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By Paul B. Queneau, Barry J. Hansen, D. Erik Spiller

Most lead and zinc secondaries are recycled pyrometallurgically. However, many problems encountered in secondary smelters have been solved by addition of physical concentration and/or hydrometallurgical processing steps, with resulting important environmental benefits. U.S. secondary lead and zinc operations are described, covering conventional smelters, EAF-dust treaters, and zinc sulfate/fertilizer producers, including plant capacities, technologies, and outputs. During the past two decades, remarkable advances have been achieved by recycling spent lead-acid battery components. Interaction between primary and secondary zinc producers, the fertilizer industry, and the zinc chemical industry has substantially decreased waste generation.

Jan 1, 1993

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 Gordon Clark, Basar Arioglu, Nasri Munfah, Sanja Zlatanic, Tolga Togan

"The 13.2 m (43 ft) external diameter, double deck Istanbul Strait Road Tube Crossing is one of the most challenging underwater tunnel projects in the world. Subjected to 11 bars of hydrostatic pressure, variable geology, and being in a very active seismic area, the execution of the project required innovative solutions, sophisticated construction techniques and prudent risk management approach. The 5 km (3.1 mile) tunnel consists of a 3.4-km (2.2-mile) tunnel boring machine- (TBM) bored tunnel, 1 km (0.62 mile) twin NATM tunnels and cut-and-cover sections. The project is being delivered in a build-operate-transfer (BOT) contract in a public-private partnership. The technical challenges, coupled with financial and commercial risks required the implementation of sophisticated risk management tactics including the provision of independent design verification. The project was opened to traffic on December 20, 2016, four months ahead of schedule.. This article presents the technical challenges of the project from the design, construction, and risk management aspects..Project backgroundThe $1.245 billion Istanbul Strait Road Tunnel Crossing project, dubbed the Eurasia Tunnel, is one of several major infrastructure projects being implemented in the Republic of Turkey in a public-private partnership approach. The project provides a direct and easy connection between the Anatolian (Asian) side of Istanbul and the heart of its historical district on the European side across the Bosphorus Strait which connects the Black Sea with the Sea of Marmara. The project improves connections to a wide network of motorways on both sides, increase capacity across the Bosphorus by 100,000 vehicles a day, reduces congestion and saves motorists an average of 45 minutes of commuting time in each direction bringing significant economic benefits to the city and the region. It eases traffic across the strait, reduces congestion, decreases pollutants and emission while maintaining Bosphorus. It is the most complex part of the project with the greatest challenges and risks. Part 2 is 5.4 km (3.6 miles) long consisting of 3.4 km (2.2 miles) of 13.2 m ( 43.3 ft) external diameter TBM bored tunnel under the Bosphorus Strait, 1-km (0.62-miles) of twin NATM tunnels on the Asian side, cut-and-cover transition boxes in the Asian and the European sides and depressed approaches on both sides. In addition, this segment includes the toll plazas, ventilation buildings, and the tunnel control and maintenance facilities."

Mar 1, 2017

By Angelus S. C. Owili-Eger

The protection of groundwater resources is a growing issue on both the legislative front and within the private sector. At present, the legislative push is to establish within the Environmental Protection Agency a comprehensive research, development, and demonstration program relating to groundwater contamination and resources. It is evident that certain aspects of such legislation will be directed at the mining industry. Consequently, the mining industry must position itself to address the issues and concerns from a backdrop of facts and knowledge by developing an integrated hydrogeochemical model of the mining environment.

Jan 1, 1989

By Marc Carriere

Bright-orange couplings adorning piping systems are a common sight in just about every underground mine in North America. Grooved mechanical piping, the pipe-joining system that utilizes these couplings, is the preferred method for joining underground and plant piping systems in the mining industry, due to the ease and speed of installation and maintenance. However, the applications for such systems have traditionally excluded high-pressure systems. Most grooved mechanical couplings have a moderate working-pressure limitation, so high-pressure systems have required the use of alternative joining methods, typically heavy-duty flanges. However, the introduction of high-pressure couplings (up to 4,000 psi) has made the grooved joining method viable, and even preferable, for backfill, deep-mine chilled water and dewatering lines and other high-pressure piping applications. As engineers explore the use of high-pressure couplings, questions will undoubtedly arise about the joining method?s capabilities. This article will address the capabilities and specifications of high-pressure couplings, and compare flanged and grooved mechanical pipe joining in traditional as well as high-pressure underground mining applications.

Jan 1, 2011

By L. T. Larson

Nothing in Turkey is simple. Its his¬tory is long and convoluted, its culture fascinating, its metallogeny diverse, and its geology very complex. This article will focus on the geology of western Anatolia and the precious metals poten¬tial of this third of Turkey. Any gold produced by mines in Tur¬key since the early 1900s has been a by-product of the mining for other met¬als, such as copper from the massive sulfide deposits of the Pontics. Archaeological records, however, prove that gold was mined from the Pactolus (present day Gediz) River and refined by Croesus at Sardis in about 550 BC. Other records and legends make it possible that gold was mined before 1200 BC for the Homeric City of Troy (Priams treasure?) about 25 km (15 miles) east of Canakkale at Mad¬endag and Kartaldag. A final legend of antiquity suggesting gold in what is now Turkey relates to King Midas. And, indeed, the city-state belonging to a king of that name has been recognized near the city of Eskise¬hir. More recently, precious metals have been mined at Madendag-Kartaldag in the late 1800s. Arapdag, near Izmir, remains the only "authenticated" epith¬ermal precious metal deposit in Turkey (Mosier et al., 1985). With this spotty record, why the sud¬den interest shown by at least five Euro¬pean-based, three or four US-based, and several other international mining firms and their Turkish subsidiaries? Like other aspects of Turkey, the complete answer is not simple but, reduced to its basics, has three parts. Turkey, relative to many developing nations, has a stable, democratic form of government (although it also has a for¬midable bureaucracy) whose currency exchange rate is premised on the US dollar. New laws promulgated since 1983 have opened the country and welcomed foreign investment. Some have even provided investment incentives. The Mining Law of August 1985 made sweeping reforms of the old land tenure system. This law made it possible for a foreign-based company to have a wholly-owned Turkish subsidiary en¬gaged in mining. Equally important is the belated recognition that western Anatolia, while geologically compli¬cated, is today basically a province Neogene extensional tectonics having many of the geologic attributes of the leading gold producing province of the US - the Basin and the Range. Geologic rationale for precious metals exploration Tectonic/lithologic framework: Alle¬gorically and simplistically, Anatolia during early Neogene (middle Miocene) can be likened to a tube of toothpaste with the cap off. It is squeezed in the vise formed by the Arabian plate mi¬grating north toward the southwest end of a stable Asian platform. The "tube" was compressed. It could not expand to the east because it was sealed by what is now southern Russia and Iran. The filling of the tube escaped to the west, in the direction in which the cap was miss¬ing (Fig. 1). So developed during the middle to late Miocene the western-most struc¬tural province of Anatolia. This was done by a process aptly termed tectonic "escape" by Sengor et al (1985). This province is dominated by exten¬sional tectonics much like the Basin and Range of the western US and has an estimated extension of between 30% and 50%. The most striking manifesta¬tion of this extension is the 10 to 11 major east-west trending grabens (Ge¬diz, Buyuk Mendares, Kocuk Mendares, etc.) and intervening horsts, although a much greater number of smaller, gener¬ally northeast-striking grabens and half

Jan 1, 1989

By Robert L. Bates

An industrial mineral, says the Glossary of Geology, is "any rock, mineral, or other naturally occurring substance of economic value, exclusive of metallic ores, mineral fuels, and gemstones; one of the nonmetallics." Probably most geologists and engineers would accept this simple and straightforward definition, at least as a general statement. On analysis, however, certain anomalies crop up. For example, what is metallic and what is nonmetallic? Bauxite and ilmenite certainly qualify as metallic ores, but both are also raw materials of important nonmetallic substances; hence they are included in this book. Another anomaly is that, by common consent, the term industrial minerals may include not only rocks and minerals but also certain manufactured products, such as cement and lime, and even mixed groups of natural and artificial products, such as abrasives and refractories. Thus the central realm of the industrial minerals is clear enough, but its boundaries tend to be indefinable. Since a definition that allowed for every irregularity in the outer fringes would be excessively unwieldy, the one quoted above may be considered satisfactory. The expression industrial minerals is commonly equated with nonmetallics, and with the somewhat more precise phrase industrial minerals and rocks as in the title of this book.

Jan 1, 1994

By R. A. Jankowski

The US Bureau of Mines (USBM) conducted a series of laboratory tests to investigate the effectiveness of using a flooded-bed scrubber with exhaust ventilation in deep-cut faces. An experimental test program to determine the impact on respirable dust levels resulting from changes in face airflow, curtain-setback distance, operator positioning and operating parameters of the external spray system on the miner was completed. Gravimetric sampling was conducted in the immediate return and at three sampling locations on the off-curtain side of the entry. Statistically significant differences in dust levels, on the order of 0.5 to 1.2 mg/m3, were observed between specific sampling locations and changes in several test parameters. Dust sampling results indicated that a flooded-bed scrubber and exhaust ventilation can be a viable dust-control system for extracting deep cuts up to 12.2 m (40 ft) in length. The impact on methane was not evaluated.

Jan 1, 1998

By D. H. McCain

Through a unique partnership between the Colorado Mine Safety and Training Program (CMSTP), the Colorado Rock Products Association (CRPA) and the Higher Education and Advanced Technology (HEAT) Center, a video packed, dazzling CD-ROM training program was developed for new miners entering the aggregate industry. Why this product was developed, and why the aggregate industry, will be discussed along with the challenges faced throughout the project. Cooperation from every one involved including MSHA made this the product of which all other training materials in the mining industry will be measured against in the 21st Century. This product's versatility and wide application makes it a tool that is as critical to a mine's success as any earth moving machine. Developed with both state and federal grant moneys allows this product to be affordable to small operators and independent contractors. The quality of this two CD-ROM set rivals any commercially made CD-ROM training.

Jan 1, 2001

By Louis M. Schlesinger, Michael J. Garska, Joel F. Hutwelker, James T. Jr. Tanner

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% P205 (60.3% BPL). In addition, a better understanding of the variables governing the column flotation of coarse nonmetallic minerals was gained. Variables examined included superficial air velocity, throughput (superficial feed velocity), frother type, frother dosage, and bias rate.

Jan 1, 1993

By P. T. Luckie

More efficient classification with a single hydrocyclone through equipment and/or operating design changes does not appear possible. However, improvement in classification efficiency by increasing the sharpness index and decreasing the apparent by-passing while changing the cut size is possible through proper staging of inefficient hydrocyclones. But feasible multistaging requires achieving the necessary material balances around the units. Because of the interactions among the units, these balances require extensive iterations. The final step before commerical installation should be a laboratory demonstration, in order to define the control algorithm required to maintain stability. However, eventually a sufficient knowledge base should be developed that will permit simulation in place of laboratory testing as well as the incorporation of a feed forward strategy.

Jan 1, 1989

By C. L. Jiang

The selective depression of pyrite obtained from Kentucky No.9 seam in coal flotation with various kinds of inorganic and organic chemicals was systematically examined. Most of the organic chemicals tested showed little selectivity in pyrite depression. It was found that both orthophosphate and pyrophosphate were effective for the selective depression of coal pyrite in coal flotation using fuel oil as a collector. At substantially low concentrations of pyrophosphate, the flotation of coal pyrite was completely depressed over a wide pH range, while the coal flotation remained unaffected. The mechanism of the selective depression of pyrite by phosphates has been explained with the help of thermodynamic calculations of iron-phosphate-water systems and zeta potential measurements. It was shown that pyrophosphate reacts strongly with iron ions of pyrite to form stable hydrophilic iron pyrophosphate complexes on pyrite surfaces.

Jan 1, 1998

By Paloma Lazaro, Moe Momayez

Heat-related illnesses (HRI) are relatively common in both hot surface and underground mining operations. When workers are exposed to extreme heat or strenuous work in a hot environment, they become prone to heat stress. Heat strain is the result of the body’s response to external and internal heat stress. It is therefore vital for the conditions leading to heat strain be detected and treated in a timely manner. Heat-related illnesses are manifested by exhaustion and heat stroke. The predicted heat strain (PHS) [ISO 7933 (2004)] model has been developed to predict the health condition of the worker in terms of core body temperature and water loss. The PHS model tested in this study is based on eight physical parameters that are measured at different intervals during a work shift. They include air temperature, humidity, radiation, air velocity, metabolic rate, clothing insulation, posture, and acclimatization. The model predictions are then compared with a direct physiological measurement, such as core body temperature. We present the results of an extensive study that monitored and predicted body’s response to heat stress under different environmental and working conditions. The PHS model provided reliable results in most instances in comparison with other prediction methods currently in use in the field.

The 20th annual American Mining Hall of Fame Awards Banquet sponsored by the Mining Foundation of the Southwest will be held at the Westin La Paloma in Tucson, AZ, on Saturday, Dec. 7, 2002. This year’s inductee, guest of honor and featured speaker is J. David Lowell, one of the preeminent exploration geologists of the past 30 years. Among his most recent discoveries is the world-class Pierina gold deposit in Peru, currently owned and operated by Barrick Gold. As representatives of mining heritage, the Hall of Fame will induct Howard Allen Twitty, Sr., and Bernhardt Rohe. Twitty was a respected public lands attorney. He made significant contributions to the mining industry by representing several major companies in many court cases. He was also the author of numerous papers on mining law. Rohe was managing director of Peñoles. In that position, he helped guide the Mexican mining company for its growth into the international mining company that it is today.

Jan 1, 2002

By William Petruk

Performance assessments are carried out to monitor operations, to evaluate performance and to identify processing problems. The assessment involves collecting and analyzing representative samples from critical points in a flowsheet and interpreting the data. Sample analysis techniques include chemical analyses, mineralogical investigations, mineralogical analyses, and materials balancing. Chemical analyses provide the lowest cost assessment and should be used liberally, particularly in monitoring a process. Materials balances performed on chemical assays for a suite of samples are used as a first step in evaluating a process. Mineralogical investigations are more expensive than chemical analyses but need to be used only at the beginning of mining and metallurgical operations and as a second step in assessing processing problems. Quantitative mineralogical analyses combined with materials balancing provide the most complete performance assessment, but the procedure is expensive. On the other hand, the assessment has the potential of a large payback when carried out where warranted.

Jan 1, 1991

By Harold D. Palmer

The marine geologist and coastal engineer have at their disposal a wide variety of geophysical tools with which to investi¬gate sea floor topography and structure. Such devices include towed magnetometers, shipboard gravimeters and a variety of acoustical systems for recording the relief of the sea floor and buried structural features. The versatility of this latter group of systems lends itself to a variety of applications essential to those projects where excava¬tion of the sea floor is required. This paper describes the use of several acoustic devices and their Limitations and presents a case history in which a rapid survey from a small vessel provided detailed information critical to the planning stage of a specific coastal project. In this discussion, shallow water is defined as depths less than 150 feet. At present, this limit includes the maximum depth of economic dredging and most other offshore activities. To be sure, the maximum depth at which routine useful work can be accomplished is rapidly increasing, but the majority of current marine activities are located in water depths here defined as shallow.

Jan 1, 1968

The sixth annual conference of the Mineral Economics and Management Society (MEMS) was held Feb. 27 through March 1 in Boulder, CO. This year's event was attended by more than 100 academic, industrial, government and other professionals interested in mineral economics and materials management. With about 250 members worldwide, this not-for-profit society seeks to promote scientific and economic analysis of current relevant issues. This year's program was sponsored by Alcan, Bateman Engineering, Cyprus Amax Minerals, J.P Morgan, Knight Piesold LLC and Newmont Gold. The conference's technical program consisted of six sessions. These included "Financial tools for a changing world," "Access to minerals," "Comparing North and South America," "Environmental issues in today's world" and "Transporting minerals." The program was concluded with a panel discussion titled "National minerals policies in Asia." In addition, a student papers session was held, in which students were given the opportunity to compete for a $1,000 award. The following is a brief review of the technical pro¬gram.

Jan 1, 1997

By D. B. Sikka, R. B. Bhappu

Porphyry-type copper-molybdenum (Cu-Mo) deposits typically occur in the Phanerozoic rocks and have been well-documented. During the past two decades, a number of porphyry-type Cu-Mo deposits that range in age from 1055 Ma to 2970 Ma have been identified in the Precambrian rocks of Australia, Canada, China, Finland, India. Namibia and Zambia. The Malanjkhand porphyry copper deposit M.P., India is estimated to contain 789 Mt (870 million st) averaging 0.83% copper (mill headgrade); 0.004% molybdenum; 0.2 g/t (0.006 oz/st) gold; 6 g/t (0.175 oz/st) silver and a cap of 7.5 Mt (8.2 million st) of oxide ore averaging 0.8% copper. The economic potential of the expanded copper mining milling, smelting and refining complex is expected to yield cathode copper 118.6 kt (130,700 st); molybdic oxide 830 t (914 st); gold 1.9 t (61,732 oz); silver 46.6 t (1.5 million oz); sulfuric acid 240 kt (264,500 st), copper from leach dumps 11.5 kt (12,600 st); nickel 24 t (26,400 st); cobalt 84 t (92,600 st); bismuth 16 t (17.6 st); selenium 48 t (53 st), tellurium 4.8 t (5.3 st).

Jan 1, 1995

By John E. Urosek, Herman Schade

In March, 1988, a fire occurred in a large underground coal mine. Coal Mine Safety and Health of the Mine Safety and Health Administration was immediately notified of the situation. They requested the assistance of the Pittsburgh Health Technology Center (PHTC) to provide monitoring and analysis of the mine atmosphere in and around the fire area to insure the safety of the miners escaping from the mine and for the miners involved in extinguishing the fire. The capability to provide this type assistance is maintained by the PHTC Offices located at 4800 Forbes Avenue, Pittsburgh, Pennsylvania. The equipment used is maintained field ready and can be mobilized almost immediately. This paper will discuss the response to this recent major mine fire.

Jan 1, 1989

By N. Aouad

The deployment of large machinery for low cost, bulk surface mine production operations has resulted in high-impact shovel loading operations (HISLO). In extreme cases, shovels load large dump trucks with 100-ton (or more) passes generating high-impact forces under gravity. HISLO generates high-frequency shockwaves that cause severe truck vibrations exposing operators to whole body vibrations (WBV). Current research study in this area has established that the vibration levels affecting the operator?s seat, lower-back, lumbar and cervical regions fall within the extremely uncomfortable zone compared to the ISO 2631 comfort zone. These results pose health threats to truck operators over long-term exposure to these vibrations. In this paper, the authors will examine engineered solutions to mitigate these health threats.

Jan 1, 2011