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By Carlos Soldi S

Dado que la industria minera adolece de técnicas para la administración y control de la fuerza laboral, es necesario que se plantee una nueva forma de mejorar el recurso humano en la productividad. En este sentido, el presente texto elabora un programa donde se analiza las pautas para el requerimiento del personal en la industria minera a través de la administración de la fuerza laboral, la determinación de requerimiento de personal, así como se evalúa la aplicación de estos factores mencionados en la unidad de producción de Casapalca, dada la expansión de las operaciones.

Nov 8, 1984

By Harold Paredes D

El presente texto señala el comportamiento químico de las principales impurezas de los iones metálicos y no metálicos provenientes de los efluentes líquidos de la industria minera durante el proceso de potabilizacion de agua. Es importante que el tratamiento aplicado a los micro u oligoelementos de dicha potabilización del agua, garanticen que los contenidos de sus concentraciones no sean nocivos para la salud, así como que la calidad del efluente líquido de las plantas de beneficio se corresponda a un bajo precio y garantice una óptima potabilización del agua.

Nov 8, 1984

By Elipio Pérez Coronado

El presente trabajo describe la aplicación del método de corte y relleno descendente mecanizado y el método de almacenamiento provisional en la mina Santa Bárbara, ubicada en Cerro de Pasco. Para el primer método, son mayores e intedependientes las operaciones unitarias, limitando la producción y generando mayores costos en el relleno chancado. Mientras que el segundo método, es aplicable en los cuerpos "Vasconia" y "Manuel", siempre que cumpla con tres condiciones principales que hacen posible su efectividad en la mina: la primera, señala que la explotación se realice en los pisos superiores y luego, en los inferiores; la segunda, refiere que la explotación son mayores las se haga en retirada y la tercera indica que el espacio no debe ser rellenado. En este sentido, el método de almacenamiento provisional resulta ser el más idóneo para la explotación de cuerpos irregulares en la mina Santa Bárbara puesto que su capacidad al término del acarreo de mineral es ilimitada.

Nov 8, 1984

By Mendoza F. Juan

En las últimas décadas, la minería subterránea ha optado por el uso del equipo mecanizado Trackless o minería sin rieles. Dado su alto costo, se ha previsto establecer un sistema de control que mida la productividad y así definir las causas de su bajo o alta rendimiento. En esta perspectiva, el presente trabajo señala el cálculo de probabilidades y uso del equipo en el interior y exterior de las unidades de producción de CENTROMIN-PERÚ, definiendo cada uno de los términos y determinando la fórmula de los cálculos para estructurar el sistema uniforme en la empresa.

Nov 8, 1984

By Manuel Cabrera M

El presente texto señala el uso del carbón como medio de concentración y recuperación de los metales preciosos. En este sentido, las posibilidades del carbón como medio de recuperación de valores metálicos de oro y plata son a través del carbón en pulpa, columnas en carbón y carbón en lixiviación-adsorción, las cuales tienen sus propias tecnologías y particularidades para cada mineral.

Nov 8, 1984

By Sergio Zúñiga S

El planeamiento de minado requiere de medios que aceleren el ritmo de explotación a través del transporte de trenes en la mina Cuajone. De acuerdo a estos tipos de carguío directo o por transferencia, el material a moverse se va incrementando. Por tal motivo, el texto señala programas que evalúen el rendimiento de los trenes, medir las distintas etapas de operación de los mismos y definir su utilidad en este proceso.

Nov 8, 1984

By M. H. Thomas

El presente trabajo describe tres ejemplos de empresas en Australia que utilizaron carbones provenientes de fuentes locales para el encendido de sus hornos. Así también se muestra los principios generales de la operación de los hornos rotatorios, la quema de combustible pulverizado, el encendido directo e indirecto, la contaminación de cenizas y los problemas derivados de la eliminación de azufre.

Nov 1, 1984

By Luis Noval Noval García

El objetivo de la ventilación es desarrollar una atmósfera saludable, segura y apta para la realización del trabajo por parte del personal. En ese sentido, el presente texto señala los gases como problemas comunes presentados dentro del ambiente minero tales como asfixia por anoxia (caso de inhalación) intoxicación, envenenamiento y muerte (letal) e inflamación y explosión (Productos). Para eliminar estos riesgos se debe eliminar las causas a través de una buena ventilación. Asimismo, es necesario conocer las propiedades de los gases, disponer de equipos para detectar su presencia y procurar los medios para eliminarlos.

Sep 1, 1984

By Rapid Beton

La división minera de Herault (Francia) de la C.O.G.E.M.A. orienta su tipo de exploración minera hacia un relleno cimentado integral, fabricado a partir del material estéril recuperado de la mina. En ese sentido, el texto revisa las técnicas de diseño y fabricación que la sociedad RAPIDBETON durante ocho años desarrolla en la mina de Uranio de Lodeve, Francia. Así, el uso de relleno cementado integral en las labores mineras descendentes permite una explotación en terrenos difíciles, donde los métodos tradicionales no son adecuados por su baja productividad y su elevado costo.

Sep 1, 1984

By E. Muñiz H

El presente texto describe los explosivos utilizados en la minería subterránea desde la fase de desarrollo hasta la actualidad. Así, el primer explosivo usado para el arranque de rocas en minería fue la pólvora negra. Posteriormente sus aplicaciones se limitan a las actividades lúdicas y bélicas. Luego, se volvió a utlizar la polvóra en la minería hasta mediados del siglo XIX y actualmente las dinamitas sustituyeron a la pólvora negra, reduciendo costos y generando nuevas vías de comunicación

Sep 1, 1984

By Carlos Fernandez Herrera

Dada las características del plomo-plata como residuo de uno de los subproductos de la obtención del zinc, es necesario un tratamiento adecuado que no reduzca el costo de sus ingresos por comercialización. En ese sentido, el presente texto describe los tratamientos para la recuperación de los residuos de lixiviación de calcinas en Cajamarquilla a través de la lixiviación ácida clorurante y así determinar la influencia de las principales variables involucradas en el proceso.

May 1, 1984

By Geoff Moore

A fin de reducir los costos de operación de una planta concentradora, se debe seleccionar la capacidad de bombas de impulsión de pulpas, así como el material de su fabricación. En ese sentido, el presente trabajo describe las aplicaciones de bombas para pulpas en plantas concentradoras, donde las tuberías son cortas como sucede en las bombas alimentadoras de hidrociclones.

May 1, 1984

By Samuel Canchaya M.

El presente trabajo señala los diferentes métodos geoestadísticos utilizados en la industría minera. Por ello, las aplicaciones de la geoestadística abarcan todas las fases de un proyecto minero que va desde la prospección hasta el tratamiento metalúrgico. Asimismo, los métodos geoestadísticos por su rigidez matemática, objetividad y eficiencia varias veces demostrada, pueden desplazar a los métodos tradicionales, cuyos errores e inexactitudes fueron poco advertidos en el pasado, debido a la bonanza y relativa accesibilidad de los depósitos minerales.

May 1, 1984

By M. H. Thomas

Ante la baja perspectiva en el aumento del petróleo, se replanteó el uso del combustible carbonáceo donde los beneficios económicos para cada usuario serán importantes, debido al costo considerablemente menor del carbón en comparación con los costos del petróleo. En ese sentido, el presente texto señala los factores económicos, costo de combustible, costo de capital para la central, factores políticos, la planta de combustión y manejo del carbón, generación de energía y las industrias del proceso para la revaloración de este combustible.

Mar 1, 1984

By Werner Ruegg

El presente texto describe algunos aspectos y propiedades de índole mineralógico, genético e individual de los diferentes yacimientos fosfatados. Existe una diversidad de fosfatos combinados como calcio, fluor, hierro, etc pero están aquellos también que son usados para fertilizantes limitados a los fosfatos cálcicos. De éstos, la apatita es su forma cristalina primaria, constituyéndose como la fuente de combinaciones. La fosforita, a su vez, es su contraparte amorfa, que establece un precipitado químico o un residuo orgánico donde existen combinaciones entre los dos.

Mar 1, 1984

By Mauricio Pero Diez de Medina

El presente texto describe los principales yacimientos de azufre contenidos en el departamento de Potosí, Bolivia. Las zonas auríferas se caracterizan por una serie de volcanes extinguidos que sobresalen del altiplano, donde existen lagunas y fuentes de aguas termales. A nivel regional se distinguen tres zonas: lava superior, zona piroclástica y lava inferior. Asimismo, la explotación, refinación y comercialización del azufre está a cargo de la Corporación del Seguro Social Militar (COSSMIL), del Grupo Barrero, del Grupo Clavija y en menor escala de las Cooperativas Mineras.

Mar 1, 1984

By Juan Carlos Ramirez

Durante mucho tiempo, los materiales arcillosos se resistieron a los métodos clásicos del análisis químico. Sin embargo, el análisis de la cristaloquímica y análisis térmico señalan nuevas perspectivas sobre la naturaleza de estos alumino-silicatos. En ese sentido, el presente texto refiere la clasificación de dichos materiales basados en la similitud del comportamiento plástico y la estructura química. Así también se revelan sus propiedades importantes como contenido de humedad, color y textura, fluidez y defloculación, resistencia, sílice libre, sales solubles, fierro y carbono, respuesta térmica y la producción y consumo.

Mar 1, 1984

By James W. Stewart, A. C. Colvine

Introduction Precambrian shield terrains the world over are experiencing an unprecedented level of concerted exploration for lode gold deposits. Reasons for this include: • The increase in the price of gold (following 40 years at $1.13/g or $35 per oz) has transformed targets that were once unattractive into viable exploration propositions. • The relatively suppressed market for other metals produced from shields (base metals, nickel, iron, and uranium) has further focused exploration attention on gold. • The preeminence of gold production from rocks of early Precambrian age, as shown in Fig. 1. • The relatively high grade of gold in these mines (averaging about 10 Wt or 0.29 oz per st) permits profitable extraction even under depressed gold prices. A number of these mines have been in continuous operation for more than 50 years. • The recent discovery of the major Hemlo deposit, in well exposed rocks adjacent to the Trans Canada Highway, has had a world-wide impact. This demonstrates that a major new deposit can be found even in an accessible, well exposed area of a shield; gold mineralization is susceptible to rational exploration; and new target types for gold exploration exist. This paper reviews exploration activity for gold in shield terrains worldwide (Fig. 2), excluding Early Proterozoic paleoplacers of the Witwatersrand type. Emphasis is on the Archean, which is traditionally the most productive part of the Precambrian shields. There is also an emphasis on the Canadian shield (Fig. 3) because of its vast areal extent and exceptionally broad range of mineralization styles. Geological Approach A basic problem exists in gold exploration when compared to exploration for base metal massive sulfides that predominated during the 1960s and 1970s. Gold concentrations cannot usually be detected by airborne geophysical instruments. The majority of massive sulfide deposits were detected using airborne electromagnetic detectors and magnetometers. A full 75% of Canadian gold discoveries can be credited to surface prospecting. The percentage is even higher in other countries. This observation allows for great optimism for two reasons: • Large areas of shield terrain are obscured by either surficial deposits (glacial tills, clays, and desert sands) or deep surface weathering. This makes them inaccessible to prospectors. Logic dictates that such obscured areas should have the same potential for gold concentration as has exposed bedrock. • The Hemlo style of mineralization, a roughly tabular ore body where gold is associated with disseminated sulfides, is different from the traditional prospecting target. The gold is hosted by discrete quartz veins. While it is true that limited discoveries were made at Hemlo more than 30 years ago, and this style of mineralization is present elsewhere, recent

Jan 12, 1984

By E. C. Robertson

D.G. Wilder I found the suggestion that the amount of displacement of a fault can be numerically related to the thickness of gouge or breccia to be both intuitively satisfying and intriguing. I have long agreed that there is some type of relationship between the amount of gouge and the amount of displacement of faults. I congratulate the author for developing a numerical relationship between them. However, I am concerned that the limits for applying this relationship be fully understood. An underlying assumption in this approach is that there is either a uniform thickness of gouge or breccia along a given fault or the thickness does not vary widely. Since it is not always possible to confirm this, the displacements derived by this method should be viewed with caution unless significant fault extent can be observed. At the Nevada Test Site, in drifts constructed in granite for test emplacement of spent nuclear reactor fuel, we found a fault with 0.3 to 0.4 m (12 to 16 in.) of clay gouge. Within a few meters of this location, the fault had no clay gouge, but rather consisted of a highly fractured zone with significantly altered rock and some slickensides. Based on Fig. 1, the 0.3 to 0.4 m (12 to 16 in.) thickness of gouge would indicate a displacement in excess of 30 m (98 ft). However, no gouge thickness would indicate essentially no displacement. Based on a quartz vein that terminated on the fault, and is not identified nearby, an estimated displacement of more than a few meters was made. This estimate is consistent with that obtained using the regression line proposed in the paper if the 0.3 to 0.4 m (12 to 16 in.) thickness for the gouge is used. However, using the regression curves with zero thickness would not yield results consistent with what was observed in the field. Therefore, it is important to recognize that the suggested procedure would properly yield a range of probable displacements. ? *Work performed under the auspices of the US Department of Energy by the Lawrence Livermore National Laboratory under Contract W-7405-Eng-48. Reply by E.C. Robertson It is certainly true that the t (thickness) of gg-bx (gouge and breccia) on a fault does vary along the fault. My observations have been that near the termination of a fault, the displacement d is small and the t is also small, whereas the maximum d and t will usually be found in the central part of the fault. The information on gg-bx and t of the fault found in granite in the NTS tunnel by Mr. Wilder could be interpreted somewhat differently than he does. He speaks of the fault changing within a few meters from 0.3 to 0.4 m (12 to 16 in.) of clay gg to "a highly fractured zone with significantly altered rock and some slickensides," but no gg. The highly fractured rock may be taken to be bx, rock not so finely ground as gg but still crushed by the fault movement, equivalent to the gg in my usage, and probably occupying about the same t. Mr. Wilder's estimates for the fault in the NTS tunnel for t of 0.3 to 0.4 m (12 to 16 in.) and for d of a quartz vein, in excess of "a few meters," would place the point on the low side of the central trend line in my Fig. 1, at the lower limit. There is, of course, a problem with determining d using displacement of only one planar surface. It would be greater or lesser depending on the rake of the movement. Finally, estimating the d of a fault from its t should be made with awareness of our present uncertainties, as pointed out by Mr. Wilder. Although the central trend line in my Fig. 1 has a ratio of d/t of 100, I have put the limiting ratios at 10 and 1000. Understanding of the values of the ratio will be improved only with collection of more data, for which the discussion of Mr. Wilder is much appreciated. G.C. Waterman E.C. Robertson's paper provides significant information to a geologist attempting to deduce fault offset by noting the products of structural dislocation. However, considerable mapping in underground and open-pit mines, and examination of structures produced in different geological settings, have convinced me that gouge and breccia thickness are controlled by geological conditions and fault movement. The following paragraphs suggest geological variables that control them. 1. Depth of Loading A near-surface fault resulting from tensional stress has more breccia/gouge than is produced by a similar stress at considerable depth. A deep-loaded compressional stress may produce a linear zone of schist, or structural dislocation may occur along an earlier formed belt of schist. Such "shear zones" are common in Canadian mines in precambrian rocks. In neither case can offset be directly deduced by an analysis of the minimal gouge/breccia in the shistose rocks. At greater depth, stress may be partially to wholly relieved by flowage. I vividly recall first noting the regional "Midas Thrust" in the Lark mine, Bingham Mining District, UT (where we called the structure the North Fault). My recorded notes, as I remember them, showed a narrow gouge streak separated the `Jordan" and "Commercial" limestone units from impure, muddy limestone beds of uncertain stratigraphic position. The visible structure did not indicate the great importance of this premineral fault

Jan 12, 1984

By Richard L. Nielsen

Early Models In 1906, Daniel Jackling demonstrated that relatively low-grade disseminated copper deposits could be mined profitably using mass mining technology. The ensuing years saw a gradual increase in activity aimed at defining ore targets for large reserves of disseminated supergene enriched copper ores. Prominent organizations, such as Calumet and Hecla, Phelps Dodge, and Asarco, established teams of geologists. They focused on interpreting oxidized and leached outcrops over supergene chalcocite ore bodies. Techniques to evaluate oxidized cappings and predict the presence of underlying supergene chalcocite enrichment ores were developed and put to practical use by the late 1920s and early 1930s (Locke, 1926; Blanchard 1939, 1968). Oxidized capping evaluation centered on recognizing oxidation products derived from the various sulfide minerals found in disseminated deposits. Chalcopyrite, for example, oxidizes to a characteristic reddish pitch limonite that exhibits characteristic boxworks. Chalcocite is recognized by earthy, powdery, indigenous, hematite-rich limonite. Pyrite weathers to characteristic cavities and yellowish jarositic limonites. Evaluation of cappings is a systematic effort of noting and estimating the preoxidation sulfide mineral content and copper grade in an oxidized outcrop using mineral composition and morphology of oxidation products. Several complications were noted early in this technology's development. For example, the associated pyrite content of protore greatly influences mobility of copper and iron during oxidation. High-pyrite disseminated sulfide assemblages, upon oxidation, mobilize iron as well as copper. This results in oxidized rock with many leached cavities, poorly developed boxworks, and poorly developed indigenous limonites. This effect was noted and used in a general way to identify possible development of supergene chalcocite. Indeed, strongly leached outcrops could be present over enriched ore. A second complication is the manner in which associated gangue minerals influence the products of sulfide oxidation. Reactive gangue minerals, such as carbonates, neutralize acids formed by sulfide oxidation. Thus, copper cannot be moved from oxidized outcrops. Relatively nonreactive gangue, such as quartz-sericite-altered schist or porphyry, neutralizes supergene acid very slowly. This allows copper to move out of the oxidized outcrop. Recognizing these features was closely allied to an early understanding of the processes involved in oxidation supergene enrichment of disseminated ores. Field observations and mineralogic mapping of oxidized cappings were important in discovering many important porphyry copper ore bodies during the 1920s. These include Silver Bell, Miami-Inspiration, and Morenci in Arizona; Tyrone, NM; and Ely, NV. Capping interpretation like-wise led to discoveries at Mineral Park and Esperanza in Arizona during the exploration surge that accompanied high copper prices in the 1950s. In the 1960s, Kennecott research geologists refined and quantified some aspects of oxide capping appraisal (Anderson, 1982). The ratio of jarosite plus hematite to the total limonite assemblage was shown to be proportional to amount of copper leached from the oxidized outcrop. Thus, if the limonite assemblege in an oxidized capping consists of 40% goethite, 20% jarosite, and 40% hematite, 60% of the original copper is leached. The amount of copper remaining in the capping, together with the limonite mineralogy, can then be used to estimate original copper grade in the outcrop, amount of leaching, and chalcocite enrichment grade (in feet/% copper) in the underlying supergene chalcocite zone (Anderson, 1982). Evaluation of oxidized cappings and prediction of chalcocite blanket ore targets were successfully used in the western US and South America through the 1950s. Discovery of new porphyry copper provinces in other regions during the 1950s and 1960s, however, underscored some limitations of capping evaluation technology. Porphyry copper systems in Australia generally oxidize and weather to hematitic cappings. Presumably, the semiarid monsoon environment and the long time that the sulfide systems have been exposed to oxidation on that continent lead to development of relatively stable hematite. It is now recognized that jarosite and goethite persist metastably in the limonite assemblage in all areas once sulfide oxidation is complete and acid generation ceases (Brown, 1971). The assemblage eventually converts to hematite. But, climatic conditions in arid southwest US allows metastable limonites to persist for a long time, thus providing information on former sulfide assemblages. Another problem occurs when applying capping evaluation techniques in extremely humid re-

Jan 12, 1984