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By S. Garcia, J. Gebhardt, D. McBride, A. Hernandez, A. Esplín, M. Cross

The Minera Yanacocha operation consists of several heaps interconnected with ponds and gold recovery plants and presents various operating challenges. A comprehensive process model has been developed in order to better understand the effects of certain operating parameters and inventory issues. An integral component of the process water/mass balance is a model of each heap that describes heap behavior based on the individual characteristics of the heap. The heap models are linked to a mass balancing program in order to track flows and concentrations throughout the circuit. A case study of the process heap model is presented for the La Quinua heap, including results for the normal base line operation and several operational problems such as loss of solution flow to the heap (i.e., pump failure), increased flow to a section of the heap (i.e., pond volume control), effect of significant rain events, and impact of a change in material properties (i.e., change in ore type). The impact on heap operating efficiency is discussed with regard to effects on recovery and gold solution grades.

Jan 1, 2007

By Bertrand L. Johnson

Barite, the natural sulfate of barium (BaSO4), is the most important barium mineral. Normally it is white (opaque to translucent), but impurities sometimes render it yellow, gray, blue, brown, red, or black. Brown or red stains are commonly caused by iron oxide. Barite is unusually heavy (specific gravity, about 4.5); in fact, it is one of the heaviest of the nonmetallic minerals. It is brittle and fractures unevenly. The hardness of barite ranges from 2.5 to 3 but is usually about 3. It can be scratched by a copper coin. Pure barite contains 65.7 percent BaO and A.3 percent S03. Much of the crude barite ore mined, however, contains impurities; thus it has a lower content of barite and consequently less barium oxide. Commercial analyses show its total BaSO4 content. Barium also occurs in nature as the mineral witherite (BaCO3), which, however, is not common in the United States, and commercial deposits have been found only in California. Witherite is a yellowish-white, light-gray, or Kite mineral with a specific gravity of about 3, a hardness of 3 to 4, and an uneven to subconchoidal fracture.

Jan 1, 1941

Ground control problems in the form of large dome or wedge collapses have been experienced at Tau Lekoa Mine since production began. Crush pillars in various configurations have been used and through a process of trial and error the current pillar layout has been derived. A strike pillar layout is used and additional mid-panel pillars are left spaced a maximum of 10m or 16m apart, depending on conditions and mining direction. Pillar spacing is based on an empirical relationship between fallout height and pillar spans. Analysis of the spatial distribution of large falls of ground indicates that there may be several geotechnical relationships contributing to stable pillar spans. The current focus is to define the relationship between geotechnical areas and hangingwall stability so that area specific support strategies can be formulated that could result in increased production efficiencies. Depuis le début de la production, la mine Tau Lekoa a connu des problèmes de contrôle au sol, sous la forme d’effondrements de grands dômes ou coins. Des piliers d’écrasement, dans des configurations variées, ont été utilisés et une série d’essais a résulté en la disposition de piliers en cours. Une configuration de piliers de direction est utilisée, et des piliers mi-panneau supplémentaires sont laissés, espacés d’un maximum de 10m ou 16m, selon les conditions et la direction de la mine. L’espacement des piliers est établi sur une relation empirique entre la hauteur des retombées et les intervalles entre piliers. L’analyse de la distribution spatiale de grandes tombées de terrain indique qu’il peut y avoir plusieurs relations géotechniques qui contribuent à des intervalles de piliers stables. L’intérêt présent est de définir la relation entre les zones géotechniques et la stabilité du toit, pour pouvoir formuler des stratégies de support spécifiques à un endroit, ce qui entraînerait des accroissements de production. Bodenkontrollprobleme traten seit Produktionsbeginn in Form von grossen Keil oder Dachhaubenbrüchen in der Tau Lekoa Mine auf. Bruchpfeiler in verschiedensten Konfigurationen wurden verwendet und auf Grund empirischer Fakten wurde das gegenwärtige Pfeilerlayout abgeleitet. Ein Layout für Strukturpfeiler wird verwendet und zusätzliche mittig situierte Pfeiler in einem Maximalabstand von 10m bis 16m installiert, abhängig von den Konditionen und der Vortriebsrichtung.Der Pfeilerabstand basiert auf dem empirischen Verhältnis Fallhöhe und Pfeilerspannweite. Die Analyse der räumlichen Verteilung großer Bodenabsenkungen deutet an, daß es einige geotechnische Verhältnisse geben kann, die zu stabilen Pfostenspannweiten beitragen. Der gegenwärtige Fokus soll das Verhältnis zwischen geotechnischen Bereichen und Stollendeckenstabilität definieren, damit bereichspezifische Unterstützungsstrategien formuliert werden können, welche in erhöhter Produktionsleistung resultieren könnten.

Jan 1, 2003

By Christopher C. Jobes

Computer-assisted control of a mining machine can place the operator in a safe, remote location. A guidance system aids remote positioning of a mining machine by determining its position and heading. The mechanical position and heading system (MPHS) is one of several guidance systems being developed at the U.S. Bureau of Mines. The MPHS uses linear position transducers (LPT's) to provide navigation information during face maneuvers. This report presents an overview of the MPHS theory and implementation, including recent design modifications made for more successful underground testing. This report also presents the experimental setup and procedure for the underground test. The test showed that the MPHS provides reliable and accurate results and can, therefore, provide useful guidance information for face navigation.

Jan 1, 1992

By R. Van A. Mills

Rapid deterioration and destruction of metal equipment in oil and gas fields cause waste of resources and financial losses that must be lessened or eliminated if operations in many important fields are to continue profitable. The magnitude of this destruction is proved by the huge consumption of iron and steel pipe, tubing, casing, pump valves, and sucker rods to replace worn-out equipment, and by the amount of such equipment that is left in wells or junked. (See PI. I, A and B, and PI. II, A and B, and Fig. 14, p. 61.) This destruction of equipment constitu~es in itself a serious waste, but contingent production troubles, such as underground leakage of oil through defective tubing and pumps, and the consequent loss of oil and gas because of damage to pay sands by infiltrating water and silt, frequent and costly repairs with necessary suspension of production, and the ultimate injury to or loss of valuable wells, often cancel all operating profits. Many of these troubles result from rapid destruction of metal equipment by corrosive waters. The strata penetrated by the wells usually contain saline waters. Certain types of these waters, with their associated gases, are intensely corrosive; they attack well casing or tubing so vigorously as to riddle it with holes, rendering it useless in a few years or even a few months or weeks after it is installed. Pump plungers, working barrels, balls and seats of valves, and screen pipe, as well as lead lines and other surface equipment, are ruined with equal rapidity. The development and application of practical methods to retard or prevent this corrosion are among the most urgent problems of the oil and gas industry. Although much progress has been made in preventing the corrosion of metals, the need for reducing the damage from corrosion in oil and gas fields is still imperative. This is especially true of underground corrosion in the wells, because underground conditions favor corrosion and are difficult to study; hence they have not been thoroughly understood. In efforts to stop ~amage to oil and gas field equipment by corrosion, numerous methods have been proposed or tried with varying success. Some of these methods are cheap and effective. However, it is surprising that in many important fields the damage by corrosion is accepted as necessary or unavoidable, although cheap and effective methods that have been developed and successfully tried elsewhere might greatly reduce the trouble or eliminate it. This bulletin describes common causes and effects of oil and gas field corrosion and outlines methods of abating the damage. In order to accomplish this purpose best, the writer has avoided taking sides in controversies between the advocates of different metals for oil-field use; instead he describes the methods of combating corrosion in the various fields and suggests experiments that may yield valuable results. Throughout the paper he has freely used information from published reports of other investigators.

Jan 1, 1925

By Joseph A. Corgan

The river- or dredge-coal industry of Pennsylvania is conducted on many of the rivers and creeks that drain the Pennsylvania anthracite fields. Coal thus recovered found its way into the streams as coal was being prepared for market by the anthracite industry proper, in the northeastern part of the State. The Principal rivers draining; the fields, those where dredging is taking place, are the Susquehanna, Schuylkill, and Lehigh. Several creeks - the Shamokin, Mahanoy, Wiconisco, and Swatara - also are productive sources of river or creek coal. Operations along the streams cover a wide territory, and along the Susquchanna alone; dredges are recovering coal for about 160 miles. Anthracite was a significant factor in the early industrial development of the United States. Industry used it to generate steam, and railroads used it as fuel for locomotives; but it probably was most important industrially in the smelting of iron ore. For more than a hundred years homes have been heated with this fuel. From the beginning of mining in 1807, to 1940, more than 4 billion net tons of anthracite had been prepared and shipped to market. In the preparation process much of the smaller-size coal and refuse found their way into rivers and creeks which carried the material many miles. This study is concerned with the recovery of that anthracite from those rivers and creeks.

Jan 1, 1942

By Douglas W. Fuerstenau, Pradip Pradip

The design and development of selective flotation collectors has been the key to the remarkable success of flotation in beneficiating complex, difficult-to-process ores. Sustained research efforts in the field over the past hundred years have led to delineating the scientific basis of selective mineral flotation in terms of the crystal chemistry and the surface and colloid chemistry of minerals including their solubility, and the aqueous solution chemistry of added reagents. It is now well-established that the electrical double layer theory (EDL) is the most powerful means of quantifying the relative strength of mineral-reagent interactions in the case of nonsulfide minerals. We illustrate the utility and the power of the EDL in delineating the science underlying selective mineral flotation with the help of a few examples taken from our own work, in particular on the selective flotation of rare-earth minerals (bastnaesite) from associated semisoluble minerals (barite and calcite) using alkyl hydroxamate collectors and the flotation separation of lithium-containing minerals (spodumene) from associated alumino-silicate minerals with oleate (fatty acids). Both of these mineral separation systems are of contemporary research interest and of immense value to the industry today. Recent advances in utilizing molecular modeling computations, particularly in the context of quantifying the effect of crystal chemistry and the relative distribution of adsorption sites available on mineral cleavage planes, are also reviewed.

By A. Eltringham

Operations downstream of mining and beneficiation are still being subjected to increasing scrutiny as highly capitalized projects have been either slow to achieve their targets or have actually failed to do so. Leaching and smelting projects have fundamentally high calls on capital and technology as reaction rates are increased and the capture and disposal of unwanted products are subjected to greater restrictions. Separating value from waste inherently becomes riskier as the purification of the desired product imposes greater demands on the process to produce benign wastes. When we superimpose on the chemistry of the project severe predictions of throughput rates, that bring in facets of manufacturing, we are introducing complexities that the records show are not handled well. This paper discusses some of the more common challenges that operators face and what methods are available and are likely to be successful in preventing the loss of value as projects are brought on-stream. This thinking needs to start much earlier and at greater intensity than our industry has normally chosen to employ.

Jan 1, 2011

Law of the Sea. - The Ninth Session of the Law of the Sea Conference resumed July 28 at Geneva and will run for 5 weeks. The 160-nation Conference began in 1973. Two of the major factors to be discussed are the transfer of technology to the UN-controlled Enterprise or mining authority, and how the 36-member Council will make decisions. As the session completed its third week, delegates expressed little hope of completing a treaty text this year. There was a feeling, though, that substantive issues might be settled so that a treaty text can be completed next year. The Deep Seabed Hard Mineral Resources Act signed by the President on June 28, provides an interim regulatory procedure for ocean mining activities conducted by U.S. nationals that may be superseded by a law of the sea treaty.

Jan 1, 1980

By John I. Kasteler, John H. Hild

"INTRODUCTION The South Hecla mine, one of the principal mines of the Alta United Mines Co., is situated at Alta in thee Little Cottonwood mining district, about 30 miles southeasterly from Salt Lake City, Utah. The mine has produced copper, lead, zinc, gold, and silver, and is reported to have been one 'of the principal sources of this country's bismuth from 1912 to 1925. The tungsten mineral, scheelite, has been found but has not been recovered. The extreme need for these minerals during World War II prompted an examination of the property by the Bureau of Mines and resulted in an unpublished report entitled ""The South Hecla Mine, Salt Lake County, Utah"" (fig. 1).A Bureau of Mines project 3301 was initiated, and operations were started early in 1943. The primary purpose of the project was to increase substantially the reserves of bismuth and tungsten ores. The critical situation in regard to lead, copper, and zinc developed during the early stages of the operation, and the work was expanded to include the development of ores 'of these metals.An investigation of 'the Albion, Rustler, and Greeley workings adjoining the South Hecla mine was made, and this work is also described (fig. 2); ACKNOWLEDGEMENTSIn Its program of investigation of mineral deposits, the Bureau of Mines has as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution to national security and economy. It is the policy of the Bureau to publish the facts developed by each investigative project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual investigative work, and prepares the final report. The Metallurgical Branch, O. C. Ralston, chief, analyzes samples and performs beneficiation tests."

Jan 1, 1948

By Karl J. C. Harries

Mineral Agreements and Royalties

Jan 1, 2003

By C. H. Schack

Extractive metallurgy techniques currently employed to recover silver from primary ores and secondary scrap were reviewed and evaluated to identify and delineate metallurgical problems whose resolution would increase the supply of silver from domestic materials. The survey revealed that practically all primary silver is recovered by froth flotation concentration of various types of ores, followed by smelting and refining of the separate lead, copper, and zinc concentrates. Silver losses during the complex processing are, with rare exception, inconsequential. Furthermore, any silver production gain from base metal ores, which contribute about two-thirds of the total primary silver, is directly dependent no improvement in the market for the base metals. Statistical data on new and old silver scrap are wholly inadequate to make reliable conclusions about scrap processing problems and the possibility of increasing the recovery of silver from the many forms of secondary silver-bearing materials. The available information indicates (1) that efficient silver reclamation practices are employed by the larger users of silver, and (2) that recovery of additional secondary silver involves solution of problems of collection rather than of processing. Several possibilities exist for limited increases in silver production from primary ores by improvement in metallurgical practices. Specifically, research is needed to (1) solve the problem of recovering silver from the copper ores of the Copper Range district, Michigan; and (2) devise economically feasible methods for recovery of silver from presently marginal or submarginal ores char because of grade, location, and frequently complex nature cannot presently be exploited by conventional techniques.

Jan 1, 1965

The first metal-mine accident-prevention course was prepared and published in 1942--45 as a series of seven miners' circulars (Nos. 51-57). The scope of the course has been broadened, revised, and brought up to date, and it is being published as a similar series of seven miners' Circulars (Nos. 51-57, revised) on accident prevention in metal and nonmetallic mines. These circulars are: Accident Statistics (Miners' Circular 51), dealing with general statistics on accidents and injuries at metal and nonmetallic mines, including causes, costs, and the uses of investigations and reports of all accidents.

Jan 1, 1957

[RALPH ADAIR Ore Dressing Consultant Bull Mtn. Rd., Asheville, N. C. Phone 4-1693 JAMES A. BARR Consulting Engineer Mt. Pleasant, Tennessee Washington, D.C. BEHRE DOLBEAR & COMPANY Consulting Mining Engineers and Geologists It Broadway New York 4, N. Y. I. R. BERENT Engineering Consultants and Contractors Mineral Exploration, Mine Evaluation, Mine Designs and Mine Management 156, Ataturk Bulvari-Ankara, Turkey BLANDFORD C. BURGESS Registered Professional Engineer Mining Consultant Monticello, Georgia GLENVILLE A. COLLINS Mining Engineer Uranium examinations Cable "Coins" 8 Howard-Canfleld Bldg. Santa Barbara, Calif. COWIN & CO. Mining Engineers and Contractors Consulting Shaft & Slope Sinking Appraisal Mine Development Reports Mine Plant Construction I-lath St. S. W. B'ham, Ala., Phone 56-5566 MILTON H. FIES Consulting Engineer Rooms 1201-2. Albama Power Co. Bldg. Birmingham, Alabama]

Jan 1, 1952

By L Semenyna, W Douglas

Gold is often present in solid solution with pyrite in the Carlin Trend. The presence of organic carbon along with gold hosted in sulfide, referred to as double refractory ore, requires that ore with high carbon-in-leach (CIL) preg-robbing potential and poor leach recovery is routed to a roaster. During roasting, the pyrite is oxidised to (ideally) form hematite (Fe2O3), and the gold that was present as solid solution in the pyrite forms colloids within the hematite. The ideal texture of the produced hematite is porous to allow for the penetration of cyanide for gold dissolution. Temperature and other conditions of roasting, as well as ore characteristics (pyrite mineral associations, arsenic) can affect the texture and the type of iron oxide formed. Many of these alternate iron oxide minerals result in incomplete leaching. Comprehensive gold deportment studies have proven that the majority of the gold losses in Barrick GoldstrikeÆs roaster leach tailings occur within the iron oxides created through the roasting process.The iron oxide phase that hosts the majority of the gold in tailings is in the form of by-product maghemite (?Fe2O3), which is highly magnetic. Barrick Goldstrike has designed a magnetic recovery circuit to capture these iron oxides, and with subsequent reprocessing, recover the lost gold. Pilot plant results and analysis using scanning electron microscope mineral liberation analyser (SEM MLA) shows that up to 30 per cent of the gold in tailings can be recovered with a three per cent overall mass pull to magnetic concentrate. This magnetic concentrate can be economically reprocessed, resulting in a three per cent improvement in roaster recovery.CITATION:Douglas, W and Semenyna, L, 2013. Magnetic recovery of gold-bearing iron oxides at Barrick GoldstrikeÆs roaster, in Proceedings World Gold 2013 , pp 79-86 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By EDWARD B. DURHAH

(San Francisco Meeting, UCtober, 1911.) THE refinery at the San Francisco Mint takes the bullion purchased by the receiving department, and carrying more than 200 parts of precious metals in 1000, or, in mint parlance; over 200 fine, and separates and refines the various metals contained therein, using electrolytic processes exclusively. Bullion containing silver is treated in cells charged with a nitric electrolyte. These cells produce fine silver and leave a residue rich in gold. The residue from the silver-cells, together with crude gold-bullion, is treated in cells having a chloride electrolyte. These produce fine gold and leave a residue containing silver chloride. The latter is reduced to the metallic state with zinc and is then treated in the silver-cells. The various waste solutions and the wash-waters, after being freed from the bulk of their precious metals, still contain copper and other metals. These are removed by scrap-iron, and are then treated in the copper-cells, having a sulphate electrolyte. These cells produce pure copper, and collect a residue containing lead, some gold and silver, and all the metals of the platinum group that were in the bullion. This residue is relatively small, and is melted into bars and stored until sufficient accumulates to warrant treating it for platinum, etc. The refinery occupies three large and three small rooms. The large ones are, a melting-room, 30 by 34 ft.; a cell-room, 39 by 46 ft.; and a wash-room, 30 by 33 ft. The small rooms are used as foreman's office, laboratory, and generator-room, respectively. The methods here described are those in use in December, 1909, when notes for the present paper were taken.

Oct 1, 1911

By Robert S. Hill

"In November 1942, a preliminary report on the Swartz Mining District by John H. Soule, an engineer of the Bureau of Mines, recommended an exploratory program of diamond drilling. The existence of zinc and lead deposits in this region had been known for many years. In 1943 and 1944, the Federal Geological Survey made a detailed study of the same area. Later work done by the Bureau of Mines in this district followed the suggestions made by these geologists.3/In the latter part of 1944, Felix A. Vogel, Jr., another Bureau engineer, made a study of the Grey Eagle mine in the Kingston Mining District, a few miles northeast of the Swartz district, and his recommendations for diamond drilling were followed in so far as funds permitted. Drilling was started in October 1943 and was completed in June 1945.4/In its program of exploration of Mineral deposits, the .Bureau of Mines 'Ms as its primary objective the more effective utilization of our mineral resources to the end that they make the greatest possible contribution t national security and economy. It is the policy of the Bureau to publish the facts developed by each exploratory project as soon as practicable after its conclusion. The Mining Branch, Lowell B. Moon, chief, conducts preliminary examinations, performs the actual exploratory work, and prepares the final report. The Metallurgical Branch, R. G. Knickerbocker, chief, analyzes samples of ore and performs beneficiation tests. Both these branches are under the supervision of Dr. R. S. Dean, assistant director.With respect to this report, special acknowledgment for assistance is due to C. H. Johnson, chief of the Rolla Division, Mining Branch, and to various members of the Geological Survey."

Sep 1, 1946

By Byron S. Kutscher

This report summarizes the program to develop and construct an improved light-scattering dust monitor (ILSDM). This improved light-scattering dust monitor, which operates on the forward light scattering principle, provides instantaneous measurements of airborne dust concentrations in units of mg/m. The program was divided into two phases. Phase I involved the design of the ILSDM which was reviewed by the Bureau of Mines. Phase II included the fabrication of a prototype ILSDM based upon the design developed during Phase I. After completion, the ILSDM was delivered and demonstrated at the Bureau of Mines. A description of the final ILSDM design, operating instructions, maintenance instructions and recommendations for additional work are also included in this report.

Jan 1, 1980

By Karl J. C. Harries

"10.1. INTRODUCTIONDefinitions are a necessary part of every agreement. Their purposes are to assist the reader in reading and understanding an agreement and to attempt to avert potential confusion and, therefore, disputes. In some circumstances, they may be critical in deciding a dispute. As they are often substantive, they should not be treated lightly.It is far easier and less confusing for a reader to read “the Company” or “the Recipient” than to be faced with “the party of the First Part”, or to see the “Jones Property” than “that part of the property hereinbefore described in paragraph 1.01 hereof”. It is also advisable not to use “-ee” and “- or”, as in payee and payor.One thing must always be remembered: once a word has been defined in an agreement, it will always have the defined meaning unless the contrary is clearly indicated or is required to make sense of a provision.2 It can be confusing for a reader if commonly used words are defined in other than ordinary terms. Unique words that will stand out in the text are more likely to be recognized as having special meaning. It is also good practice to identify defined terms by capitalizing them in the text of the agreement. Boldfacing of definitions is also sometimes used for this purpose but, as boldfacing is not easily identified in handwritten revisions, it can be missed in the press of negotiations, especially when several typists are involved. Lack of consistency in identifying defined terms is not a fatal mistake, but it can create confusion, especially if the reader is new to the agreement or is reading it in a highly technical manner, such as when there is a dispute.If definitions used in the main text also apply to a schedule, they need not be included in both. Omitting them from the schedule makes the agreement look shorter, which to some people is a benefit. If definitions are not repeated, make certain that the schedule clearly indicates that words defined in the main text have the same defined meanings in the schedule3 and are clearly identified as defined words. In considering whether or not to repeat in a royalty schedule definitions appearing in the agreement proper, think of definitions as an aid and a reminder to the reader. Repeating them will help a reader, if only by saving the nuisance of remembering where to find them in the main text and constantly turning to it. All the definitions needed to read the schedule will be right there, so that the schedule is a self-contained document. Just make certain that, if you do repeat a definition, you repeat it in identical terms. If you have to change any defined term to make it fit the royalty provisions, use a different word or phrase as the defined term to warn the reader that he is dealing with a different concept.4"

Jan 1, 2003

By Christopher Mark

"Many problems in rock mechanics are limited by our imperfect knowledge of the material properties and failure mechanics of rock masses. Mining problems are somewhat unique, however, in that plenty of real world experience is generally available and can be turned into valuable experimental data. Every pillar that is developed, or stope that is mined, represents a full-scale test of a rock mechanics design. By harvesting these data, and then using the appropriate statistical techniques to interpret them, mining engineers have developed powerful design techniques that are widely used around the world. Successful empirical methods are readily accepted because they are simple, transparent, practical, and firmly tethered to reality.The author has been intimately associated with empirical design for his entire career. But where his past papers have described the application of individual techniques to specific problems, the focus of this paper is the process used to develop a successful empirical method. A six-stage process is described:1. Identification of the problem, and of the end users of the final product2. Development of a conceptual rock mechanics model, and identification of the key parameters in that model3. Identification of measures for each of the key parameters, and the development of new measures (such as rating scales) where necessary4. Data sources and data collection5. Statistical analysis6. Packaging of the final productEach of these stages has its own potential rewards and pitfalls, which will be illustrated by incidents from the author’s own experience. The ultimate goal of this paper is to provide a new and deeper appreciation for empirical techniques, as well as some guidelines and opportunities for future developers."

Jan 1, 2015