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By Surendra K. Mishra

The increasing volume of wastes being generated by industry is a legacy of the industrial revolution and subsequent industrial growth. Social and regulatory pressures have been mounting on industry to improve its waste management practices. In many industrial sectors, waste disposal has been the only method of waste management. Land farming, underground burial, deep wells and incineration are still practiced. Often, concentration and volume reduction of waste streams are also practiced to reduce the waste management costs. In the recent years, there has been emphasis on waste minimization. Since the 19th century, industry has practiced recycling of usable resources as a way of handling unwanted byproducts. The mining industry has recovered or extracted economic minerals from tailings for decades. For example, during the gold rush period of 1970s, extraction of gold from tailings dams became economically attractive. Similarly, when it was economical, coal and shale fractions have also been recovered from tailings and refuge materials for commercial uses. In the steel industry, with the development of new furnace technology, recycling of flue dust and scrap iron was practiced as early as in the 19th century. Before 1900, there was little incentive for the industry to reduce the waste volumes. Manufacturers, however, did see a rationale for adopting profit-increasing techniques. They made an effort to recover and recycle economic materials from waste sources. One of the pioneering examples of resource recovery is the coke making industry. As the industry was market driven, products recycled from coke batteries included ammonia for use in fertilizers, gas for power generation and heating, and tar for road construction, wood preservation and roofing. Tar had been avery troublesome waste byproduct. But it quickly became a valuable chemical raw material, providing the foundation for Germany's dominance of the world's dye and medicine markets before World War I. Similar trends evolved in the chemical industry. In the context of current environmental regulations and escalating mining and processing costs, recycling of re- [ ] sources is becoming economically more attractive. Solid and liquid wastes generated by industries contain a range of inorganic and organic contaminants. Among these contaminants, metals and hydrocarbons form major groups. Treatment of these wastes is essential to meet regulatory disposal requirements. In the recent years, based on the principles of chemical and mineral process engineering, processes have been developed to treat these industrial wastes. This article reviews some of the processes that have made impacts and have proven to be effective at commercial scales.

Jan 1, 1999

By Robert W. Bartlett

Pretreatment of sulfidic refractory gold ore by biooxidation in coarse-crushed ore heaps is a promising new technology, especially for low-grade ores that cannot afford pressure leaching or roasting. An algebraic equation for determining the economically optimum biooxidation of the sulfide minerals in the ore is provided that is based on the empirical biooxidation rate constant for the ore, the project's financial discount rate, the ore grades of both refractory and non-refractory gold, and the gold price. Then, the economically optimum duration of bioheap pretreatment, t$, is determined from its logarithmic relation to the optimum fractional extent of ore biooxidation, F$, through the ore's biooxidation rate constant. In doing so, it is assumed that the ore is adequately crushed and amenable to bioheap pretreatment and that the cumulative oxidation of the ore with time is known from ore testing so that the rate constant can be determined.

Jan 1, 1995

By Dale K. Nash

The authors have developed a com¬puter-assisted critical path planning and scheduling model to help reduce time required to move longwall mining units. The model includes time constraints and limited resource constraints, such as manpower, machinery, supplies, work space, and transportation routes. Outstanding results were achieved on the first move to which the computer-model pas applied; e.g., downtime due to the move was cut by 50%. The model and the schedules developed using it provide an excellent blueprint for future moves and have led to significant savings in time and costs for Emery Mining Corporation, Huntington, Utah.

Jan 1, 1983

This paper summarizes the process development behind the design of three different types of paste fill plants at operating Canadian hard rock mines. Each application has a unique paste backfill mix and process which utilizes the materials economically available to the mine site. The different plants produce paste fill composed of base metal tailings, a blend of recovered disposal pond tailings fines and alluvial sand, gold ore tailings, and a blend of gold ore tailings and alluvial sand. This work has led to the joint development by Inco and GL&V Ontario of the compaction storage mechanism for the de-watering of mill tailings to a paste consistency.

Jan 1, 1994

By Barnaby J. Watten, Sibrell. Philip L., Brian J. Vinci, Andrew E. Friedrich

We evaluated a new process for remediation of acid rock drainage (ARD). The process treats ARD with intermittently fluidized beds of granular limestone maintained within a continuous flow reactor pressurized with CO2. Tests were performed over a thirty day period at the Toby Creek mine drainage treatment plant, Elk County, Pennsylvania in cooperation with the Pennsylvania Department of Environmental Protection. Equipment performance was established at operating pressures of 0,34,82, and 117 kPa using an ARD flow of 227 L/min. The ARD had the following characteristics: pH, 3.1; temperature, 10 OC; dissolved oxygen, 6.4 mg/L; acidity, 260 mg/5; total iron, 21 mg/L; aluminum, 22 mg/L; manganese, 7.5 mg/L; and conductivity, 1400 uS/cm. In all cases tested, processed ARD was net alkaline with mean pH and alkalinities of 6.7 and 59 mg/L at a CO2 pressure of 0 kPa, 6.6 and 158 mg/L at 34 kPa, 7.4 and 240 mg/L at 82 kPa, and 7.4 and 290 mg/L at 117 kPa Processed ARD alkalinities were correlated to the settled bed depth (p<0.001) and CO2 pressure (p<0.001). Iron, aluminum, and manganese removal efficiencies of 96%, 99%, and 5%, respectively, were achieved with filtration following treatment. No indications of metal hydroxide precipitation or armoring of the limestone were observed. The surplus alkalinity established at 82 kPa was successful in treating an equivalent of 1136 L/min (fivefold dilution) of the combined three ARD streams entering the Toby Creek Plant. This side-stream capability provides savings in treatment unit scale as well as flexibility in treatment effect. The capability of the system to handle higher influent acidity was tested by elevating the acidity to 5000 mg/L with sulfuric acid. Net alkaline effluent was produced, indicating applicability of the process to highly acidic ARD.

Jan 1, 2000

By Hassan Madani

Kushk lead-zinc mine is located in central part of IRAN. The mine is owned by Bafgh Mines Co., which is a nationalized company. Exploration results show that ore occurs in the area that extends for 800m length and 180m depth. The approved, probable and possible reserves of the mine is 900,000 tons, 1,120,000, tons and 1,450,000 tons respectively with average grade of 17.7% zinc and 4.3% lead. The total annual output of the mine all was by underground mining, is in the order of 100. 000 tons. The main entry to the mine is via an inclined shaft with a cross-sectional arp of 8 m2, length of 263m which dips at 20°. The ore is mined mostly by sublevel stopinq method. The major difficulty in ventilating the mine was that related to spontaneous combustion of pyrite, which was more serious in some parts of the mine than others. In order to reduce this risk, a new ventilation system for the mine was designed, using 4 exhusting fans.

Jan 1, 1991

By Claus Becker

The Mixshield is a tunnelling machine for water bearing soft soils. Developed on the basis of the Hydroshield, it extents the application of this machine to cohesive soils. The design of the drum-type machine allows three different applications 1. As shield with liquid supported face and hydraulical mucking 2. As Compressed-Air-Shield 3. As Earth pressure balanced shield. The Mixshield is employed on three big contracts 1. a 6.3 km ring tunnel in Hamburg, outer diameter 5.95 m, with a new developed segmented concrete lining 2. a 1.9 km pipe-jack job near Cologne, o.d. 3.6 m 3. Metro Lot 3 in Lille/France, o.d. 7.7 m, 3.2 km long with segmented concrete lining and a most sophisticated separation-plant The site experiences will be reported.

Jan 1, 1987

By P. I. James, M. R. Baker

This paper examines new copper production from waste-grade ore using Blue Planet Strategies’ DEMET™ (Dynamic Electrode Mining Effluent Treatment) technology, which aims to bridge the practical weak pregnant leach solution (PLS) processing gap in heap leach-solvent extraction/electrowinning (SX/EW) operations by electrochemically removing metals from weak streams and generating product streams strengthened in target metals in a functional analog to SX. Weak PLS treatment was studied and used to estimate the economic and production impacts for a representative hypothetical brownfield copper heap leaching and DEMET-augmented SX/ EW operation to utilize "waste ore." Copper removal at 86% plating efficiency to below 0.1 g/L copper with power consumption of 0.55 kWh/lb copper and product strengths of over 10 g/L copper are presented. Modeling yielded approximately $2/lb total copper production and = $1/lb treatment costs with an immediate operation gross margin increase of 12% for the augmented brownfield. Potential mine life extension with an average 38% gross margin on "waste ore" augmented production at copper values of $3.25/lb was also indicated.

Jan 1, 2014

By R. L. Frederking

Geological remote sensing is, "....the study of the Earth utilizing electro-magnetic radiation (EMR) which is either reflected or emitted from the land surface in wavelengths ranging from ultra-violet (0.3 micrometre) to microwave (3 metre)."1 Selected examples which illustrate a variety of successful geologic applications include lithologic mapping, 2 engineering soils mapping,3 tectonic interpretation,4 and mineral and petroleum exploration.5 This report examines the applicability of remote sensing for bauxite exploration in northeastern Mississippi. Specific objectives were to map lithologies of northeastern Mississippi from LANDSAT imagery, to determine the utility of LANDSAT imagery for delineating and mapping known deposits of bauxite, and to discover and map new bauxite deposits.

Jan 1, 1977

By Peter L. Comanor

At Getchell, Nevada a thousand tons per day mill for extracting gold from an ore containing orpiment and realgar was operated several years until early 1967. A cyanide process with a roaster was used in the processing of the ore. Mill wastes were contained in tailings ponds, in which the concentration of arsenic, currently, is one per cent or higher, Studies were conducted determining the effect of the tailing wastes on the Upper Sonoran vegetation of the area. Grid and line-intercept techniques were employed to obtain botanical informatics of the area surrounding the tailings ponds. Data of the per cent ground cover, species frequency, and plant vitality as a function of distance from the tailings ponds was collected. The data was compared to other botanical data collected from a control site outside the influence of the tailings ponds. In an attempt to isolate naturally occurring factors for varying plant communities from hose induced by factors derived from the close proximity of the tailings, soil cores were taken along the line-intercepts at intervals of 30 meters. The cores were analyzed for several compounds and elements needed for growth, or known to inhibit growth. Specific physical parameters of the soil samples were also taken. The paper describes the impact made by mill wastes containing large amounts of arsenic on the Upper Sonoran vegetation of the Getchell region. Described in detail are the techniques used to make the correlations between the plant communities and the influences of mill wastes.

Jan 1, 1974

By Steven W. Hunt, Gregory C. Baker, Glen J. Rorison

Microtunneling methods were utilized beneath pile-supported clarifier basins to replace settlement damaged sludge drain lines at the Jones Island Wastewater Treatment Plant in Milwaukee, Wisconsin. To minimize the risk of blockage and expensive recovery of a microtunnel boring machine against pipe piles or construction debris, a Soltau RVS 80 was utilized. This machine allowed the alignment to be initially bored with guided 114-mm diameter rods to ensure proper alignment and lack of obstructions. Casing pipe was then installed by jacking 1-m long, 305-mm diameterclay pipe along the rods and behind an auger head. This case history also discusses how 2.4-m diameter precast concrete pipe was used as a one-pass sinking caisson for workshafts and new cleanout manholes.

Jan 1, 2001

By J. Holmes Armstead, John L. Dobra

This paper examines some lesser known risks in foreign investment by U.S. companies that derive from international judicial activism by U.S. courts and the potential for extending U.S. anti-trust regulations to companies&apos; foreign operations. The discussion of international judicial activism reviews the implications of the U.S. Second Circuit Court&apos;s ruling in the Union Carbide/Bhopal case for U.S. companies investing abroad and the discussion of extending U.S. anti-trust regulations focuses on proposals coming out the Clinton administration&apos;s Justice Department.

Jan 1, 1996

By H. W. Judges

A 16.5-kt/day underground molybdenum mine is being developed at Questa in Northern New Mexico by Molycorp, Inc., a wholly-owned subsidiary of Union Oil Company of California. Construction of the underground mine began in 1979, and first production is scheduled for early 1983. A gravity block caving method has been selected for mining the ore. Access to the mine will be through a service shaft, development shaft, and a conveyor decline. The shafts are being sunk under contract and the conveyor decline is being driven by Molycorp. The driving of the decline began in February, 1979 with a 10-man mining class. By the first of May, enough men had been trained to begin a continuous operation and by March 1, 1980 the face had reached the 1500 m mark. The heading is being driven with trackless rubber-tired equipment using a three-boom drill jumbo, 2.7 m3 LHD units and 7.3 m3 trucks. Ground support has been by rock bolts and wire mesh, followed by Fibercrete. A 16.5-kt/d underground molybdenum mine is being developed at Questa in northern New Mexico by Molycorp, Inc., a wholly-owned subsidiary of Union Oil Company of California. The new $200-million underground project will revitalize mining and milling activity at Questa, where small scale underground mining first began in 1920. Large scale open-pit mining was initiated in 1965 but now, because of the high stripping ratio, surface mining is being phased out. Construction of the underground mine began in 1979, and first production is scheduled for early 1983. The company expects full capacity - 9 Gg of molybdenum per year - to be reached in 1984.

Jan 1, 1980

By J. M. Barker

New Mexico is the leading domestic producer of perlite, a hydrated volcanic glass that can be expanded thermally to form a white, very porous, lightweight material. The United States is the leading consumer and producer of perlite in the world (Pettifer 1981). New Mexico produced, at five mines (Fig. 1), about 86% of all domestic crude ore mined in 1984 (Meisinger, 1985). Perlite is mined in 6 other western states, ore is expanded in 33 states, and the expanded ore is consumed in all states (Meisinger, 1985). Gross value of domestic ore mined in 1984 was about $16,500,000 (FOB mine; Meisinger, 1985) with much value added by expansion and processing prior to sale to end users. In contrast to the ubiquitous nature of perlite products in the U.S. economy, facilities for testing perlite ore, expanded perlite, and perlite products are notably lacking on a commercial, cost-effective, or readily accessible basis. The New Mexico Bureau of Mines and Min¬eral Resources (NMBM&MR) established a perlite¬testing facility in 1984 to mitigate this lack and to further the mining of perlite in the state.

Jan 1, 1985

By Bernard A. Grand, Gary A. Almeraris

This project involves the reconstruction of a 1,100 ft. long by 75 ft. wide segment of an existing 4 to 5 track subway under Northern Boulevard in the Borough of Queens in New York City. The project includes widening the existing subway to permit the construction of new inbound and outbound subway (T1 and T2) ramps adjacent to and under existing operating tracks. The plan of the project is shown in Fig. 1. Existing tall buildings along the job site and a contaminated groundwater plume under an adjacent rail yard required construction of slurry concrete walls along the east and west construction limits. Groundwater cutoff across the north and south construction limits of the subway was achieved by jet grout walls built across the subway invert slab between existing track and third rails. The work involved dewatering the construction site to a depth of about 50 ft. below street grade. This is a four year project and includes extensive work to maintain and protect subway and vehicular traffic of over half a million commuters a day through the work area. The project cost was $160,000,000.

Jan 1, 1999

By S. McMurray

INTRODUCTION Towards the end of the 1890s the attention of a prospector by the name of Thomas Cullinan was drawn to the occurrence of alluvial diamonds east of Pretoria. Persistent prospecting work by Cullinan led to the loca¬tion of the source of these diamonds-a kimberlite pipe on the Elandsfontein farm. Cullinan eventually acquired the property in 1902, and during an extensive evaluation program outlined the largest diamondiferous pipe in South Africa on which the Premier mine was established. Worldwide attention was drawn to this mine in 1905 when the Cullinan diamond, which weighed 3106 carats and is by far the largest gem diamond ever discovered, was recovered. Premier mine operated with varying success until 1932 when the worldwide depression forced it to close. In 1945 the mine was reopened and since then has been a major producer of gem and industrial diamonds. During the early 1950s exploratory drilling revealed that below the 370-m level the pipe had been completely cut off by a younger gabbro sill. This sill has created major mining and metallurgical problems but the existence of vast reserves of high grade ore below it justi¬fied the establishment of virtually a new mine below the sill. Detailed planning of below-the-sill mining is nearing completion and the development of the first mining block (the L1 block) is well advanced. A full discus¬sion of this block follows. GEOLOGY OF PREMIER MINE Pipe Morphology and Country-Rock Geology As can be seen in Fig. 1, Premier mine is an elon¬gated oval shape with a long axis of 900 m on the surface and a short axis of 450 m. The pipe has a surface area of 32 hectares which decreases progres¬sively with increasing depth, so that 500 m below the surface the area is reduced to 22 hectares. The contact between the kimberlite and the surrounding country rock is sharp, with an average angle of dip of 1.48 rad (85°). From the surface down to approximately 350 m, the country rock is a felsite which grades downwards into a norite. In general both rock types are hard and massive, the felsite in particular being poorly jointed. This characteristic combined with other factors results in an extremely stable open pit, and near-vertical side¬walls are currently being maintained. The norite in general is competent but is heavily jointed in some areas resulting in very blocky ground which creates localized tunnel support problems. In the southeastern area below the sill a zone of highly altered and very unstable norite, which has also created localized sup¬port and development difficulties, lies adjacent to the pipe contact. Kimberlite Geology The Premier pipe is a complex multiple intrusion which contains in the region of 15 separate types of kimberlite, most of which are volumetrically insignifi¬cant. On a simplified basis three major types can be identified which correspond to three separate phases of intrusion. They are: Brown Kimberlite: This represents the first phase of intrusion and now occupies the eastern part of the pipe. In plan the brown kimberlite has a crescentric shape resulting from the intrusive relationship with the younger gray kimberlite which lies to the west. The brown kimberlite increases in relative area with increas¬ing depth which is a favorable factor for future mining operations since this kimberlite is the richest area of the mine, having an average grade of 70 carats/ 100 t. Below the sill this rock disintegrates extremely rapidly when exposed to air or water, to form a fine gravel-like material. This characteristic is due to a high montmorilonite clay content. As is common with clay minerals of this type, water can be absorbed into the crystal lattice with a resultant increase in volume which causes the physical decomposition of the rock. The presence of this decomposing kimberlite was a major factor governing the choice of a mining method, as well as development and tunnel support techniques. Gray Kimberlite: This is the most abundant type and represents the second major phase of intrusion. The diamond content is variable depending on the amount of waste rock dilution, and in general the rock is stable and non-decomposing. At the time of formation of Premier, the surface rock type was Waterberg quartzite, a rock formation which has subsequently been removed from this area by erosion. The explosive extrusion of the gray kimberlite caused extensive brecciation of this rock and while the kimberlite was in a mobile state huge masses of quartz¬ite, amounting to tens of millions of tons, slumped into the pipe. This quartzite became concentrated in the central area of the mine and has been a major mining problem throughout the history of Premier since, due to the irregular distribution of the quartzite, effective selective mining has never been possible. The quartzite is therefore extracted with the ore and has a significant dilution effect on the overall grade. Black Kimberlite: In the western part of the pipe a circular, pluglike body of kimberlite is intruded into the gray kimberlite. This plug consists mainly of a hard, dark-colored rock known as black kimberlite, but also contains a number of minor kimberlite variet.ies as well as nonkimberlite carbonate dikes. The Gabbro Sill The sill averages 75 m in thickness and within the confines of the pipe consists of 52 million t of rock. On average the major dip is 0.34 rad (20°) to the northeast which is across the short axis of the pipe, the range of dip being from near horizontal up to 0.52 rad (30°). Due to the pronounced dip, the sill is encount¬ered over a vertical distance of 175 m with the highest upper contacts on the 355-m horizon and the lowest bottom contact on the 530-m horizon.

Jan 1, 1982

By K. Norris

The Amax Gold Guanaco mine is located in the Atacama Desert, approximately 260 km southeast of Antofagasta, Chile. The 6,000 tpd leach operation produces approximately 90,000 oz of gold, and 360,000 oz of silver per year. Production began in 1987, and the operation has been managed by Amax Gold since 1992. The mine has been plagued in the past by high operating costs and low production. Several significant changes have been made to the operations which have resulted in lower costs and higher operating efficiencies. A review of these changes is presented herein.

Jan 1, 1997

Early experiences suggested autogenous mills were difficult to operate and consumed substantially more energy than conventional rod/ball mill circuits. As our understanding has increased and the technology has matured this perception has changed to the point where most new comminution circuits are ag/sag based. In addition many operators have replaced existing conventional circuits with this technology. The JKMRC has been studying ag/sag mills for over 20 years. During this time it has amassed what is probably the single largest and most detailed data base of pilot and full scale mill operations in the world. This has been used to help develop and refine its cur- rent commercially available mathematical model of ag/sag mills. A decade of its application has greatly helped simplify both design and operation of ag/sag milling circuits as well as helping to promote the effective use of recycle crushing, secondary crushing and closed-circuit operation. This paper describes the development of ag and sag milling in terms of our understanding and the evolution of the technology. In addition the application of mathematical modelling and simulation in designing and operating efficient circuits is described with the aid of practical examples.

Jan 1, 1998

By S. S. Klima, D. E. Pollock, J. A. Organiscak

"Airborne respirable coal dust capture by water sprays or wet scrubbers has been studied and developed over many decades as an engineering control to reduce dust exposure in coal mines and combat coal worker pneumoconiosis. Empirical relationships and deterministic models for particular dust capture experiments have previously been devised to show the key parameters involved in airborne coal dust capture. Many of the results from these models show that the significant parameters related to airborne dust capture are water spray pressure, water quantity, water droplet size, relative water droplet-to-dust particle velocity, and total operating air pressure of the scrubber. However, many airborne dust capture efficiency relationships and models developed for particular experiments cannot be readily applied to forecast the dust collection efficiency of different spray and scrubber design configurations, which rely on several key dimensional engineering measures. This study examines engineering measures from previous water spray and wet scrubber experiments conducted by the U.S. National Institute for Occupational Safety and Health (NIOSH) and the U.S. Bureau of Mines (USBM) to develop empirical models for wet collection of airborne dusts. A dimensionless empirical model developed for predicting airborne dust capture efficiency of water sprays and wet scrubbers is presented. IntroductionWater sprays have been one of the earliest mainstay engineering controls used to suppress respirable dust in underground coal mines. Some of the earliest reports of water spray usage on continuous mining machines indicated respirable coal mine dust reductions of 20 to 60 percent (Kobrick, 1970). Not long after the enactment of the 1969 Coal Mine Health and Safety Act, the U.S. Bureau of Mines (USBM) and others conducted extensive research into water spray and wet scrubber systems to control respirable dust in coal mines. The primary aspects of water spray dust control included prewetting for dust prevention, localized ventilation redirection and airborne dust capture, which are summarized in handbooks or best-practices guides (Kost, Yingling and Mondics, 1981; Kissell, 2003; Colinet et al., 2010). Initially, underground studies were conducted to identify the primary sources of dust during the mining processes and effective dust controls (Courtney, Jayaraman and Behum, 1978; Jankowski and Organiscak, 1983). Laboratory research systematically studied ventilation and airborne dust capture effects of water sprays and scrubbers to improve their application in underground coal mines (Tomb, Emmerling and Kellner, 1972; Divers and Janosik, 1978, 1980; Grigal et al., 1982; Ruggieri et al., 1983; Jayaraman, Jankowski and Kissell, 1985; Volkwein, Ruggieri et al., 1985; Jayaraman, Schroeder and Kissell, 1986; Divers, Jankowski and Kelly, 1987; Jones and James, 1987)."

Jan 10, 2018

By Lawrence P. Kennedy

The Lynne deposit is a volcanic-to volcaniclastic-hosted, Zn-Pb-Cu-Ag orebody located in the early Proterozoic magmatic terrain of northern Wisconsin. As of February 1991, core drilling has partially delineated a multi-million ton, near-surface, disseminated to massive sulfide deposit. The deposit is hosted by a gently dipping sequence of fragmental rhyolites, felsic tuffs, less abundant dacite to andesite flows, and fine-grained volcanic sediments. The deposit is broadly conformable With the host rock stratigraphy, but the ore zones thicken and coalesce in the central part of the deposit.

Jan 1, 1991