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By Neil Williams

The brecciated dolostone-hosted (Mississippi Valley-type) and associated shale-hosted stratiform Pb-Zn deposits at McArthur River occur adjacent to a major syndepositional fault, the Emu fault. Base-metal zoning, mineral parageneses, and Pb and stable isotope ratios indicate that both types of deposits formed contemporaneously from metalliferous brines that flowed into the host sediments from the Emu fault. Derivation of brines from underlying evaporitic sediments is suggested. Geochemical evidence indicates that the mechanism of ore formation was sulfate-reduction coupled with oxidation of organic matter. The textural relationships of stratiform sulfide mineralization to diagenetic dolomite concretions, chert blebs, volcanic glass shards, and inter-ore breccia beds, indicate that the reactions proceeded diagenetically within about 100 m of the sediment/water interface.

Jan 1, 1979

By Frank J. Markewicz

The expanding: demand for ilmenite for use in the manufacture of titanium pigments, the knowledge that much of this raw material comes from distant points and therefore has to include a heavy freight charge in the price of the delivered product, and the further knowledge that ilmenite occurs both in the crystalline rocks of northern New Jersey and also in some of the Triassic igneous rocks, were considerations which led to a search for ilmenite-bearing sands in southern New Jersey. That this search was successful is now history, and it is the senior author's privilege to state here that most of the credit belongs to his associates who did all of the heavy work of hand-augering for samples, and who made all of the heavy-mineral separations. We all are grateful to members of the Department of Geology at Rutgers and Princeton Universities for the use of equipment which enabled us to evaluate certain samples from our ilmenite exploration program. In addition, we wish to express our appreciation to many companies for their cooperation and for their permission to publish mineral and chemical analyses. We also acknowledge with much appreciation our debt to the geologists and engineers with whom we have had many lively and rewarding discussions relative to the ilmenite deposits.

Jan 1, 1958

By Robert W. Bruhn

The prediction of damage to a structure that is to be undermined is generally a two step process. First, the expected ground movements (the displacements, slopes, curvatures, and strains) are estimated using available (often empirical) predictive methods or survey data from a site of comparable geology, topography, and mining geometry. Second, the prospects for damage to the structure are assessed by comparing the expected ground movements to tolerable limits, some of which appear in the technical literature as damage criteria. The inverse problem of relating observed building damage to causative ground movements involves essentially the same elements. In either case, the usefulness of published damage criteria to subsidence problems may be limited in all but the most elementary cases. This paper considers several cases where structural behavior and site specific details had to be taken into account in assessing the relationship between damage and ground movements.

Jan 1, 1986

By C. A. Rowland

With the rapidly rising cost for electrical energy and the long range pre¬dictions for continued rising costs and even possible energy shortages, operation of rod, ball, autogenous and partial autogenous grinding circuits to efficiently utilize the power delivered to the mills will be demanded. This calls for a method to evaluate grinding circuit performance that is accurate, reliable and readily usable as an operating tool by supervisory, technical and operating personnel. Neither the Rittinger and Kick theories of comminution,(1) which preceded the Bond Theory by more than 50 years, had a mathematical means that could be used to predict and evaluate the performance of crushers and grinding mills used to comminute ores and rocks. This severly limited the practical use of these two theories, which were contradictory to each other. They have been superseded by the Bond Third Theory of Commnution.(1)

Jan 1, 1976

By Donald E. Steif

The Tower Mill is a vertical stirred mill using steel balls or pebble grinding media. This device is designed for fine grinding at significant power savings when compared to conventional tumbling mills. This paper describes the machine, its operation, application, and performance for wet grinding.

Jan 1, 1984

By Arthur M. Ribe

In my experience, nothing helps me better to get off to a good start in preparing a paper or a talk than a copious consultation with a comprehensive dictionary. I also feel defining the perimeters of a particular subject is helpful to the listener and reader. Sometimes thus precisely defining even the most common of words is helpful. Our general topic this morning as all of you know is "Transportation of Industrial Minerals." The definition of transportation given by the dictionary which I think is appropriate here is: "Systems and modes of conveyance of persons or goods from place to place." Our preceding panelists have outlined for you the state of the art inso¬far as systems and modes of conveyance from place to place are concerned today via rail, water and motor. My assignment is somewhat different as indicated by my topic, "The Traffic Manager in an Industrial Minerals Operation."

Jan 1, 1969

By Craig Ammar

JAMIE DAVIS: Our next speaker is Craig Ammar. He's director of equipment management for Cyprus Climax Metals Company. He has, prior to this assignment, been responsible for maintenance at Bagdad Copper, Cyprus' Miami smelter, and Thompson Creek. Like Jerry, he's very shy and retiring, and doesn't have any strong opinions about maintenance. INTRODUCTION CRAIG AMMAR: The ultimate goal behind implementing a proactive equipment management process is to provide capacity assurance and ultimately increase an organization's ability to generate revenue while reducing operating costs. Targeting such lofty objectives has brought many an organization to its knees, utilizing new maintenance techniques, concepts, and technology aimed at making our lives better and more organized. The root cause of such frustration generally stems from a lack of understanding or support for the fundamentals of implementing a proactive equipment management process. There are just two types of maintenance programs, reactive and proactive. It's an established fact that you need a little of both to run an effective equipment management process, obviously more of one (proactive) than the other. Here are some telltale signs that your equipment management process is in trouble: -Maintenance is performed as a knee jerk reaction when equipment fails. -Repeated and frequent equipment failures occur, with no focus on eliminating the root cause. -Sketchy, inconsistent, unclear preventive maintenance is performed or there is no support for the preventive maintenance process. -No predictive maintenance technology process is in place, or little support for predictive maintenance exists. -Less than 50 percent of your work is generated by the maintenance group resulting from inspections.

Jan 1, 1998

By C. G. Anderson

Today, with a stringent economic and environmental climate prevailing in the copper business, there is increased interest in evaluating new processing alternatives for production. Hydrometallurgical pressure oxidation of copper concentrates is one of the more viable approaches and several technological candidates have emerged. Of these, an overlooked but, ironically the first industrially proven methodology, utilized nitrogen species catalyzation in the oxidizing pressure leach system to produce copper via SX/EW. Given its many inherent process advantages, this may prove to be a feasible process alternative for the future. In this paper, the history of the system and its application to copper concentrates and ores will be outlined. In particular, a novel methodology for effective recovery of precious metals from chalcopyrite concentrates will be discussed. Finally, the perceived economics of chalcopyrite concentrate treatment with this unique industrially proven process will be delineated.

Jan 1, 2001

By R. E. Johnson, W. Kat, B. R. Palmer, van Sandwijk A., G. Van Weert, S. Honingh

In-plant recycling of dust from iron making BF's creates undesirable circulating loads of volatile trace elements such as zinc and lead. Disposal of such dusts creates environmental problems, hence a separate treatment is indicated. Since the bulk of the zinc and lead compounds occurs in the fine dust fraction; hydrocycloning the slurry from the BF gas cleaning operation results in upgrading the material for treatment. A process has been proposed, whereby the zinc and lead are solubilized from the fine fraction with spent hydrochloric acid from steel pickling. The stoichiometry of this autoclave oxidation process is adjusted to simultaneously precipitate, by oxyhydrolysis, most of the iron for recycling to the BF's. Lead and zinc are successively recovered from the filtrate as low chloride precipitates. This paper describes additional testwork, leading to the design of a pilot plant which was planned to begin operation in 1992.

Jan 1, 1993

By Ian J. Corrans, Gary Johnson, John E. Angove

Activox® is a hydrometallurgical process used to oxidise sulphide concentrates. The process is based on two relatively simple, established unit operations; i.e. fine or ultra-fine milling (UFM) and pressure oxidation under mild conditions. An under-standing of, and ability to control the pulp chemistry during oxidation has resulted in the successful Activox® treatment ( on a batch scale) of a wide variety of sulphide flotation concentrates; • pyrite/arsenopyrite + gold • pyrite/chalcopyrite + gold • pyrite/chalcocite + gold • pyrite/enargite/tetrahedrite + gold Oxidation rates are rapid (1-2 hours retention time) and gold

Jan 1, 1995

By W. J. Guay

Carbonaceous gold ores containing gold dispersed in sulfides are refractory to cyanidation because: (1 ) the carbonaceous materials adsorb gold during cyanidation; (2) a portion of the gold s so finely dispersed in the sulfide mineral lattice as to preclude contact with cyanide solution; and (3) a portion of the gold is chemically combined with carbonaceous material. Techniques which have been used to treat these ores are: (1) roasting or chemical oxidation to decompose sulfide and carbonaceous materials; (2) flotation to reject carbon; (3) the use of kerosene or other reagents to passivate the adsorptive carbon compounds; (4) carbon or resin in pulp; (5) flotation of a bulk concentrate which is treated by one of the above methods; and (6) the use of chelating agents which have a stronger affinity for gold than the activated carbon in the ore.

Jan 1, 1981

By W. J. Guay

Carbonaceous gold ores containing gold dispersed in sulfides are refractory to cyanidation because: ( 1) the carbonaceous materials adsorb gold during cyanidation; (2) a portion of the gold is so finely dispersed in the sulfide mineral lattice as to preclude contact with cyanide solution; and (3) a portion of the gold is chemically combined with carbonaceous material. Techniques which have been used to treat these ores are: (1) roasting or chemical oxidation to decompose sulfides and carbonaceous materials; (2) flotation to reject carbon; (3) the use of kerosene or other reagents to passivate the adsorptive carbon compounds; (4) carbon or resin in pulp; (5) flotation of a bulk concentrate which is treated by one of the above methods; and (6) the use of chelating agents which have a stronger affinity for gold than the activated carbon in the ore.

Jan 1, 1981

By John L. Watson, Suren Mishra

Many of the wastes produced by modern steel plants are pulps or sludges containing significant concentrations of iron and displaying some ferromagnetic characteristics. These waste materials are often suited to treatment by magnetic cycloning to produce a high solids content underflow and a clean water overflow. Alternatively in the classification mode, the magnetic cyclone can produce a high iron underflow product for recycling by discarding fine non-magnetic material to the overflow. Results for the treatment of a variety of steel plant wastes in 5.0cm, 2.5cm and 1.25cm diameter cyclones, operating with and without an applied magnetic field, are presented. It is demonstrated that the magnetic cyclone increases solids recovery to the underflow product, especially at finer particle sizes and for higher solids content feed pulps.

Jan 1, 1992

By Stephen F. Munsell

The development of transportation systems for mined materials has historically been characterized by steadily increasing sizes in basic hauling units. This is especially true for open pit mines for which success is dependent upon the economical transportation of vast quantities of material. The depletion of high grade ore reserves has mandated a tremendous increase in the size and complexity of the ore haulage systems necessary for open pit mines, These increased demands were served by rail haulage systems in the early large open pit copper mines while later developed properties opted for the flexibility and lower initial costs of truck haulage. Now, we find the trucks being displaced as large overland belt conveyors tackle the problem of handling these ever larger quantities of low-grade ores with accompanying overburden ratios that can run as high as 10:1 or even 15:1. The basic development of large conveyors with shiftable sections and modular belts has generally taken place overseas, during the last few decades. The coal fields of central Europe proved an ideal testing ground for conveyor innovation because the low density and natural friability of the material created an ideal medium for transporting by belt conveyor. Now these proven ideas are being considered for and implemented into both the soft and hard rock mining industries of the United States.

Jan 1, 1978

By David Hurth

JOHN HAMRIC: Our next topic leader is David Huth, superintendent of sulfuric power generation, DAP, and shipping for IMC-Agrico, Nichols Plant, Mulberry, Florida. With a title like that it's no wonder he believes in empowerment. His topic today is "The Triumphs and Pitfalls of Using Empowerment Techniques." DAVID HUTH: Empowerment and its benefits are a desirable alternative to the traditional management structure. The difference between the two is the amount of decision- making authority and responsibility given to individuals by a supervisor. Just what is empowerment and how does it work? Empowerment is relinquishing to individuals the authority and responsibility to make daily decisions. Can everyone be empowered? What if they make a wrong decision? Will I empower myself out of a job? These are questions that all managers have when they hear the word empowerment. In today's fast-paced and high-pressure business environment, the old way of managing people must be replaced with a new approach. No longer can we, as managers, make all the decisions. The increased work loads due to downsizing, consolidation, and synergies have stretched us too thin. What about our employees? How can we motivate them into the high-performance teams that our companies are demanding? What possibly could satisfy both these issues? The solution to these problems can be solved with the power of employee empowerment. Employee empowerment will not only lessen the load on managers but will build teamwork, motivation, and pride into the employees who work for the managers who use it. American business was rudely awakened in the early 1980s when the Japanese companies not only caught up to American companies but literally flew by them. America was fat, dumb, and happy after World War II. Why wouldn't they be? They had all the factories. Everyone else had to rebuild. So for 40 years American business lounged in the limelight of very little true competition. But times change. Unfortunately, American business did not. Now the cry to perform in the new global economy has come down from the corporate boardrooms. Down through the ranks it has been felt. Guess who is supposed to make it work? But where are all those people who are going to make this rejuvenation and corporate renaissance possible? Many of them are gone-lost in downsizing, synergies, and rightsizings

Jan 1, 1998

By Hugh E. Cronin, Joseph J. Coluccio

The Columbia Slough Consolidation Conduit Project is a 12 ft. 0 in. inside diameter—15 ft. 4 in. excavated diameter tunnel, 8,300 lf. in length. The tunnel is divided in two parts a 4,460 lf. reach to the West and a 3,770 lf. reach to the East separated by a flow regulation structure in the middle. The project was built for the City of Portland, Oregon Bureau of Environmental Services (BES) by the Frank Coluccio Construction Company (FCCC) Seattle, Washington under a $22,600,000.00 contract starting in 1998 and completing the contract in 2000 at a total cost to the City of $25,448,000. An increase of 12.6% from the original contract. The tunnel was constructed in an alluvial sediment that ranges up to 1,500 feet thick. The sediment varies from ?ne silty sand and sandy silt (SM-ML) to coarse sand and gravel (GP-GM) with varying quantities of cobbles and boulders. Most of the tunnel was constructed above the water table although one reach of almost 1,000 lf. had water to above the tunnel crown. The contractor, FCCC, used a Lovat 15 ft. 3 in.900 hp shielded TBM with multiple doors (4) of variable opening to excavate and support the tunnel. Tunnel supports were 5 in. WF 16 lbs. per foot at 4 ft. spacing and4 in. Douglas Fir lagging. Tunnel excavation was worked in 10 hour shifts with additional equipment maintenance and repair on the off time. The original Geotechnical Design Summary Report (GDSR) established a baseline for contractual purposes of slightly over 5 boulders (between 12 in. and48 in.) per foot of tunnel. (Table 1) At the pre-bid conference, three test pits were excavated to approximately tunnel invert, one at each end of the project and one in the middle near the flow regulation structure. The test pits encountered a few boulders but did not seem to support the five boulders per foot (varied from one boulder per foot of tunnel to eight b/lf.). Subsequent to the pre-bid meeting and the test pits, BES issued any addenda which changed the baseline boulder quantity in the GDSR to 1.7 boulders per foot of tunnel (varied from0.2 to 3.5 boulders per foot) a reduction of 67% from the original baseline. It is interesting to note the two separate tunnel reaches and how they were evaluated in the GDSR. Originally the Eastern portion of the work was projected at5.08 boulders per foot of tunnel and the Western portion at 5.30 boulders per foot of tunnel for a variance of less than 5%. In the revised quantity the Eastern portion was projected at 2.01 boulders per foot of tunnel and the Western portion at 1.42 boulders

Jan 1, 2003

By Steven I. Majtenyi

There is a growing interest among transportation planners to make more use of the subsurface to preserve the landscape and make transportation more efficient and economical. At the present time, utilization of the underground for transportation facilities is severely restrained by the adverse environmental impact and high construction costs. However, recent studies performed by the United States Department of Transportation indicate that, in spite of such problems, the volume of underground construction has significantly increased during recent years and projections point to continuation of these trends(1). It is estimated that the total volume of transportation tunnel construction will exceed $4 billion in this decade. This level of Investment justifies a significant research program. Due to the common interest in transportation tunnels and to the similarities of problems encountered during their construction, the tunneling research activities of the Federal Highway Administration (FHWA) are closely coordinated with the programs other agencies of the U. S. Department of Transportation DOT); specifically, the Federal Railroad Administration (PRA) and the Urban mass Transportation Administration (UMTA). The FHWA is responsive to the particular needs of these agencies but will benefit from the research results obtained also. In 1971, the Office of Secretary, DOT, initiated plans for an overall coordination of the DOT, FICA, UMTA, and FHWA tunneling research activities. The objectives of this effort have been to reduce tunneling costs by 30% and to increase the rate of excavation by 200% within 10 years. This coordinated program was developed and promoted during 1972 and 1973 by Dr. Eugene L. Foster, at that

Jan 1, 1974

By Wayne R. Hopkins

Southern Arizona has one of the world's principal concentrations of copper ore bodies. Twenty miles south of Tucson, close to the Mexican border at Sahuarita in Pima County, is the Twin Buttes mine. In mid-1973, the Anaconda Company and American Metals Climax Incorporated (AMAX) established a 50-50 partnership to operate and expand the Twin Buttes property. Anamax Mining Company was established as the operating company for this joint venture. The production from the Twin Buttes mine is shared between the two partners who market independently. A major expansion of the Twin Buttes operation has included an accelerated stripping programrne for the pit, an expansion of the sulphide concentrator, the construction of an oxide leach plant and a 57 MW diesel generating power station. Part of this major expansion, the large tonnage oxide processing plant was brought on stream in 1975 and is now close to design capacity. The "mine to market gap" has been closed by producing high-purity copper cathodes at the mine site from oxide ore reserves. By using a hydrometallurgical process route, copper production is possible with negligible effects on the environment.

Jan 1, 1976

By Alexander N. Winchell

The cities of St. Paul and Minneapolis are located side by side on a double loop in the Mississippi River near the eastern boundary of Minnesota. Both cities lie on both sides 'of the Mississippi River, which in this region describes an S-shaped curve. The two cities together have a population of over 600,000 people, gathered in an area which has grown to be a single urban district inasmuch as the two cities have expanded until they occupy all the territory formerly between them, though the business centers are ten miles apart. St. Paul is located at the head of navigation on the Mississippi River and Minneapolis, farther upstream, at the Falls of St. Anthony. A recent water¬power development below the Falls of St. Anthony, constructed by the Federal Government, has at the same time made possible navigation to the foot of St. Anthony Falls through a lock around the dam which replaces the former rapids. Minneapolis, in 1920, had a population of 380,000 people, and St. Paul, 235,000. The two cities occupy land at an elevation of 700 to 900 feet above sea level. The average elevation is slightly less at St. Paul. Minneapolis has nearly 4,000 acres of parks and park¬ways, while St. Paul has nearly 2,000.

Jan 1, 1920

By Charles D. Litton

This paper presents a description of the hazards of smoke from fires, the detectability of smoke using smoke sensors, and the operational characteristics of such detectors. It places in perspective the advantage that smoke detectors have over other forms of fire detection and also provides a discussion of smoke as a significant fire hazard.

Jan 1, 1992