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By Michael L. Nave

Mining belt conveyor elements are becoming larger and more expensive. Conveyor reliability requirements are rising. Conveyor condition monitoring can aid maintenance, reliability, and risk management in conveyor system operation. This paper examines the application of condition monitoring in coal mining belt conveyor systems. Types and form factors of condition sensors are described. Example costs are included. Suggestions for OEM developments are examined. Application problems are discussed. Two simple cost case studies are presented.

Jan 1, 2000

By Thomas R. Hightower

The Thunderbird plant was erected in Sullivan County in Indiana during 1958-1959. It was first put in operation in March of 1959. At the present time the source of the raw coal is from the Indiana No. 6 seam. The underground operation at present consists of two continuous mining units and two conventional units. The underground is all belt haulage and the first unit with which this paper is concerned is the slope belt. It is a 48-inch-wide inclined belt with 980-foot centers and a lift of 275 feet. The belt is powered with a 350 H, P, motor and has a rated capacity of 600 Tons per Hour. The belt is equipped with a Merrick Scale Company Weightometer, The raw coal moves from the belt to a 6'x12' extra heavy Allis-Chalmers Ripl-Flo equipped with 6" round-hole screens. The over product of the screen is fed into a 10'x20' long McNally- Pittsburg rotary breaker equipped with 4-l/2" round-hole screens. The oversize rock is discharged into a bin that is emptied with a refuse truck. The through-product of the breaker, along with the through-product of the Ripl-Flo, passes either directly to the McNally Giant washbox or to a 36" belt that transports it to a 1000-ton storage bin,' The change from either to the washbox or to the storage bin is made by use of a motorized gate controlled by the plant operator,

Jan 1, 1961

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 Joshua Cole, Joshua Sovechles, Christian Cardoso, Guillermo Bermudez, Martta Hirsi, Joshua Dettamanti, Rabia Abbasi

The implementation of technological advancements in flotation is key to optimize performance in mining operations. Consequently, flotation cell’s performance is highly dependent on the effectiveness of the mixing mechanism. A more efficient flotation mixing mechanism is likely to improve metallurgical performance and optimize energy consumption, which is the motivation for Metso’s journey to develop the latest iteration of FloatForce®. Looking to test the new design at plant scale, Metso approached the Kennecott Copperton concentrator, which is continuously looking for different venues to improve metallurgical performance. In this context, a test campaign was conducted to implement this new flotation mixing mechanism in their rougher circuit during 2024. The industrial trial consisted of several sampling campaigns assessing different operational parameters for comparison purposes around a 300m3 flotation cell. The effect of the new flotation mixing mechanism on the cell’s power draw was also studied. The results of this trial at Kennecott are presented in this paper. Overall new flotation mixing mechanism, FloatForce+ was seen to perform as well as the original FloatForce.

Feb 1, 2025

By Kadri Dağdelen, Matthew Deutsch, Thys Johnson

Nested pit analysis in open-pit long range mine planning is used to define approximate ultimate pit limits and an initial high-level schedule in the early stages of a project. Modern ultimate pit optimizers can solve for dozens, or even hundreds, of nested pits however often a smaller subset of pits which are evenly spaced with respect to contained tonnage are desired for downstream analysis. In situations where that pushback selection process must be automated, such as when performing sensitivity analysis, or when the best subset of pushbacks is required; an optimization procedure is warranted. This paper describes a dynamic programming algorithm for selecting pushbacks following nested pit analysis, which is performant and addresses a long-standing inconvenience faced by long range open-pit mine planners.

Jun 25, 2023

By John F. Clarkson

White Pine Copper Company built and operated, from August, 1962 through May, 1963, a pilot plant to recover copper using a cyanide percolation leach of the sand fraction (+400 mesh) of the mill tailings (1, 2, 3). The pilot plant runs were metallurgically successful and preliminary engineering studies for a full scale operation were completed under contract by an outside engineering firm. Unfortunately, the net return projected at that time did not justify the proposed capital' investment. In the summer of 1973 the project was revived. The rise in selling price of copper over the previous ten years, compared to the projected operating cost of the leach plant, increased the calculated net return on investment with the most recent figures showing a 30% DCF. Basically, the reason for this favorable shift in profitability was that the cost for many of the reagents did not go up as fast in the previous ten years as did the selling price of copper. Using the Chemical Marketing Reporter costs, NaCN sold for 18.3¢/lb in 1963 and 20.75¢/lb in August, 1973. During this same period H2S04 went from $23.50 per ton to $35.90 per ton. In comparison, producer's prices for electrolytic copper were 31¢/lb in 1963 and 619 in 1973. Thus the price of copper went up 97% while the two reagents only increased 13% and 53%, respectively. The capital investment also escalated but, again, not to the same extent as the selling price of copper. These price differences no longer are valid' but they did provide justification for reexamining the project.

Jan 1, 1975

By Robert M. Lewis

Chemically, mica is a complex silicate of sodium, potassium and aluminum. There are no important uses of mica where the chemical analysis is important, except that in some uses of ground mica, the content of iron oxide present as an impurity must be kept to a very low limit. Muscovite mica is frequently found containing black and red "stain" as a homogeneous part of the books or sheets. In most cases this stain or impurity is magnetite or hematite. Some mica contains impurities deposited by infiltration. This is commonly a red stain, less often brown or white. The best mica is free from all such impurities, and the greater their content, the less value does the mica have.(1) It is because of these undesirable impurities that a large segment of the fine ground mica industry relies on weathered pegmatites and alaskite ores as a source of raw material. The mica concentrates obtained from these ores are relatively clean and require moderate beneficiation to meet color and density specifications. One need only to observe the stained and decrepitated condition of the mica recovered from mica schist to appreciate the challenge that processing this material presents. Despite these adversities there are several advantages to be gained by mining and processing mica schist ores. The mica content of these ores are considerably higher than the pegmatites and alaskite ores now being mined, often containing in excess of forty percent mica. This-higher grade mica feed should promote a lower mining and milling cost with its resulting competative advantage. With more rigid government

Jan 1, 1969

By VÍCTOR VÁZQUEZ-VÁZQUEZ, GUILLERMO TIBURCIO-MUNIVE, María M. Salazar-Campoy, JESÚS L. VALENZUELA-GARCÍA, OFELIA HERNÁNDEZ-NEGRETE

This study examines a process for the recovery of precious metals from difficult minerals that exhibit refractory characteristics to cyanidation: low extraction of metals and high consumption of leaching reagent. A mineral sample from Monte del Favor Mine, located in Hostotipaquillo, Jalisco, Mexico, was physically and chemically characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), fire assay and atomic absorption spectroscopy (AAS). Two stages of leaching were carried out, first to eliminate manganese from the sample using sodium sulfite (Na2SO3) as a reductive reagent along with sulfuric acid (H2SO4), and second to dissolve gold and silver with hydrochloric acid (HCl) and sodium hypochlorite (NaClO). The results show extractions of around 96 percent for manganese (Mn), 98.73 percent for silver (Ag) and 83 percent for gold (Au). The usefulness of high acidity and Na2SO3 to obtain better results in Mn and Ag leaching are discussed along with the roles that HCl and NaClO play in Ag and Au dissolution values.

By L. C. Bartel

Geologic features such as structure (faults, folds, fractures, etc.), water bearing zones, aquifers, pemeability variations, and porosity variations are important for mine planning and in situ energy recovery processes. Features important for planning a mine will be important for planning the recovery of energy by in situ processes. Various geophysical techniques might be used to obtain the necessary geologic information. In this paper, case histories will be discussed of the use of electromagnetic geophysical surveys at a potential underground coal gasification site and a potential tar sand oil recovery site to obtain pertinent geologic information. Results show that the controlled source audio- frequency magnetotelluric technique shows promise for mapping faults and natural fracture systems when there is a sufficient resistivity contrast.

Jan 1, 1982

By M. Deutsch

A common casualty of modern open pit mine optimization is the assurance that the resulting design is actually achievable. Optimized mine plans that consider value and a bare minimum of precedence constraints do not, in general, translate into practical, operational mine designs that can really be used in the field. Ultimate pits may come to a sharp point at the bottom. Schedules may require taking small parcels of material from many disparate areas of the pit in a single period. And grade control polygons may be ragged, narrow, and not minable with realistic equipment. In this paper all of these problems are addressed by encoding these three fundamental open pit mine optimization problems as maximum satisfiability problems. Maximum satisfiability provides a useful framework for problems that are non-linear and may guarantee the optimality that metaheuristics cannot. INTRODUCTION Open pit mines are large and complicated operations, which require significant initial and ongoing investment. A single mine may employ hundreds or thousands of people and creates substantial benefits for both the surrounding and global communities. Planning an operation of this magnitude requires a lot of effort and cannot be done optimally by hand. Mining engineers today rely on many techniques from operations research to guide decision making, and to maximize the value of the mine. Techniques including linear programming, metaheuristics, and network algorithms are all used to solve different problems throughout mine design and optimization. However, techniques based on Boolean satisfiability, including the optimization extension of maximum satisfiability, have not seen much use in mining despite being used in many other fields including electronics design, scheduling, and artificial intelligence. We claim that maximum satisfiability is a useful and meaningful way of expressing and solving optimization problems in mine planning. However, this technique does not come without challenges; the problem is NP-hard, and modern techniques for solving these problems can struggle with the number of variables and clauses that a typical mining problem requires. Also, some of the constraints that mining must contend with do not fit nicely into the satisfiability paradigm. Despite these challenges, we believe that maximum satisfiability provides a useful framework for considering operational constraints and expressing some problems that other techniques can't easily express. Maximum satisfiability can be solved exactly, yielding the true optimal answer which metaheuristics cannot guarantee. In this paper we show the applicability of maximum satisfiability to mining by specifying three fundamental problems in open pit mine optimization. We show how these fundamental problems can be formulated and how they can be extended within the framework of maximum satisfiability. For the remainder of the paper we first give a brief background on common elements between the three problems and an introduction to satisfiability. Then we tackle the three problems; the Ultimate Pit Problem, the Block Scheduling Problem, and the Grade Control Polygon Problem. In the Ultimate Pit Problem we specifically show how to extend the problem to support a minimum mining width – a coveted result for many mining engineers. We then discuss some of the complexities and shortcomings of this framework and possible research directions.

Jan 1, 2019

By Keith A. Heasley

The objective of this paper is to back-analyze the August 6th ,2007 collapse at the Crandall Canyon Mine in order to better understand the geometric and geo- mechanical factors which contributed to that collapse. In this work, the LaModel boundary-element program along with the best available information is used for the back- analysis. To initiate the analysis, a six step base model of the mining in he Main West area was developed. This base model included a step for each of the critical stages in the mining of this area. Next, calibrated values for the critical input parameters: rock mass stiffness, gob stiffness and coal strength, were developed and optimized based on the best available information. Finally, the model was used to simulate the final mining scenario. As a result of this back analysis , a number of conclusions can be made concerning the mine design and the August 6th collapse: 1) Overall, the area was primed for a massive pillar collapse because of the large area of equal size pillars, 2) The abutment stress from the active retreat sections and the adjacent longwall panels were significant contributors to the collapse, 3) From the modeling alone, it is not clear exactly what triggered the August collapse, although the active mining is a reasonable assumption.

Jan 1, 2012

By Takayoshi Otsuka, Taher Elsamni, Ashraf Bou-Krisha, Takaya Takimoto

"INTRODUCTION Tunnel is a closed space structure and it is necessary to ensure the sufficient time and route for safe evacuation for the tunnel users in case of a tunnel fire. In order to do so, damages and collapse of the tunnel linings and the secondary disasters can be avoided. Furthermore, the road tunnel is one of important infrastructural facilities and stopping its function for a long time for a tunnel fire could cause a great economic loss. Therefore, the tunnel structure shall be the one which can be repaired as soon as possible, and the fire protection methods need to be selected among those which enable the service to start as early as possible. The necessity of the fire protection works is evaluated for the tunnel structure with the consideration of the expensive tunnel construction cost and the economic effects of the tunnel service. Naturally, the fire protection works, which can protect the tunnel linings from the tunnel fire with small repairs, are inevitable. Design engineers of the fire protection works estimate the scale of fire from the degree of damages on the linings and its repair cost, the effect of fire extinguishers placed inside of the tunnel, the secondary disasters in accordance with the tunnel lining damages if any, and the ratio of fire protection cost calculated from tunnel operation cost. Based on this information, the engineers design the fire protection works according to the permissible limits Among the design cases of the tunnel fire protection in Japan, as shown in Table 1, there is no cases that used the fire temperature-time curve to design the fire protection works for large fire caused by vehicles catching fire. However, the most of cases used 30-60 minutes for fire duration based on the entry prohibition of dangerous goods carrying vehicles or the effect of early fire fighting. This paper will study the variation between different methods used for fire protection in road tunnel in Japan to evaluate them and try to found some recommendations. Especial l care will be attention to Polypropylenes (PP) which is starting to be applied lately."

Jan 1, 2016

By Howard E. Banta

From Alaska to Florida and California to Maine, the National Forest System (NFS) is host to unprecedented levels of prospecting and development. The NFS is large (191 million acres), geologically attractive from the mineral standpoint and relatively unexplored. Significant recent finds and developments involve silver, gold, platinum group metals, molybdenum, cobalt and phosphates. Exploration and development are closely regulated, but most of the NFS is open. The Forest Service endeavors to be a good host to the mineral industry, but increasingly is asked or forced to delay or disapprove mineral projects to protect the environment.

Jan 1, 1984

By Barbara H. Carroll

In order to rapidly evaluate an area for its mineral potential, a reconnaissance exploration program generally includes the following: 1. Outlining an area of interest 2. Identifying known mineral deposits 3. Bibliographic search of the literature 4. Evaluation of geochemical and geophysical surveys 5. Compilation and review of geologic maps The information now available from various government agencies regarding the mineral deposits, geology, and geochemistry may be integrated and used as a tool to rapidly evaluate an area before the field season. The databases most commonly used in the United States are the USBM MAS/HILS system and the USGS MRDS system for their information on mineral deposits; GEOREF and GEOARCHIVE for bibliographic information; and NURE data for the geochemistry and geophysics. In conjunction with the project geologist, this information may be used to plot known deposits and their geochemical signature as well as any other areas of like signature for further examination.

Jan 1, 1985

By James O. Glanville

Ice frozen from a dilute chemical solution is mechanically weaker than ice frozen from pure water. This phenomenon is the basis of a practical method for reducing the strength of a mass of frozen coal. If a chemical additive is applied to moist coal, prior to its shipment during freezing weather, the resulting frozen coal can be more easily broken than in the absence of the chemical additive. This greatly expedites the unloading and handling of coal during winter. There has been considerable research into the nature and mechanical strength of ice frozen from various solutions. The literature relating to this process has been reviewed as has the literature relating to the chemical treatment of coal and mineral particulates. Some important articles are discussed and speculations are made about the nature of the ice-weakening process. A laboratory evaluation of the effects of chemical additives on the mechanical strength of ice and frozen coal has been made. An apparatus designed for this purpose is described, and some results obtained with it are discussed.

Jan 1, 1980

By Edgar F. Cruft

It is sometimes said that "mines are made, and not found". I rather doubt that the exploration geologist would be overly sympathetic to that statement, and, of course, like most one-liners it is only partly true. As an explorationist who has been involved in building his own company over the last ten years, and by necessity has become a financier, I can appreciate what real grains of truth are in that statement, however. Because technical people are seldom taught financing in their basic training, and because they are usually not involved in it until at quite a senior level in their careers, the whole field often acquires a certain mystique. The engineering professions have too often believed financing is the province of the accountant or financial executive and just as we in the technical world are often too quick to bristle if the latter try to tread on our domain, the opposite can just as easily be true. Unfortunately, this is another example of a compartmentalized individual, and that is one thing the successful financier cannot be.

Jan 1, 1979

By M. J. Laurila

The concentration of low grade iron ores to pellets or sinter fines suitable for blast furnace feed or direct reduction is highly energy intensive and costly in terns of both size reduction and separatory processes. Large equipment with high throughputs are required to make the fine grinds and multi-stage separations economical. Control of these circuits is essential to producing a high grade product. As a result, iron ore concentrators possess some of the more sophisticated instrumentation for process control in the mineral dressing industry. These instruments must characterize flowstreams of up to 8,000 gpm where 80% of the particles are less than 50 µm. The past decade has been one where enormous strides have been made in automated control of iron ore plants. This paper reviews state-of- the-art control systems for crushing, grinding, magnetic separation, froth flotation and sizing/classifying circuits. Trends toward computerization and plant automation in response to a dismal outlook for North American steel production are also examined.

Jan 1, 1984

By Earl Rau

Introduction Will cogeneration be a major power source in the future? The location of electric power generating plants has changed. In 1900, more than 50% of electricity was generated by industrial plants. Since then, industrial plant generation of electricity greatly decreased to 17% in 1950 and to only 3% in 1980. Changing economics in electric power generating costs, though, may allow cogeneration to reverse this trend. Cogeneration has been defined as the simultaneous production of electric (mechanical) and thermal energy from a single energy source. Some applications are considered to be byproduct generation of electricity from industrial, thermal operations. Cogeneration is not new to the mining and minerals industry. Smelters and steel mills have used waste heat to generate electricity. Public Utilities Regulatory Policies Act of 1978 The potential for increased industrial cogeneration of electricity is related to the March 9, 1978 enactment of the Public Utility Regulatory Policies Act (PURPA). The US Supreme Court ruled that PURPA is constitutional. The court upheld requirements that utilities interconnect to cogenerators. It also ruled that 100% of avoided costs be used as the guideline for electricity sales by a qualifying facility (QF) to a utility. The state of New York established a floor price $0.06/kWh for electricity sales from a QF to a utility. It is obvious, then, that a cogenerator must first establish price and then become a qualifying facility in order to sell electricity to a utility. Proposed cogeneration plants The estimated industrial cogeneration potential for the years 1986 to 2000 is 9500 to 25,000 MW. Industries represented in this cogeneration estimate are pulp and paper, petroleum, chemicals, food, textiles, rubber, plastics, steel, lumber and wood, cement, glass, metal fabrication, and industrial parks. A cogeneration plant has been proposed for the Union Carbide chemical plant in Institute, WV. A steam turbine/generator would be installed to replace the pressure-reducing valve in the 2.7 MPa (400 psig) header. Scott Paper Co., Mobile, AL, proposed a cogeneration plant using a coal- and wood-fired boiler and a turbine/generator to produce process steam and electric power. A cogeneration system has been proposed for a large oil refining plant. A pulverized coal boiler would produce high-pressure steam to operate a turbine, generator. The exhaust steam from the turbine will go to the process and an existing turbine. Kansas City, MO's Armour meat-processing plant has proposed a cogeneration plant. This proposal is to use a natural gas or oil-fired, gas-driven turbine and a generator. The waste heat from the gas turbine would go to a heat recovery boiler for use as process heat. Dade County, FL is implementing a central energy system to supply electricity, air conditioning, and domestic hot water for five buildings in downtown Miami. The cogeneration system is to provide flexibility, to optimize fuel use efficiency while serving the variable thermal demands. Generation of electricity from municipal waste is not considered to be a cogeneration process but is covered by PURPA. Special considerations are provided for waste/electric power generation to encourage the development of these systems. ?

Jan 7, 1987

By Erik Klohn

The El Soldado copper deposit occurs in volcanic rocks of alkaline affinity of Lower Cretaceous age. The orebodies are discordant and show strong structural and lithological control. The mineralizing event was accompanied by hydro- thermal alteration expressed as carbonatization, silicification, and chloritization. Individual orebodies contain bornite-chalcopyrite cores which are surrounded by haloes dominated by chalcopyrite and pyrite respectively. The sulfur isotope composition of copper sulfides strongly suggests the sulfur is of magmatic origin. Fluid inclusion studies show the mineralizing fluid to be a highly saline NaC1-CaC12, brine. No evidence of boiling was found. The deposit is most likely of epigenetic origin. Hydrothermal fluids were produced during crystallization of a sodium rich trachytic magma during the waning stages of an episode of alkaline magmatic activity. Similar copper deposits along the Chilean Coastal Range may also be associated with alkaline host rocks.

Jan 1, 1986

By K. Chandrasekaran

Carbon-in-Leach (CIL) is conventionally used in gold processing operations when preg robbing components are present in the ore. CIL process is becoming attractive even in other situations when preg robbing is not a factor. This paper discusses the situations in which the CIL circuit can be applied. The results of Leach/CIP and CIL circuits at Newmont's Mill No.2, 4 and 5 are presented for comparison. Newmont's Mill No. 4 was initially designed for a throughput of 4500 tons per day. The mill is presently operating at an average throughput of 7300 tons per day without significant changes to the original design. The design considerations of the Mill No.4 CIL circuit are discussed.

Jan 1, 1991