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By M. P. Juszli

During the 1980's, a revolution has been taking place in industrial minerals marketing. Transportation deregulation and a handful of creative marketing and distribution managers have completely changed the rules for marketing many industrial minerals. Minerals are being trans-ported much farther than in prior decades and at much less cost. Bulk and package terminals are becoming increasingly common as a means to take advantage of freight rate savings and to provide enhanced service to far-away customers. Water and rail transportation are being used increasingly to penetrate markets considered unreachable Just a few years ago.

Jan 1, 1989

By Carrie Smith

This fall, the Society for Mining, Metallurgy & Exploration (SME) will begin a new chapter by welcoming its new executive director and chief executive officer (CEO). Melissa Russell, a successful nonprofit executive with more than 30 years of experience in global association management, officially stepped into the role on Sept. 29, 2025. She succeeds longtime CEO Dave Kanagy, CAE, who is retiring in March 2026 after more than two decades of transformative leadership. “I am honored to begin this new chapter with SME and inspired by the vital role this community plays in shaping our world,” said Russell. “I look forward to listening, learning and working alongside this remarkable group of professionals to advance innovation, champion sustainability and create a brilliant future together.” Russell brings a deep portfolio of leadership experience in technical and industrial associations to SME. Most recently, she served as executive director of the Institute of Electrical and Electronics Engineers (IEEE) Computer Society, the largest of the IEEE’s 39 societies, with more than 50,000 members across 150 countries. During her tenure, she strengthened global engagement, advanced financial sustainability and launched strategic humanitarian initiatives.

Oct 1, 2025

By R. Hemp

This paper describes work carried out to obtain a heat balance in the B3 shaft longwall stope at Blyvooruitzicht gold mine. Recordings were made of the temperature of the air and chilled water entering and leaving the section during three periods, August 1 September 1977, November 1 December 1977 and March 1978. These recordings, together with numerous other measurements were used to determine the rate at which heat was being removed from the section by the various fluids flowing through the section. The rate at which heat was entering the section was then calculated, by considering each source in turn. These two sets of figures made it possible to draw up a heat balance, and also obviously gave vital information on the magnitudes of the various heat sources and on the methods used to remove heat. In general reasonable heat balances were obtained, the errors being in the range -6 per cent to +22 per cent.

Jan 1, 1980

By Raymond E. Riethmann

El clasificador de espiral fue diseñado originalmente para circuitos cerrados de molienda. Desde entonces se ha aplicado con éxito a otros trabajos de clasificaci6n donde se necesita realizar un corte de dos productos. Inherentemente a las cualidades especiales de este cla- sificador está especialmente preparado para: clasificar, lavar, o agotar materiales tales como minerales, roca fosfática, arenas, carbbn, conchas de ostra y sales fosfáticas. Presentamos ahora las características de operation, flexibilidad de diseiio y líneas maestras para una apropiada aplicación.

Jan 1, 1982

By A. J. Hendron, L. L. Oriard

INTRODUCTION Controlled blasting is used at some time during most civil engineering projects where there is rock excavation. Controlled blasting is often necessary because the blasting must take place in the near proximity of adjacent structures. In other instances, the blasting is controlled because a smooth perimeter is desired to minimize rock support and overbreak. The construction of tunnels and shafts for subways, rock excavations for foundations and the excavation of road cuts for interstate highways, sometimes require blasting operations which must be conducted in an urban environment. Unfortunately, blasting operations produce unwanted sounds and vibration along with their beneficial effects. Thus, in the writing of specifications for blasting in an urban environment, potential damage to adjacent structures by ground vibrations must be considered, possible damage to windows from airblasts must be considered, potential damage from fly rock must be considered, and the discomfort to people from ground vibrations, airblast, and noise must be taken into account. The contractor or the owner's engineer is faced with determining the maximum weight of explosives which may be detonated without damage to structures on adjacent property. If the weight of explosive is overestimated, the resulting damage to adjacent structures may result in costly losses. But, if the engineer or contractor is too conservative, and the weight of explosive becomes too restrictive, progress of the project may be curtailed and the cost of excavation will increase accordingly. The potential for damaging adjacent property is becoming more important in construction operations today. In the past, the plaintiff had to prove negligence in some states in order

Jan 1, 1997

By K. N. Han, M. C. Fuerstenau

Challenges in five major areas of hydrometallurgy are presented and discussed. These are: leaching low-grade oxide and sulfide ores; oxidative leaching of sulfide concentrates; processing refractory ores; bacterial leaching and processing: and secondary metal recovery.

Jan 1, 1989

By Karin Bäppler

Hydropower produces almost two-thirds of the world’s renewable electricity generation and delivers a major contribution on the ambition of the Paris Agreement and Sustainable Development Goals (SDG) with a range of benefits to society and environment. These include clean and flexible generation and storage in addition to reduced dependence on fossil fuels and avoidance of pollutants. The Limberg III PSP is one of the European projects that addresses the implementation of the UN SDGs. The challenge of the project is the construction of a 770 m long pressure shaft to be excavated with a TBM at an inclination of 42°.

Jun 13, 2023

By Noel C. Joughin, Orrie Fenn, Brian E. Protheroe

Work has shown that the use of high-pressure water jets enhances the performance of mechanical cutting in very hard rock. To assess the potential of this approach for use in conjunction with free rolling cutters, a series of tests has been conducted using both disc and button type cutters, to determine the relative effects, on cutter performance, of variations in relevant jet and cutting parameters. In these tests it was found that water jet assistance can result in reductions in the forces on a free rolling cutter typically of the order of 40%.

Jan 1, 1985

By Steve Kral

The Red Dog zinc-lead deposit, said to be the world's second largest, is located inside the Arctic Circle in northwestern Alaska - a location too harsh and remote for some mining companies but just right for Cominco Ltd. The complex has been in operation since November 1989 and is producing 508 kt/a (560,000 stpy) of zinc concentrate, 109 kt/a (120,000 stpy) of leadconcentrate and 45 kt/a (50,000 stpy) of an Imperial Smelter Feed, a combined zinc-lead mixture that is too small to separate. All of this concentrate production derives from a relatively modest mine production of 5.4 kt/ad (6000 stpd) extracted from a surface pit. Despite being a high-grade zinc-lead deposit, Red Dog's metallurgy is complex, requiring a very fine grind and use of column cells for flotation. The Red Dog complex is located in the DeLong Mountains. They are characterized by eight stack and folded thrust blocks that contain sedimentary and igneous rocks. The Red Dog deposit is located in the second lowest thrust and ist hosted by late Mississippian to Permian age black shale, the Ikalukrok member of the Kuna formation. The Red Dog mining complex is operated by Cominco Alaska, Inc., a wholly owned subsidiary of Cominco American, Inc, which, in turn, is owned by Cominco Ltd. In 1980, the deposit region was acquired by NANA Corp. as part of the Native American Claims Act Settlement of 1971. NANA is one of 12 such Native Corporations in Alaska. In 1982, NANA and Cominco American signed a develop¬ment agreement and formed Cominco Alaska to manage the project.

Jan 1, 1992

By David Jenkins

Grefco Inc. operates two diatomite mines in the western Santa Ynez Mountains. The larger of the two mines, the Palos Colorados Mine, is located approximately seven miles southeast of Lompoc. The Miguelito Mine is located about two miles south of Lompoc on the west side of the Miguelito Canyon. Diatomite from the Palos Colorados and Miguelito mines is trucked to the Grefco plant at Lompoc for processing (Figure 1). HISTORY Grefco, Inc. evolved from the originating Dicalite Company which in 1929 began operations at the Walteria plant in the Palos Verdes Hills south of Los Angeles. In 1942 Dicalite leased the Palos Colorados mine at Lompoc. In 1944 the Dicalite Company was purchased by Great Lakes Carbon Corporation.

Jan 1, 1995

By Kim A. Lapakko, William W. III White

The ASTM standard method D 5744-96 was developed to provide a well-defined kinetic test protocol, conducted under controlled reaction conditions, with the intent of generating reproducible results. A preliminary indication of the repeatability of a simplified alternative method (MN DNR method) was assessed and results from the MN DNR method were compared to those from the ASTM method. To provide an indication of repeatability, six samples from three different rock types were subjected to dissolution testing for periods of 20 to 68 weeks. Drainage pH values at the end of the tests were within 0.5 units in all cases and within 0.05 units in four cases. The percent difference from the mean for overall sulfate rates from paired cells ranged from 0.04 to 1756, with a median of 6.3%. Nine samples from four rock types were subjected to both MN DNR and ASTM tests for periods of 20 to 132 weeks. The difference in final drainage pH values forsix of the samples was less than 0.1 unit, and these values were less than pH 3.65 or greater than pH 8.0. The final drainage pH difference for the last three samples ranged from 0.15 to 0.4, and these values were ill the pH range of 6.2 to 7.2. The sulfate release rates for the periods of record for the MN DNR method were 70 to 150% of those for the ASTM method, with a median value of 110%. Sulfate and calcium release from the two methods was not substantially different. The MN DNR method typically produced higher magnesium release.

Jan 1, 2000

By D. S. Choi

The paper presents the result of analysis of subsidence data collected from coal mines operating in Northern West Virginia and Southwestern Pennsylvania. A particular emphasis la placed on the measurement of the angle of draw for the protection of surface structures.

Jan 1, 1986

By Ronald E. Heuer

The significance of surface settlement over soft ground tunnels is well recognized. Cracked buildings, streets transformed into lakes, broken utility lines, to underpin or not to underpin--all are familiar problems. The basic causes of surface settlement are recognized. Possibly the most common and troublesome cause is "lost ground" during construction. Lost ground refers to removal of a larger volume of ground (Ve) than is eventually occupied by the final tunnel structure (Vt). A number of sources of lost ground in shield tunneling have been identified, as illustrated in Fig. 1. These include 1) face loss, 2) overcutting loss, 3) annular tail void loss, and 4) loss through the lining. The ground generally does not stand unsupported around the completed tunnel lining as illustrated in Fig. 1, but moves in to fill the lost volume, resulting in subsidence of the overlying ground surface as shown. As suggested in Fig. 1, lost ground and surface settlement associated with overcutting and the annular tail void tend to occur systematically along the tunnel length. This "systematic" lost volume is "limited" in the sense that it is restricted to an upper limit determined by the shield and lining geometry. Partially controlled face loss may sometimes contribute to this systematic loss. This lost volume is commonly a few percent of the nominal tunnel volume. The resulting surface settlement over the tunnel is commonly in the range of a few inches or less and develops over a period of hours to days. Although they may have a significant impact on surface facilities, systematic ground loss and settlement frequently have little adverse effect on tunneling progress.

Jan 1, 1976

By D. J. Beeby

California's Surface Mining and Reclamation Act (SMARA) was passed in 1975 to identify and protect mineral resources in areas of high land use conflict and ensure reclamation of mined lands. Under SMARA, aggregate resource availability is quantified and compared to forecasted demand in specific market regions. Fifteen regions studied thus far cover 51,800 km2 (20,000 sq miles) and contain 45 Gt (50 billion st) of high-quality aggregate resources that have been legally designated as "regionally significant," providing a measure of protection previously unavailable. SMARA reports and state testimony at local hearings have supplied objective information and helped reduce conflict in mine permitting decisions.

Jan 1, 1987

By Alastair R. Biggart

ABOUT BENTONITE TUNNELLING Much has been written and many learned papers given on this subject whose generic term is Slurry Tunnelling. This paper is about the particular form of slurry tunnelling known as the Bentonite Tunnelling System. This method. of tunnelling was invented by J.V. Bartlett of consulting engineers, Mott Hay and Anderson in 1964. The general principles are incorporated in British Patent No. 1083322. It was not until the early 1970's that serious experimental work was started to prove the technical feasibility of the process. In the U.K. in 1971 Edmund Nuttall Limited started on an experimental length of 3.8m diameter tunnel at New Cross in London. In Germany at about the same time Wayss and Freytag were starting on a 3.7m diameter collector sewer tunnel in Hamburg. In Japan early slurry tunnelling work was carried out in the 1960's. In the early 1970's a large number of slurry tunnels of various diameters were carried out in that country. This paper is being presented at a time when this system of tunnelling has become an accepted method throughout the developed world. As a result of the work carried out so far there is now a large amount of data existing regarding the effects on the ground in the immediate area of the tunnel, settlement at the surface and the ability of the system to cope with ground varying from clays to coarse gravels and containing large erratics such as granite boulders. The decade of the 1970's has therefore seen a very rapid pace

Jan 1, 1979

By S. Behl, S. Mathur

It was previously reported that dolomite samples from different locations showed varying flocculation behavior with poly(ethylene oxide) (PEO). In this study, a Florida dolomite sample was examined, and it was determined that palygorskite associated with dolomite was responsible for its flocculation with PEO. A detailed characterization of dolomite samples from different locations was made by electrokinetic, XRD and FT-IR analyses, and the relevance of these characteristics to flocculation with PEO is discussed.

Jan 1, 1996

By Dean J. Acuff

An overview of new size reduction technology involving the use of two-mass natural frequency vibration applied to a totally enclosed elongated drum. Material moves with a drum-like rotary motion with exposure to constant, aggressive, high frequency agitation for faster reduction and enhanced product quality. A proven, patented design with few moving parts, a vibrating mill drum provides the desirable environmental benefits of a totally enclosed rotary drum but without the same interfacing difficulties. Natural frequency design has reduced energy demand which is met by low horsepower, self-contained, motorized drives to dramatically reduce the cost per ton of finished product.

Jan 1, 1993

By Martha McJunkin, Lawrence Pietrzak

This paper describes and demonstrates the application of systems analysis and mathematical modeling techniques in the planning of actual tunnel projects and research and development to improve tunneling techniques. A recently completed tunnel project located in Utah is used as an example. Although cost estimating computer programs are used in tunnel project planning, the introduction of performance modeling, simulating the time to excavate, has added advantages that are explored here. The performance/cost tunneling model (TM) described herein mathematically simulates on a high-speed digital computer the important activities of a number of tunneling techniques accounting for activity interactions, variable external environments, mechanical failure, and other uncertainties. A cost accounting segment is included to facilitate cost-effectiveness comparisons. It is shown that, when combined with informed judgment and appreciation of limitations, the TM can be a useful tool that may help improve tunneling operations and cost estimation, for example, by achieving more balanced system designs or bounding the performance/cost implications of geologic and other uncertainties. Ultimately, this might lead to more competitive bids and greater profits. The need for systems analysis and modeling in tunneling research and development (R&D) is well recognized and documented.(1-5) In R&D one must seek broadly useful solutions to the basic problems of face fragmentation, materials handling, ground support, and environmental control. These solutions must take account of the interdependence of these elements and, for a variety of ground conditions, the limitations or constraints that any innovation in one element may impose on total system performance and cost. In this regard the structure and logic of the TM has been kept as simple and modular as possible so

Jan 1, 1974

By Fred N. Kissell

Work done by Foster-Miller Associates under a Bureau of Mines research contract has developed methods to increase significantly the amount of fresh air that reaches the front of a continuous-mining machine. The emphasis was on removing methane build- ups that occur at the cutterhead. Using a full-scale plywood mockup of a coal mine working face area, the study showed that in many instances only about 20 pct of the fresh air heading towards an exhaust brattice or tubing actually gets to within 1 ft (0.3m) of the face. The key to providing more air at the face is to enhance and move forward the natural airflow pattern. This change in the natural airflow pattern can be accomplished by taking advantage of the air-moving abilities of the conventional water spray. It was discovered that if all the water sprays on the machine were realigned, then ventilation efficiencies of 70 pct or more were achieved regularly. This meant that if 9,000 cfm (4.2 m3/s) was entering the brattice, at least 6,300 cfm (3.0 m3/s) of this was reaching to within 1 ft (0.3m) of the face. This water spray realignment consists of placing a few nozzles on the side of the machine opposite the curtain and also tilting the front sprays slightly towards the curtain side. Recently, two underground tests and two additional independent laboratory tests of the water "Spray Fan" have been completed. In general, they have confirmed the performance of the Spray Fan system, but they also have provided useful information as to its difficulties and limitations.

Jan 1, 1980

By Y. Topkaya, R. E. Johnson, B. R. Palmer, R. B. Bhappu, Ronald J. Roman

The hydrodynamics of the leaching solution in leach heaps is known to be one of the important variables in the performance of the heap. The solution hydrodynamics are also important in the decommissioning of a heap where the aim is to flush out the residual dissolved metals and the remaining reagents. Chemical engineers have studied the hydrodynamics of "trickle bed" reactors for 40 years in an attempt to relate the performance of trickle bed reactors to flow conditions. Their work is reviewed with emphases on areas of similarity to heap leaching.

Jan 1, 1993