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By James L. Kelley

The Twin Buttes Mine, one of the more recently developed large copper mines in the United States, is in the Pima Mining District about 25 miles south of Tucson (Figure 1). Other copper producing mines in the district are the Esperanza-Sierrita mining operations, five miles to the southwest and the Pima and Mission Mines, seven miles to the north. Copper metal production from the Pima District in 1974 totaled 276,728 tons and the Twin Buttes Mine's share was 46,473 tons or about 17%.' The district's copper production was 31% of Arizona State's production and nearly 17% of the production from the United states in 1974. The Pima District thus ranks as one of the major copper producing areas in this country.

Jan 1, 1976

By W. F. McDermott

The transportation of solids by pipeline is not new. In 1891 a United States patent broadly covering a method of pumping coal with water was granted to W. C. Andrews. His pilot plant was constructed on what is now the site of the New York Public Library in Manhattan. His process was applied to pumping coal mine waste back into the worked out portion of coal mines. On October 26, 1967, the world's first long distance iron ore slurry line was put into service by Savage River Mines. The commissioning of this 5.0 million dollar installation climaxed three years of development, testing, and construction and proved the Company's faith in pioneering this unique transportation method for iron ore. This paper will discuss some of the more pertinent items in connection with that three- year period. Also to be discussed will be the operation of this line during the past eleven months.

Jan 1, 1968

By G. S. Austin

Soil next to an abandoned smelter near Socorro, New Mexico, has the highest Pb concentration in the clay-size fraction, although this fraction accounted for only 1 to 3 wt. % of the soil. The depth of contamination was determined in areas relatively undisturbed since the smelter was abandoned about 98 years ago. Lead concentration drops to background levels below a depth of 3 inches. A mineralogical examination of the fine-size fraction of Pb-contaminated soils revealed an absence of crystalline Pb compounds. We conclude that Pb is present either as amorphous phases or adsorbed on the surfaces of soil particles. Yet, because of the alkalinity of the soil, the movement of Pb-bearing particles controls Pb mobility, not chemical transport in solution. Plant material from the site contained elevated Pb levels that increased as the amount of Pb in the soil increased. Of the types of material tested, rabbit bush showed the greatest increase of Pb levels. Lead levels were highest in rabbit bush roots, whereas levels in creosote were highest in foliage. Levels in cactus varied. The amount of Pb due to dust incorporated in plant tissue is almost negligible compared to the amount absorbed through the plant vascular system.

Jan 1, 1992

By M. Sandin

According to the world bank1, the mining industry consumes up to 11 percent of global energy use. In comparison, 70 percent of mining projects from the six largest mining companies operate in water-stressed regions. To steer the direction of the process industries toward more sustainable practices, more than 40 governments have adopted a price on carbon. This measure includes additional taxes on the use of fossil fuels, trade programs, new standards for renewable energy, energy efficiency mandates, more stringent emissions regulation, carbon offsets, etc. This emphasis is also supported by investors shifting their priorities to reduce risk by focusing on long-term plans, including environmentally friendly operations. The metals and mining industry is at the core of the green energy mix and electrification of vehicles. This new trend creates an astronomical increase in demand for minerals. Under a 2-degree scenario, according to the latest analysis from the world bank, as new energy technologies continue to grow, it is expected that all minerals to double in demand, and the distribution of these materials will depend on their application. • Solar panels, will account for 87% of the aluminum demand, and more than 95% of silver • Wind turbines and geothermal plants will require 98% zinc and 64% titanium. • Solar and wind energy alone will demand more than 74% of the global supply of copper, and this is without considering wiring or other infrastructure to connect the grid • Battery storage accounts for 100% of the graphite and lithium demand. (Hund, 2020) • Other materials, such as nickel and steel, are also projected to more than double in demand as they are cross-technology minerals. These materials require a manufacturing process that is accountable for the emissions proper of the transformation process. It requires that these processes move from a hindsight mode focused on reporting to a forecasting mode based on run-time measurement of GHG emissions. This is a critical first step in companies realizing an economic return for doing the right thing for the environment and their communities.

Feb 1, 2023

By Chee Theng

"Mining professionals are a resilient lot. Sure, copper prices are dismal, permitting processes seem interminable and the top mining companies are shedding jobs like a Shetland sheepdog sheds hair. All the more reason to hone technical skills, reconnect with old contacts and get one’s finger on the pulse of the industry.More than 400 did just that in the balmy sunshine and among the saguaro cactus of the Tucson venue of the SME Arizona Conference.Giving the keynote speech was Patrick Merrin, vice president at Hudbay Minerals (see box), while the luncheon speaker was University Distinguished Professor Mary Poulton, director of the Lowell Institute for Mineral Resources at The University of Arizona.“Attendance was great, especially given the copper price,” said Ta Li, vice president of business development at Tetra Tech and 2001 SME President. “The luncheon speaker was one of the better ones in recent years. Her talk contained a lot of fresh ideas, and practical versus theoretical concepts.”Talk about values, not economicsPraise was unanimous for Poulton, who gave a thought-provoking talk on “The New Face of Mining: The Culture Change for Compatible Mining.” Corporate social responsibility has been embraced by the metals mining industry, and it’s being done right, she said. “So why do we have more conflict? Why are there more protests? Why does permitting take longer and longer?” Poulton made a case for an approach based on compatible, rather than sustainable, mining to present a new face of mining that can be compatible with communities, cultures and the environment, and still be profitable. When the mining industry starts to talk about compatibility between what it is doing and what “me,” as the consumer, wants, what “we,” as citizens of a community, want, and what’s good for the “world,” we’re going to see the next culture change happen, she concluded."

Jan 1, 2015

By F. B. Kuhnow

When performing blasting operations in open pit settings, energy is released and transmitted through the geology. Some negative effects can have significant impacts on mining operations and adversely affect mine production. This technical paper presents recommendations for blast design to prevent damage due to ground motion from blasting on adjacent concrete structures of underground operations. The paper includes a case study describing a problem regarding an open pit mine expansion and asks whether production blasting will damage concrete shaft structures due to blast stress waves and blastinduced ground motion. Based on the results, a set of criteria is provided to implement in current and future mining operations that involve blasting near underground concrete structures. A set of techniques on how to improve vibration levels for safe operations is also presented. Knowledge of particle velocity and wave propagation for site-specific circumstances to determine a safe level of vibration is recommended. Emphasis is placed on making use of electronic detonators and early delay detonators to achieve successful levels of vibration. A dynamic analysis is necessary to determine if vibration from blasting can damage the concrete shaft structure. When reinforced concrete structures are subject to blast loading, both concrete and steel are subject to very high strain rates. As opposed to static loads, when subject to high strain rate loads these materials increase their strength significantly. In fact, they increase by more than 50% for reinforcing steel, by more than 100% for concrete in compression, and by more than 600% for concrete in tension. This finding is of significant importance in mining operations because it allows an increase in flexural capacity of individual members as a result of high strain rates. Therefore, an elevated ground vibration (PPV) or particle velocity is permissible when blasting takes place near concrete structures.

Jan 1, 2014

By C. Stacy

The mining industry is changing rapidly. Competition among OEM and aftermarket vendors increases dramatically each year as a result of mergers and acquisitions, and especially technology advancements in the mining industry. Adding value to mine operations by delivering technical value and differentiation is becoming more subtle and more difficult to accomplish. Because of this, identifying and protecting intellectual property has become more important to the product development, engineering and marketing/sales continuum than it had been in the past. How companies protect intellectual property and determine the value of those assets is critical to the sustainability and differentiation of technology providers in the mining industry.

Jan 1, 2012

By T. F. Tomb

Although the number of operating longwalls (approximately 100) has remained relatively constant over the last five years, longwall production levels have significantly increased and have in some cases more than doubled. As a result of the increase in production, control of respirable dust continues to be a problem. Therefore, the Mine Safety and Health Administration (MSHA), Pittsburgh Health Technology Center, Dust Division, initiated a study to investigate the availability and adequacy of technology for controlling dust on longwall mining operations. The study involved 23 longwall mining operations in three different Coal Mine Safety and Health Districts. Each operation was visited for a full shift. Respirable dust samples were collected on face personnel and at fixed locations along the face. Parameters in place to control dust were noted with special emphasis being placed on obtaining quantitative data relative to ventilation, headgate dust controls, cutting drum sprays, external machine sprays and cutting sequence. Attempts were made to correlate dust control parameters in place at the time of the visit to dust concentrations measured at the tail, on the tail shearer operator and to the average concentration of dust determined from averaging all the measurements from the occupations sampled. The parameters in place to control dust were also compared to the gamut of technology known to be available to control dust. This paper presents a discussion on the effectiveness of the parameters in place to control dust and on the availability of technology for the control of dust on longwall mining operations.

Jan 1, 1990

By Rameshwar Sah, Somasekhar Pitchika, Akhil Singh, Seenivasan Rajiah, C. B. Dayanand, G. Balachandran

In the sintering of iron ores, the partial substitution of anthracite coal for coke breeze has been considered to be an effective way of reducing emissions and improvement in sintering properties. In the present study, the combustion characteristics of the anthracite coal and coke breeze were investigated and its influence on product sinter quality and sinter flue gases is being monitored. Pot trials are carried out with different coke breeze ratios, 0%, 40%, 50%, 60%, and 100%. It is found that as the percentage of anthracite coal is increased from 0 to 100%, the sintering time decreased from 24 to 20 min, and the productivity increased from 2.25 to 2.60 t/h/m2. Up to 60% anthracite coal substitution Tumbler index (+ 6.3 mm%), Product yield (+ 5 mm%), and fines generation (− 5 mm%) is found 62.29%, 85.17%, and 15.33%; moreover, hematite ( Fe2O3), magnetite ( Fe3O4), calcium ferrite phases ( CaFe2O4, CaFe3O5), and Silico ferrite of calcium and aluminum (SFCA) are major mineral phases found during microstructural analysis of product sinter. Keywords Sintering · Anthracite coal · Combustion rate · Productivity

Jun 2, 2022

By A. J. Basu

An overview of the evolution of computerized mine planning and design has been given, emphasizing the need for a knowledge-based system for planning and design of underground coal mines. An outline for the development methodology and procedure has been provided. Problem structuring guidelines have been used to incorporate intelligence and integration to the design modules. A skeletal model for a mine planning and design expert system has been prescribed, and the development process has been documented in detail. A feasibility prototype has been developed to test the structure of the skeletal model and to ensure completeness of the design process. The feasibility prototype development and its contribution toward proto typing has been addressed in this paper. At present, prototype development is underway. The prototype is expected to be avail-able for testing and implementation in early 1991.

Jan 1, 1991

By Neil and Associates

Seismic tomography is one of several additions to the suite of geotechnical engineering tools for use in various underground rock and mineral geologic structures. Seismic tomography is a method for reconstructing a cross section of an object based on attributes of seismic energy that have been transmitted through the object. The in-seam seismic tomogram provides a dataset that can be graphically portrayed in a color-coded format that is then used to infer relative stress concentration (Fig. 1). During the past several years, the US Bureau of Mines (USBM) at its Denver, CO and Twin Cities Research Centers in Minnesota funded several innovative hardware and software developments. These were directed toward use of in-seam seismic tomography for underground geologic strata evaluations. These preliminary investigations have matured into well-defined and field-proven technical advances for improving ground-control decision making in the mining industry.

Jan 1, 1996

By M. V. T. Da Silva, J. C. Harrison

Eldorado Gold Corporation of Vancouver, B.C. owns and operates three gold mines. The São Bento underground gold mine in Minas Gerais State, Brazil produced 105,907 ounces in1997. The La Colorada and La Trinidad open pit, heap leach mines in Mexico produced over 83,000ounces in 1997. With a deteriorating gold market plaguing the industry throughout 1997 Eldorado had to take critical measures at each mine to enhance gold production while lowering cash operating costs. Each mine had its own unique problems to confront. This case study will discuss three distinct courses of action taken at the three mine sites.

Jan 1, 1999

By Brian Zelenko, William H. Hansmire

"By the time the latest expansion of the Washington Metropolitan Area Transit Authority (WMATA) system, known locally as Metro and which opened in 1976, is completed in 2020, the system will serve 97 stations and operate on 188 km (117 miles) of track on six interconnecting lines. Metro provides a critical transportation link to a population of approximately six million people within a 3,900-km2 (1,500-sq-mile) Washington Metropolitan area and has allowed job growth to expand to all corners of the region. In the 1950s and 1960s, when the system was first conceived and construction began, most jobs were centered in downtown Washington, and most of the workforce commuted by bus or car. Today, transit-oriented development has increased residential, commercial and government facilities near most of the existing 91 stations increasing the importance of the Metro system as a critical transportation link for the region. According to recent American Public Transportation Association (APTA) data, Metro is the second busiest transit system in the United States (after New York City’s transit system).During the nearly 50 years of construction on the Washington Metro system, technology improvements and lessons learned from the global tunneling industry were implemented. Portions of this background and history have been adapted from other work by the authors Roach et al. (2017) and expanded for use herein. For soil tunnels, these improvements included the change from a “two-pass” tunnel lining with a typical initial lining of steel ribs with wood lagging or segmental precast lining erected within the tunnel shield followed by a final lining of cast-in-place concrete to a one-pass lining system of pre-cast concrete gasketed segmental lining. Soil tunnels were originally excavated using open-face tunnel shields, but changed over time. By the late 1980s, tunneling using closed, pressurizedface tunnel boring machines (TBMs) using a one-pass tunnel lining consisting of segmental precast concrete permitted tunneling in a wider range of soil conditions with much less risk of damaging overlying utilities or structures, greater safety for tunnel construction personnel and without the need to dewater the soils. However, due to concerns about conditioning clays with earth pressure balance (EPB) TBMs, open face machines were still favored by contractors for their better advance rates, lower cost and ability to deal with boulders that were occasionally encountered in the Coastal Plain Terrace Deposits."

Jan 6, 2018

By William C. York-Feirn, Jeffrey H. Kravitz, David Stalfort

"Mining is an inherently risky business. Over the years, major mine disasters have resulted in the deaths and injuries of thousands of miners in the United States. These disasters also resulted in innovations in approaches to mine design, operations and the training of miners and mine rescue teams. The U.S. Congress responded to these disasters with new laws designed to create mandatory safety and health standards as a means to eliminate fatal accidents; to reduce the frequency and severity of nonfatal accidents; to minimize health hazards and to promote improved safety and health conditions in the nation’s mines.Following a mine emergency preparedness and response holistic gap analysis in 2012, the U.S. Mine Safety and Health Administration (MSHA) identified the need for the development of risk and readiness assessment models for MSHA and the mining industry. MSHA’s objective was to evolve existing theoretical concepts for risk and readiness assessment into simplified tools that can be applied by the mining industry for use at operational levels. In 2012, MSHA hired ABS Group, a recognized industry leader in safety risk management and a wholly owned subsidiary of the American Bureau of Shipping, to develop self-assessment models to help meet this objective.In September 2012, MSHA chartered a project to supply the coal mining industry with a pro-active toolset for mine operators to:1. Self-assess the risks associated with underground coal mining operations in order to prevent major mine emergencies.2. Assess the preparedness of mine operators to respond to an emergency.3. Measure the readiness of mine rescue teams and responsible persons to execute emergency plans.MSHA’s objective was to evolve existing theoretical concepts for risk and readiness assessment into simplified tools that can be applied by the coal mining industry for use at operational levels."

Jan 10, 2018

By J. F. Hutwelker

A pilot plant was constructed and operated to investigate the column flotation of 20 x 200 mesh North Carolina phosphate ore, using high throughput, high solids operating conditions developed at the NCSU Minerals Research Laboratory. Flotation was performed at 45% solids in a 9.5 cm (3.75 in.) diameter by 2.26 m (7.4 ft.) tall column at throughputs of 19.1 t/hr/m2 (2.0 stph/ft2) and 31.7 t/hr/m2 (3.3 stph/ft2). Recoveries in excess of 98% of the phosphate value were obtained at the lower throughput -- while obtaining concentrate grades containing over 28% P205 (61.2% BPL) at that recovery. Recoveries of about 95% of the phosphate value were obtained at the higher throughput, while making a concentrate averaging 27.6% P209 (60.3% BPL). In addition, a better understanding of the variables governing the column flotation of coarse nonmetallic minerals was gained. Low air flow rates adversely affected concentrate grade at the lower throughput. At the higher throughput, phosphate recovery decreased at an elevated air flow rate. An unexpected result of the study was the effect that frother type had upon phosphate metallurgy. Use of Nottingham Econofroth 925 provided better flotation selectivity than American Cyanamid F-65 at the low throughput. This is significant since the high' throughput tests were conducted with F-65 exclusively. It is reasonable to expect further improvement in high throughput performance when the optimal frother type and dosage are determined.

Jan 1, 1993

By Adrian Molinari

A radioisotope probe (Minexan 202) capable of simultaneously analyzing a mineral slurry for five elements and pulp density has been developed by Outokumpu Oy, Finland. The probe is designed to operate immersed directly in a process stream, or it can be equipped with a flow cell through which passes a continuous sample of the main stream. A minicomputer (PDPII) is used to control the probes and calculate the assay data. This paper describes the probe as applied to slurry analysis and compares it to the conventional x-ray on-stream analyzer (Courier 300).

Jan 1, 1977

By T. W. Camm

Aristotle made the observation that man is a political animal. Engineers often like to think they are above the fray when it comes to organizational politics, but most organizational theorists believe politics is a fundamental dynamic in any group. This paper examines the various ways that people use power within organizations to negotiate the political interactions in the work place.

Feb 27, 2013

By Joseph A. Dos Santos

The largest TBM (Tunnel Boring Machine) tunnels are typically along modest slopes, but not always. Occasionally high slope angles are required beyond the capabilities of conventional open trough trailing conveyors. A 2019 project required a large TBM to ascend to an incline angle of 25°. A Sandwich Belt high angle conveyor could easily solve the high angle conveying problem but such a system must include all of the features of the conventional trailing conveyor, particularly the ability to extend with the TBM advance. The writer responded to the challenge and developed a TBM trailing Sandwich Belt high angle conveyor with all of the needed features. The invention (U.S.A. patents awarded October, 2021 and November, 2022) however goes beyond the 2019 project requirements and extends to any high angle incline. This writing first presents the broad Sandwich Belt high angle conveyor development, then its use in various construction and tunneling projects prior to this TBM Sandwich Belt trailing conveyor invention. Finally we present the new TBM Trailing Sandwich Belt high angle conveyor with all of its features and implications.

Jun 13, 2023

By L. J. Buter, D. J. Collins

Introduction FMC's Paradise Peak gold mine was discovered by staff geologists in July 1983. Located south of Gabbs, in western Nevada, the deposit contains about 11 Mt (12 million st) of ore grading at 3.6 g/t (0.105 oz per st) of gold and 129 g/t (3.75 oz per st) silver. It is estimated that the ore contains 34 t (1.1 million oz) of recoverable gold and 933 t (30 million oz) of recoverable silver. The 3.6 kt/d (4000 stpd) mill began operation April 14, 1986, just 18 months after Davy McKee completed a feasibility study and construction, and two-and-a-months ahead of schedule. It also came in about 10% under budget at a cost of about $100 million. Crushing Run-of-mine ore is delivered from the mine in 45-t (50-st) haul trucks to a 272-kt (300,000-st) capacity open air stockpile. Ore is reclaimed using 5 m3 (7 cu yd) front-end loaders that feed a 91-t (100-st) hopper equipped with a 610- x 610-mm (24- x 24-in.) grizzly. A 1.4- x 11-m (54-in. x 35-ft) apron feeder delivers ore from the hopper by way of a vibrating grizzly screen with 127 mm (5 in.) openings to a 1- x 1.3-m (43- x 51-in.) Rexnord jaw crusher. Crushed material is conveyed to a 1.8- x 4-m (6- x 14-ft) Link Belt vibrating screen equipped with a 50-mm (2-in.) manganese grizzly bar deck. Screen oversize is fed to a 1.7/0.6-m (5.5 ft) Rexnord standard cone crusher. Product from this crusher joins the -50 mm (-2 in.) screen undersize and is conveyed to a 136-t (150-st) surge bin. Three hydraulically driven belt feeders deliver ore from the ore bin to three 2 x 6 m (7 x 20 ft) Link Belt single-deck tertiary screens fitted with 6 x 25 mm (0.25 x 1 in.) slotted polyethylene screens. Screen undersize - -6 mm (-0.25 in.) rock - is conveyed to a 3.6-kt (4000-st) ore storage bin. Screen oversize is delivered by way of a conveyor to a 91-t (100-st) surge bin. From this bin, two belt feeders feed ore to two 1.7 m (66 in.) Rexnord Gyradisc crushers, which are in closed circuit with the tertiary screens. Design features include magnetic protection for tramp iron removal and sloping floors and pump sumps for ease of clean up. Dust scrubbers keep the working environment clean and in compliance with state dust emission regulations. Grinding Two 1 x 4.5 m (3.5 x 15 ft) belt feeders deliver ore from the fine ore bin to a conveyor belt that feeds it to the 5 x 7 m (16 x 22 ft) Allis-Chalmers ball mill. The conveyor belt is equipped with a Merrick weightometer. This controls feed rate to the ball mill by speed control on the hydraulic motors driving the feeders. The 2.6 MW (3500 hp) powered mill grinds 3.6 kt/a (4000 stpd) to an average grind of 85% -75 µm (-200 mesh). The mill is in closed circuit with four 660 mm (26 in.) Krebs cyclones. Three of these are normally in operation while one is a standby. Warman pumps feed the cyclones through a cyclone distribution manifold. The cyclone underflow returns to the ball mill, which has a 300% average circulating load. Mill discharge pH is 11, and that is obtained through pebble lime addition to the feed belt. Cyclone overflow is sampled using a Heath & Sherwood two-stage sampler. It then flows to a 27-m-diam (90-ft-diam) Eimco thickener. Thickener overflow is returned to the grinding circuit, while underflow at 50% solids is pumped to the leaching circuit. Grinding-circuit design features include a steeply sloped floor for ease of clean up, an open area over the pumps for maintenance accessibility, and a ball hopper with a self discharge bottom to speed ball addition. Other features include a mill liner handler and an air clutch that connects the mill motor to the mill.

Jan 12, 1986

By L. K. Bandyopadhyay, P. K. Mishra, S. K. Chaulya, R. S. Singh, A. Kumar, N. Tripathi, K. Mandal

A comprehensive field study has been carried out to measure the background air quality status and identify the air pollution sources from opencast mines around a heritage site in India. Air quality modeling has been carried out to envisage dust concentration due to the existing and closed mines in the region. The predicted total PM10 and PM2.5 levels at the selected receptor locations ranged from 86.39 to 194.89 and from 34.82 to 99.55 µg/m³, respectively.

Jan 12, 2022