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By Peter Krag, Rob Henson

It is well known that titanium and zirconium alloys offer superior corrosion resistance in the oxidizing sulfuric acid environments present in sulfide pressure leaching operations. The use of these materials is limited, however, due to their pyrophoricity; several accidents attributed to titanium equipment have been described in technical literature, and other, minor incidents·occur regularly1 • We describe an application of a commercial titanium alloy, Nb-55 Ti, with suitable mechanical properties, corrosion resistance similar to Grade 2 Ti, and featuring a significantly reduced field of ignition conditions

Jan 1, 1992

By J. Eldridge, A. J. Carter, D. N. Leavell

Minpro International has developed an innovative, flexible¬shaft impact crusher that produces glass aggregate from mixed¬color, post-consumer glass. The crusher operates with low power and generates a subangular aggregate, with minimal fines. Output is screened to yield sized aggregate, which can be used directly as surfacing material in Owens Corning's shingle process. Metal, plastic and paper waste is preferentially removed by the Minpro system. Duval County and the City of Jacksonville collect more than 12,000 tons of glass bottle waste per year. It is anticipated that a successful end-use application by Owens Corning, will allow increased collection and cost-effective glass recycling in north Florida.

Jan 1, 2002

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 George McArthur

GEOLOGY One of the largest copper resources in North America occurs in the Bingham mining district, located 40 km (25 miles) southwest of Salt Lake City, UT. Anaconda's present contribution to the development of this resource is the Carr Fork mine. (Fig. 1, Bingham district plan map.) The Carr Fork story began about 300 million years ago when a thick sequence of sedimentary quartzite and limestone was deposited in the Oquirrh Basin. Subsequent earth stresses formed a series of west-northwest-trending overturned anticlines and synclines that were later offset by northwest-striking thrust faults and northeast-trending normal faults. (Fig. 2, Bingham district cross section.) About 38 million years ago the Bingham stock was intruded into some of the folds, resulting in the formation of porphyry ore in the intrusive, and fissure, replacement, and skarn ore deposits in the sediments. The Carr Fork skarns were formed preferentially in two limestone units, called the Yampa and Highland Boy, which average about 46 m (150 ft) in thickness, separated by about 76 m (250 ft) of quartzite. Copper mineralization consists almost entirely of chalcopyrite associated with pyrite and molybdenite in a gangue of garnet, diopside, magnetite, quartz, and carbonate. Molybdenum, gold, and silver are economic byproducts. (Figs. 3 and 4, indicated ore in plan and section.) EXPLORATION HISTORY The West Mountain mining district, of which Carr Fork is a part, was organized in 1863, after leaf-silver ore was discovered in the Carr Fork of Bingham Canyon. However, it was not until 1873, when the Bingham and Camp Floyd railroad to the town of Bingham was completed, that the mining camp flourished. Many small mining companies in the district were reduced, often through consolidation. By 1937 only the National Tunnel and Mines Co. was active in the Carr Fork area. In 1948 it declared bankruptcy, and was later purchased by The Anaconda Co. Anaconda conducted geologic investigations in the Bingham district until 1968, when a concerted diamond drilling program was initiated to fully evaluate the geologic potential of the Carr Fork area. The exploration program commenced with one diamond drill, but was enlarged to three drills following discovery of the first major ore intercept. Near completion of the exploration effort, large oil well rotary drills were used to drill to depths of 762 to 914 m (2500 to 3000 ft), after which the holes were completed by standard diamond drilling techniques. All holes were collared vertically, but considerable deviation occurred because of structure and rock conditions. Wedging and directional drilling were used to keep the holes on target and to provide multiple ore intercepts in the deeper holes. Geophysical surveys, in-

Jan 1, 1982

By J. E. Lees

Advanced remote sensing can be a powerful new information tool to help private and public entities make better environmental and resource management decisions. However, some regulated entities are reluctant to develop or use this tool because of their concerns that it will lead to increased risks and costs of environmental legal liability. They fear that new ways of monitoring the environment will increase liability, undermine existing enforcement agreements, reopen compliance agreements, and generally provide a competitive disadvantage to early adopters by accelerating environmental cleanup costs. Others counter that the increased risks are marginal, and that several advantages outweigh these risks, including the opportunity to more effectively manage environmental operations, target and set priorities, measure and track management and compliance effectiveness, provide more defensible environmental assessments and baseline conditions, make and defend optimal siting decisions, and avoid or resolve environmental disputes. This paper offers strategic advice on ways regulated entities can enjoy the benefits of these powerful new information tools while mitigating down-side legal and compliance risks as much as possible.

Jan 1, 1999

By Pengfei Wang, Guorui Feng

"With the depletion of easily minable coal seams, less favorable reserves under adverse conditions have to be mined out to meet the market demand. Due to several historical reasons, a large amount of remnant coal was left unrecovered. One such case history occurs with the remnant rectangular stripe coal pillars using partial extraction method at Guandi Coal Mine, Shanxi Province, China. The challenge that the coal mine is facing is that there is an ultra-close coal seam right under it, with an only 0.8 to 1.5 m sandstone dirt band in between the two. The simulation study was carried out to investigate the simultaneous recovery of upper remnant coal pillars while mining the ultra-close lower panel using longwall top coal caving (LTCC). The remnant coal pillar was induced to cave in as top coal in LTCC system. Physical modelling shows that the coal pillars are the abutments of the stress arch structure formed within the overburden strata. The stability of overhanging roof strata highly depends on the stability of the remnant coal pillars. The gob development (roof strata cave-in) is intermittent with the cave-in of these coal pillars and the sandstone dirt band. FLAC3D numerical modelling shows that the multiple seam interaction has a significant influence on mining-induced stress environment for mining of lower panel. The pattern of the stress evolution on the coal pillars with the advance of the lower working face was found. This demonstrates that the stress relief of a remnant coal pillar enhances the caveability of the pillars and sandstone dirt band below them.INTRODUCTIONChina is one of the world’s coal-rich countries. Coal has played a significant role in the growth of China’s economy. Coal reserves have been mined commercially in China for over one hundred years. The demand for coal in China is still going to grow at a relatively high rate (BP Energy Outlook, 2019). Long-term large-scale and intensive coal mining activities have created tension between increased demand and limited resources (Bai et al., 2018). Easily minable coal seams such as sub-horizontal, tabular, and laterally extensive coal seams are being depleted, and therefore the remaining reserves are becoming less favorable. However, in many situations, the coal reserves under adverse conditions have to be mined out to meet the market demand for energy.Due to sedimentary environments and geological conditions, many coal seams are interspersed with sedimentary bands, or partings both within an individual seam and between seams. These bands and partings lead to appearance of ultra-close coal seams, as well as giving rise to considerable variation in their structural and mechanical properties (Ghabraie and Ren, 2016). Difficulties are encountered in the mining of such coal seams. If ultra-close coal seams are mined sequentially, that requires the design of a mining system for each individual coal seam; also, a large number of gateroads have to be excavated, which is not a high-efficiency option. If ultra-close coal seams are mined at a great mining height at once, for instance, using longwall top coal caving—a longwall mining method that is widely used in China for the mining of ultra-thick coal seams—then the location and characteristics of the band would have a significant influence on success of their extraction."

Jan 1, 2019

By Vi-Duong Dang

Lithium requirements in the next few decades for batteries and controlled thermonuclear fusion reactors (CTR) may exceed the availability of the current mineral and brine reserves. It is thus prudent to search for new reserves and resources to satisfy these and future lithium applications. The lithium content of the waters from the Smackover oil field. located in the Gulf Coast region of the United States, ranges from 100 to 500 mp/l and could represent a substantial new reserve. Experimental evidence described in the literature indicates that a specific chelating agent dipivaloylmethane (DPM), of the diketone type, has a specific selectivity toward lithium in the presence of other metal ions in aqueous solutions. Based in part on this unique property of dipivaloylmethane, a conceptual design of a full-size plant to extract lithium from the Smackover brine is presented in this paper. This study includes alternate flow-sheet development, design information on the major units of the process, energy requirements, and an economic analysis of a facility capable of producing 106 kg of lithium per year. The economics of three different process concepts depend primarily on the amount of water needing to be evaporated from the initial oil-field feed waters in concentrating the brine. The results, as a function of production rates, are indicated only in a general manner.

Jan 1, 1978

By John Clarke Holman

Industrial growth and survival in today's competitive world means both economic efficiency and technological superiority. Superior technology includes not only exploiting the best methodologies and techniques presently available, but also a continuous search for and development of, better ones. In practical terms this translates into an investment of substantial sums of money. Of course, even a relatively small investment will not be justified if the fruits of the project cannot be secured to the investor and the inventor alike. There are at least three ways to protect new or improved technology. If the improvement reaches the height of an invention, "patenting" usually is the preferred mode of protection. If, however, the improvement is novel and valuable but does not satisfy the requirements of the patent laws, one may then consider "trade secret" agreements as a means of obtaining appropriate return for the investment made so long as the improvement is capable of being maintained in secret and cannot be "reverse engineered." If one develops a new and useful organism and seeks immediate protection from infringers, current thinking is that the copyright law may afford such protection simply by publishing the genetic code. Here is one instance where you may publish without perishing! This paper will endeavor to highlight the pros and cons of various legal mechanisms and their applicability to the frontiers of technology.

Jan 1, 1985

By Lawrence R. Molsather

Certain hydrologic parameters are affected by development of a mine. These include the area, yield, and storage in a watershed. Alteration of these parameters results in variations in lake levels and stream flow rates and in changes in ground water elevations and gradients. These factors have become increasingly important in light of present environmental design standards and government regulations. Mitigation of adverse hydrologic impacts can be costly and can create operating constraints which complicate the mining process.

Jan 1, 1980

By A. English, Edward Martinez, L. A. Haas, N. W. Johnson, Harrison Copper, M. E. Tawil, C. C. Harris, G. V. Jergensen, D. Halbe, M. P. Amsden

Declining US ore grades along with skyrocketing energy, materials, labor, and regulatory costs underscored the urgency for technological innovation in the mineral processing area. Re¬liance on the scale-up and automation of unit operations was the sector's primary battle plan. Debate continues on the upper size limit of concentrating plants and whether process controls should be centralized or distributed in the mill. In the materials handling area, the economics of large-scale and mobile systems, particularly conveyors, were well documented in the literature. Comminution, the most costly and energy consuming area of the processing flowsheet, saw improvements in process controls and liner designs. The trend toward larger grinding units stalled somewhat during the year owing to some operational problems at commercial plants. Research and development of apparently less expensive physical separation processes-that also boast recovery of cleaner and more environmentally acceptable products -gained momentum during the year. Because of escalating capital cost requirements for new plant capacity, the year saw a greater interest by mill designers to re-examine existing capacity. The focus here is clearly to modify or retrofit unit operations with more efficient components as an alternative to installing more costly new equipment. The problems facing the processing sector during the 1970s can be expected to continue in the decade ahead. Technological gains from scale-up and process controls appear

Jan 5, 1980

By P. N. Bradbury

The coal companies of today have to make all of their in-the-field managers MAINTENANCE PRODUCTION MANAGERS. By using a computer application to monitor all aspects of the daily production as well as the maintenance, a company can immediately effect a cost reduction by studying the down-time and delay trends on an everyday basis. This paper will outline how a company can use a program to not only put a stop to the increasing supply and maintenance costs but start trimming each of these cost centers while actually increasing the efficiency and productivity of the current work force.

Jan 1, 1991

By T. Knuutinen, M. Klemetti, P. Mörsky

This paper presents a comparison study done at VTT's new pilot plant facilities in Outokumpu, Finland, for chromite ore. The ore was ground in a rod mill -, a ball mill - and high pressure roller mill - ball mill circuit in the capacity range of 0.5 - 3.0 t / h. The main grinding characteristics are discussed and the quality of the products are compared from the mineralogical point of view. The benefits of high pressure roller mill comminution for further mineral processing of chromite is also discussed.

Jan 1, 1995

By L. L. Lien

In this economic age of high interest rates and softening mineral commodity markets, the mining industry is taking a hard look at how it conducts its business and where economies can be effected. The capital investment to build a new metallurgical facility or open a new property has traditionally attracted substantial investigation, analysis and management attention. The areas of mineral exploitation, financial feasibility, engineering and construction have been studied extensively and their management, although still difficult, have become refined disciplines.

Jan 1, 1982

By R. Ramesh

Understanding the nature of coal surface heterogeneity is a prerequisite to accurate characterization and efficient control of coal surfaces. New techniques based on the centrifugal immersion of particles from the liquid/ vapor interface and film flotation have led to independent estimation of surface energy distributions in individual coal particles. Changes in the distribution of surface sites due to oxidation and polyacrylamide adsorption on coal are studied here using the above techniques. New information on -possible conformations of adsorbed polymers is also obtained.

Jan 1, 1989

By Ray H. Hario

Background of Erie Mining Company Erie Mining Company, managed by Pickands Mather & Co., is one of the largest producers of iron ore pellets in the United States. The plant is located at Hoyt Lakes, Minnesota, sixty-five miles north of Duluth on the eastern end of the Mesabi Range. Taconite Harbor, situated on the north shore of Lake Superior, is the location of its Power Plant and shipping facilities. (Figure 1) Even though the plant commenced operation in September, 1957, its true be-ginning can be traced back to 1931 when Pickands Mather, in conjunction with Bethlehem Steel Corporation and Youngstown Sheet and Tube Company, began investi-gating the possibilities of processing low grade ores. In 1940, Erie Mining , Company was formed. During the early and middle 1940's, laboratory and pilot plant research was proven to a point where a preliminary plant was deemed feasible and built in 1948. This plant had an annual capacity of 203,200 t (200,000 long tons) per year and, until mid-1952, was the only taconite plant in existence using commercial-size equipment. During this period, ownership of Erie Mining Company was expanded to include Interlake, Inc. and The Steel Company of Canada, Limited. In 1953, authorization was obtained from the owners to build a 7.62 M t (7.5 M long tons) per year plant at a cost in excess of $300,000,000.

Jan 1, 1977

By Keivan PakIman, Maziar Pasdarpour

Transportation tunnels are highly sensitive to ground movements and are required to be stable and secure for safe operation. In urban areas, the interaction between tunnels and adjacent piles, which are widely used to support buildings and other structures, requires careful consideration. The seismic response of tunnels may vary depending on the lateral stiffness and strength of the tunnel walls, while the axial loading and seismic impact of adjacent piles may cause soil displacement and stress changes that can damage the tunnel lining. As a result, tunnel owners often impose strict limits on the design of new piles lying close to existing tunnels including maximum allowable tunnel deformation, stress change limits, and minimum tunnel to pile separation distances. This paper describes a numerical analysis of the inuence of the axial loading and seismic impact of bored pile foundations on subway tunnels, undertaen using the nite element software laxis D. ased on the results of the numerical analysis, the paper suggests a more realistic and less conservative approach for designing piles in close proximity to transportation tunnels. INTRODUCTION The interaction between tunnels and adjacent piles can cause stress changes and displacements in the soil and structures which may adversely impact structural performance and tunnel safety. It is therefore important to take account of relative load transfer and piling conguration when designing new piles in

Jun 23, 2024

By John P. Capp

In recent years limited markets have been developed for fly ash, the dust removed from coal-burning powerplant stacks, but most of it is still dumped in spoils areas at a cost ranging from 20 cents to $1.75 per ton. Aside from this cost, the creation of huge spoils areas can present a considerable aesthetic problem. Since the present annual fly ash output of about 20 million tons will probably reach 30 million by 1970, and because satisfactory disposal areas are becoming more limited, markets for much larger quantities of the waste are needed to keep disposal costs from becoming a significant economic factor in coal-burning powerplant operation. Current stress on air-pollution control and beautification, plus the vital need for good powerplant economy, makes it imperative, therefore, that coal producers and consumers expand markets and develop new applications for fly ash. Markets for established uses can be increased by making a greater effort to sell fly ash. New large tonnage markets for fly ash should be sought via more intensive, coordinated research. The economics of fly ash utilization underscores the vital role that must be played by research. To be competitive with other products, processes for the conversion of fly ash into marketable materials face difficulty in regard to two important economic factors--transportation cost and product utility--the other economic factors are favorable. Raw material costs of fly ash, for example, are quite attractive, and supply is no problem because there are many coal-burning powerplants in operation and many more are planned. Demand for products made from fly ash will grow if their utility is established and a good sales program is initiated. The major problems then are transporta¬tion costs and development of useful products.

Jan 1, 1966

By Debra C. Man, S. Thomas Freeman, F. Wiley Horne

INTRODUCTION The Metropolitan Water District of Southern California (Metropolitan) is the largest water wholesaler in southern California. Its service area spans the major urbanized portions of Ventura, Los Angeles, Orange, San Bernardino, Riverside and San Diego counties. More than 15 million people are serviced by Metropolitan through its 27 member agencies. The primary sources of Metropolitan's water supply are the Colorado River Aqueduct (CRA) and California's State Water Project (SWP). Currently, planning and design level studies are underway by Metropolitan to expand the water storage and conveyance systems within the service area for the purposes of providing increased efficiency and flexibility to manage limited water supplies, improving water quality, and increasing system reliability. The system reliability issue is particularly significant because the conveyance facilities from both the CRA and the SWP must cross the active San Andreas fault. This fault is considered to be the source fault for the anticipated "Big Earthquake" in southern California. To meet these objectives, Metropolitan's expansion plans involve a major new storage reservoir, new large diameter pipeline and tunnel conveyance facilities, more efficient utilization of existing groundwater basins, and an aggressive public awareness and conservation program. This paper focuses on the planning studies that have been carried out for over 50 miles of tunnels being considered for several of Metropolitan's proposed conveyance systems. These tunnels have ranged in length from a few hundred feet to over 42,000 feet, with depths of cover ranging from a few tens of feet to over 3,000 feet, and finished diameters ranging from 10 to 20 feet.

Jan 1, 1993

By Karel Rössler, Petr Vítek

"The Ejpovice tunnels in Czech Republic were built by EPBM in soft Clyashale, and in weathered profile with low soil overburden. The segmented liner at the cross-passage openings required support, which would not interfere with the EPBM clearance envelope during the scheduled pull back of the EPBM through both tunnel tubes. For that reason support frames or radial bolting could not be used. Steel rods inserted into the neighboring segments during the ring assembly, and later grouted were tested and realized as an innovative solution. The paper presents practical experience gained with the segmented liner support during cross-passages construction. INTRODUCTION An innovative solution using the grouted dowels was developed and realized for sixteen cross-passage openings of the twin Ejpovice Tunnels, whose construction was part of the railway track Rokycany – Plzen modernization. The following paper described practical experience gained with the innovative support of cross-passage openings, which was realized by short steel dowels grouted within the segments of the EPBM segmented liner. The paper is a continuation of the paper published in WTC 2015, which described the design aspects of the grouted dowels support, while the following paper concentrated on the production, and the performance of the dowel support observed during the breakout for the cross-passages openings. The connection by grouted dowels was patented by Metrostav, a.s. Company THE EJPOVICE TUNNELS CONSTRUCTION The Ejpovice tunnels construction started in 2013. The start of the high speed train operation through the tunnels was planned for 2018. The project was funded by the state government with the support of European Union funds of up to 70%.The tunnels were excavated with one EPBM (Earth Pressure Balanced Machine) with the external diameter of 9.89 m. The segmental liner inner diameter was 8.7 m, and thickness of 0.4 m. First, the South tunnel tube was excavated from the East portal, then the EPBM was pulled back through the South tunnel, and the excavation was started from the same portal for the North tube. After the South tube was freed from the EPBM excavation operations the cross-passage construction started. Due to the short time schedule, in the North tube the cross-passage construction started while the tunnel was still under construction. Therefore, the cross-passage construction was performed concurrently with the segments transportation, and with the EPBM pull-back through the tunnel. There were 8 cross-passages along the tunnels with a maximum distance of about 500 m, Fig.1."

Jan 1, 2016

By Barrie Butt, V. S. Znamensky

The opportunity for an exploration geologist to follow a successful exploration project through the feasibility, financing, construction, development, and exploitation phase is rare. In addition, it is not often that the exploration geologist can be present during the mining of a deposit to explain why certain actions were taken or interpretations made, and to find out how these interpretations turned out in actuality. At the Woodsreef chrysotile asbestos mine in New South Wales, Australia, mining has been- in progress for seven years and the writer of this chapter has been intimately associated with the project during the five years of exploration and seven years of exploitation. The Woodsreef mine has had major production problems, the majority of which have stemmed from the unique characteristics of the ore body and fiber. Because of the latter feature, much research has been undertaken by Woods- reef and other scientific organizations in Australia, England, and Canada regarding the Woodsreef fiber. The answers to some of the problems have negated some accepted concepts of asbestos ore milling and led to the development of new techniques. Some of these new techniques include the adoption of microscopic fiber counts as a routine procedure, the modification of accepted evaluation procedures, the development of new machines for dedusting fibers, and the recognition of a fiber with a unique milling behavior pattern and, possibly, properties. The problems experienced can be broadly divided into those associated with the geology and the physical properties of the fiber. It is possible that the same features may manifest themselves in other deposits around the world, and if they can be recognized during the exploration stages, a feasiblity evaluation may be just a little closer to the actual. The Woodsreef chrysotile asbestos deposit (latitude 30°24' S, longitude 150°44' E) is located 80 km north of Tamworth, NSW, Australia. The mine has been in production for six years and has a present scheduled mining rate of 33.11 Mt/y. An eight rock line mill treats an average of 7000 t/day, after beneficiation, and yields fiber grades in the range of group 4 to group 6 with some floats. The estimated re- serves of 30.56 Mt, with an ore to waste ratio of 1:3.0, are contained in two main zones that are designated the North and South zones. Mining started in the South Zone in 1972 and then, be- cause of the higher ore value, moved to the North Zone in 1975. Presently, there are two distinct open cuts referred to as the South and North pits that will eventually be worked together. The Woodsreef mine is owned by Woodsreef Mines Ltd. and is operated by Chrysotile Corp. of Australia Pty. Ltd., and is one of only two producing asbestos mines in Australia. The second mine is at Baryulgil, (latitude 29°13' S, longitude 152°37' E), and is operated by a subsidiary of Woodsreef Mines Ltd. This operation produces about 500 t/y for a captive market. An exploration program is being conducted in the area surrounding this small producer with a significant degree of success. The concepts developed during the exploitation of the Woodsreef deposit are being incorporated in the evaluation of the Baryulgil area, and if the Baryulgil deposit proves to be eco- nomic it is hoped that this approach will eliminate some of the major crises that have beset the production at Woodsreef during the first four years of operation. The purpose of this chapter is to describe the Woodsreef deposit, and more important, to

Jan 1, 1986