styrene-butadiene rubber (6). About 70 different compounds were identified in the volatile thermooxidative products. As expected, hydrogen chloride was the major toxic product formed, accompanied by relatively low quantities of other toxic compounds such as carbon dioxide, carbon monoxide, sulfur dioxide, carbon disulfide, hydrogen sulfide, benzene, chloroprene, cresols, chloroethanol, formic acid and C8 hydrocarbons. The research investigation (8) performed by the USBM indicated that "smoldering combustibles generate a very low level of CO compared to the level of smoke produced". The cited publication (8), states that, "During smoldering combustion, typical mine combustibles produce about 2.5 times more smoke than CO. As fires develop to their flaming stages, the trend reverses and about eight times as much CO is produced as smoke." The reader is referred to several significant sources of additional information pertaining to emission products that can be found in references (8), (9), and (10). ANALYSIS OF FIRE HAZARDS U.S.A. AND ENGLAND Nearly 15 percent of all underground coal mine fires in the United States involved ignition of conveyor belts (7). In many cases, the fires propagated through thousands of feet of belt entry and created losses in the millions of dollars. Some of these fires consisted of rubber belts. Some involved polyvinyl chloride and neoprene belts that were classified "fire resistant". Typically, a belt fire begins after the conveyor is stopped. The fire is initiated by burning coal dust and grease accumulation around defective rollers or belt drives that have become heated by friction (7). An analysis of 113 conveyor fires (11) showed that 41 originated at the driving pulleys, 32 at the defective rollers, and 40 elsewhere on the conveyor system. The severity of the fire, which can spread along a conveyor road, has been emphasized by the disaster at Creswell Colliery, Derbyshire, on September 26, 1950, when 80 men were overcome and killed by toxic fumes from the fire (12). The fire started from smoldering caused by friction, and developed into a flaming combustion, propagating along the roadway containing the rubber belt at an estimated speed of 40.2 m/s (90 mph), and travelling a total of 650 m (2100 ft) THE INFLAMMATION OF CONVEYOR BELTS THE MECHANISM OF IGNITION Defective operation of a conveyor belt may start a fire in several ways: - Friction of the belt on the drive pulley. - Jamming of a guide roller, and others.

Jan 1, 1991

By Daniel F. Meyer, William C. Paschen

INTRODUCTION The problems involved with moving millions of tons of rock are being addressed by nationally recognized tunnel contractors who have converged in Chicago over the past 5 years. This wealth of expertise has been needed to meet the risk and challenge of constructing the world's largest network of underground tunnels which in turn has required a dramatic advance in the art and science of tunneling. These pioneers, through innovation, adaptation, and hard work, have eliminated the one major concern of The Metropolitan Sanitary District of Greater Chicago - how to move 8 million tons of rock. The Metropolitan Sanitary District of Greater Chicago (MSDGC) serves 122 municipalities covering 866 square miles in Cook County, Illinois. Of these cities, towns, and villages, 53 have combined sewer systems. On an average of once every four days, these systems overflow about 4 million gallons of combined sewage and rainwater into the area's rivers and canals. The overflows occur at approximately 640 outfall locations of which 10% are owned by the MSDGC, with the remainder of the points belonging to various other municipal bodies. All those who own these "point" sources of pollution are in violation of Illinois State and Federal regulations. To enable its member municipalities to come into compliance with State and Federal law, the MSDGC is implementing its Tunnel And Reservoir Plan (TARP). TARP is a regional solution to the problem of combined sewer overflow in the metropolitan Chicago area. TARP will greatly reduce the pollution of area waterways by intercepting the combined sewage and rainwater carried in the existing sys-

Jan 1, 1981