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By R. A. Busch

Sludge ponds of fine coal, fine soil, and water created behind large piles of coarse coal waste can present hazardous conditions; this is a Bureau of Mines report of the subsurface physical property data developed on the fine coal waste materials that make up the core areas of two typical coal waste impoundments. These data will help define more completely the engineering properties of this problem area of the structures. Additional calorific, chemical, and mineralogical data were obtained on the coal waste materials to determine possible uses or development of byproducts. The possibility of extracting alumina from coal ash was also investigated.

Jan 1, 1975

By C. B. Daellenbach

A prototype particulate size analyzer system was developed that would rapidly determine size distributions of homogeneous and two-mineral materials in the 74-micrometer (200-mesh) to 7-micrometer size range. The system sizes particles in a series of hydrocyclone elutriation steps and senses the weight of the five sized fractions by nuclear attenuation techniques. Size distribution of materials was determined from experimentally developed mathematical relationships that existed between particulate weight and the measured transmittance of gamma rays from an Americium-241 source. In the developmental phases, size distributions of three minerals (quartz, magnetite, and hematite) and a laboratory prepared two-mineral mixture of quartz and magnetite were accurately determined by the prototype system. In later stages of the investigation, semiconcentrates, an intermediate magnetic product from a taconite plant, were evaluated. Using 25-gram feed samples of this industrial material, the analyzer system was found to predict weight percentages for individual size fractions with an accuracy of ±0.85 percent or better at a 95-percent confidence level.

Jan 1, 1974

By R. J. Caro

The Anaconda phosphate plant was put into operation in the fall of 1923. Its present daily operating capacity is approximately 170 tons of treble superphosphate and 16 tons of phosphoric acid analyzing 42 pct P2 O5 and 52 pct P2 Os, respectively. As a result of the continued increased demand for phosphates, Anaconda decided in 1947 to expand the plant's daily output to 270 tons of treble superphosphate and 54 tons of phosphoric acid. The present daily plant intake is 335 tons of wet (footwall) phosphate rock analyzing 31.7 pct P² O5 and 0.28 pct V² O5. The rock is shipped from Anaconda's mine at Conda, Idaho, in open railroad cars, having been crushed to pass 3/8 in. mesh at the mine.' The expansion program will require an increased intake of 300 tons of rock per day. The hanging-wall rock anaIj-ses approximately 30.5 pct P2 O5 and 0.11 pct V² O5, and will be beneficiated in a new washing plant under construction

Jan 1, 1950

By Joseph A. Holmes

(Pittsburg Meeting, March, 1910.) AT the Mining Experiment Station of the U. S. Geological Survey, in Pittsburg, an investigation of the process of combustion is being carried on in a specially-designed furnace having an unusually long combustion-chamber. This work is conducted by a committee consisting of H. Kreisinger, mechanical engineer; Dr. J. C. W. Frazer, chemist; and Dr. J. K. Clement, physicist. The problem, essentially one of physical chemistry, is extremely interesting to all who are concerned in the burning of coal or the construction of furnaces. The main object of these experiments is to ascertain the relation between the amount of the volatile combustible driven from the coal and the combustion-spaces necessary to burn it completely. Our best steam-coals vary from 15 to 45 per cent. of fixed combustible. The greater part of the latter is burned on the grate; but the volatile combustible leaves the freshly-charged coal and must be burned in the combustion-space. If this space is not large enough, the volatile combustible will leave the furnace only partly burned, and the result will be a considerable heat-loss and a smoky stack. Strictly speaking, the factor which determines the completeness of combustion of the volatile matter, after it has been mixed with a certain amount of air, is the length of time the mixture is allowed to remain in the combustion-space; but this length of time depends on the extent of the space itself. Let us suppose, for instance, that, when a given coal is burned at a certain standard rate, the volume of the volatile combustible driven off per second is 10 cu. ft. Adding, say, 10 cu. ft. of air, the volume of the resulting burning mixture is increased to 20 cu. ft. If the combustion-space is 20 cu. ft., the burning mixture will stay in it,

May 1, 1910

By Bianka Nani Venturelli

Estudou-se o efeito do tamanho de grão austenítico nas propriedades de tração do aço Hadfield refinado com Hf. Estas propriedades foram comparadas com as de um aço Hadfield sem refino, ambos com a composição química de acordo com a norma ASTM A128 – grau B2. Adicionalmente, foram usadas técnicas de caracterização macroestrutural, microestrutural e fractográfica. A caracterização macroestrutural mostrou que o aço Hadfield com adição de Hf apresentou tamanho do grão austenítico (600 ?m) aproximadamente cinco vezes menor do que o do aço Hadfield sem refino (3000 ?m). Os resultados do ensaio de tração mostraram um pequeno aumento (~6%) no valor do limite de escoamento com o refino do grão, em acordo com a Equação de Hall-Petch para materiais austeníticos. No entanto, os resultados dos ensaios de tração do aço Hadfield refinado mostraram aumentos que não foram previstos para as propriedades de resistência à tração (~37%), alongamento (~53%) e tenacidade (~88%). O exame fractográfico dos corpos de prova de tração indicou predominância do mecanismo de fratura dúctil para o aço Hadfield sem refino, enquanto que o aço Hadfield refinado apresentou predominância do mecanismo de fratura intergranular dúctil.

Oct 30, 2017

By Duah Philip, Awuah-Offei Kwame

Regulatory pressure to mitigate the cement industry’s environmental impact has intensified recently, spurring innovation in low-carbon cement technologies. In the United States, cement production, consumption, and carbon emissions are accelerating. Despite this trend, the adoption of environmentally friendly dry clinker production technology with combined preheater-precalciner systems has surged from 53.3% in 2002 to 88.5% in 2019. Concurrently, reliance on wet technologies, known for their higher environmental impact, has dropped from 16.5% to 0.6% within the same period. This paper presents the results of our comprehensive study, utilizing over 100 years of industry data, to analyze these technological shifts and their environmental implications.

Feb 1, 2025

By W. E. Bardelmeier

The high speed conveyor type self unloading bulk carrier concept has been around for about 70 years. Although the design was developed, refined and steadily improved in the Great Lakes, to date limited numbers of such vessels have emerged in the bulk ocean trades, and these have tended to concentrate within specific mineral trades. For example, North American gypsum companies have embraced conveyor self unloaders to the point where such vessels almost exclusively carry the gypsum requirements of this part of the world. One major aluminum company has developed an impressive fleet capability in self unloaders. Application of other ships tends to be fragmented through several mineral trades. A few years ago a new phenomonen began to appear on the Great Lakes. Whereas it had historically been accepted in that region that self unloaders were effective vessels for the minor bulk trades including limestone, coal, salt, gravel and sand; they had seldom been employed heavily in the big volume iron ore trades. Suddenly, however, the new generation of 60,000 ton Lakers which emerged were all designed as high speed self unloaders. The new vessels intended to trade especially in ore, or alternatively especially in coal, have somewhat different internal features, but the important point is that all are self unloaders.

Jan 1, 1979

By G. Fuentes, J. Viñals

"The nature and basic kinetics of the hydrothermal reactions of bornite, covellite pyrite and enargite with copper sulfate solutions were investigated, as a previous study on the behavior of the bulk Chilean copper concentrates. The reaction of bornite produced digenite at 160 °C and djurleite above this temperature. Covellite was transformed to digenite at < 200 °C and to chalcocite (Q and M) at > 200 °C. The pyrite reaction was significant at > 200 °C and extensive at 240 °C, enargite reacts only above 240°C and produces digenite. The hydrothermal treatment of Chilean Codelco-type copper concentrates with hydrothermal reactions was similar to those obtained from pure mineral samples.INTRODUCTIONStudies on the hydrothermal enrichment of chalcopyrite concentrates were begun by MacGauley and Roberts (1951), Roberts et al. (1953) and MacGauley and Schaufelberger (1956). In the 1970's these processes were reexamined by McKay et al. (1972), and Johnson and Coltrinari (1976), but it not was until the 1990s when the kinetics, mechanisms and full engineering aspects were studied by Barlett, (1992), Jang and Wadsworth, (1994) and Peterson and Wadsworth (1994). The main objectives were to solve some important problems in the copper pyrometallurgy: The increase of the smelting capacity, the reduction of the iron slag – and associated copper losses – as well as the reduction of sulfur emissions. The present rise in copper demand and price implies the production and subsequent treatment of very impure concentrates. Thus, a significant increase of environmental problems can be expected in the copper pyrometallurgy. The previous purification of concentrates can reduce the processing of wastes containing hazardous heavy metals in the copper refineries and the hydrothermal treatment can be an alternative which combines both enrichment and purification. On the other hand, Chuquicamatatype concentrates (Viñals et al., 2004a) contains digenite (Cu1.8S), pyrite (FeS2), chalcopyrite(CuFeS2), b ornite (Cu5FeS4), covellite (CuS) and sphalerite (ZnS) as the main mineral components, with minor amounts of enargite (Cu3AsS4), galena (PbS) and molybdenite (MoS2)."

Jan 1, 2012

By M. R. Geer Olds, H. F. Yancey

.I. S. Huckaba (Western Machinery Co., Spokane, Wash.)—It has been my pleasure and privilege to be able to follow this work with the H.M.S. pilot plant very closely. This has been a very thorough and painstaking piece of work and will be of great value to the dense-media operators and manufacturers. Unfortunately time was not available to make an accurate comparison between this pilot plant and the commercial plant at Bellingham Coal Mines, both plants having Wemco drum separators. Briefly I would like to point out what I consider the most interesting finding of this work. Capacity: Very good results were obtained at a feed mte of 5.2 tons per hr in a 30-in diam by 24-in. long drum separator. The maximum capacity of this drum is not known but it is something over 5.2 tons per hr for the available area of 2.08 sq ft. Medium Preparation: The importance of proper medium preparation is well demonstrated. A "tailored" or

Jan 1, 1954

By Kefton H. Teague

Olivine is a mineral containing a mixture of forsterite (Mg2SiO4) and fayalite (Fe2SiO4) in solid solution. The name olivine was first applied by Werner in 1790 (Hunter, 1941) because of the olive-green color of the mineral. Olivine is the principal component of the rock dunite, which itself is a member of the peridotite group of ultrabasic igneous rocks. European uses of the terms olivine and dunite are somewhat different than US usage. In commerce European usage defines dunite as containing 36 to 42% MgO, 36 to 39% SiO2, and loss on ignition of approximately 10%. The term olivine is used to designate a material containing approximately 85% forsterite, with a chemical composition of approximately 45 to 50% MgO, 40 to 43% Si02, 5 to 8% Fe2O3, and ignition loss of 1 to 2%. Uses The principal use of olivine is in various applications involving hot metal. Table I shows the best estimate available as to the amount of olivine consumed by various industries worldwide. In excess of 90% of world uses involve hot metal, with approximately 75% as a slag conditioner in the blast furnace production of pig iron. Approximately 15% of total olivine usage is as a special foundry sand in mold making for the brass, aluminum, magnesium, and manganese steel foundries (Schaller, 1957, 1958; Snyder, 1957; Anon., 1977). Olivine was first used as an industrial mineral in the early 1930s for a refractory material (Anon., 1970; Hunter, 1941). As a refractory raw material, olivine was first introduced in the United States as hand-cobbed, selected, shaped blocks of crude olivine. This use met with limited success. More recently, finely ground olivine blended with MgO and pressed into bricks, which are then fired, has found use in glass tank furnaces and open-hearth furnaces. Ramming or gunning mixes for basic furnace linings also utilize olivine. Olivine has been used in ladle linings with varied success. In Europe, substantial tonnages of olivine are utilized in refractory brick for night storage heaters (Anon., 1970). A limited amount of olivine has been used in the past as a fertilizer (magnesium source) and has been fused with rock phosphate to produce a magnesium phosphate as a plant food. The relatively high magnesia (MgO) content of olivine also attracted attention to it as a potential source of both magnesium compounds and as a source of metallic magnesium (Bengston, 1956; Hunter, 1941). The use of olivine as an additive in the blast furnace is relatively new, having been developed during the last decade. J.W. Currier (Private communication, 1978) describes the behavior of olivine in the blast furnace as follows: Olivine (Mg, Fe2, Si04) represents a unique lime-free source of magnesia and silica as a blast furnace charge component. Only recently has the magnesia-rich mineral been recognized as beneficial cleaner for blast furnace experiencing the problems associated with excessive alkali inputs and/or low coke stabilities. For some time it has been known that alkalis tend to recycle and accumulate in blast furnaces. In the high temperature region of volatilization the elemental alkalis formed attack the integrity of the graphite structure. This alkali attachment is enhanced when poor coke is used. Higher in the furnace stack volatile alkali cyanides condense and oxidize. This accumulation of alkalis tends to agglomerate the burden materials, producing scabs and scaffolds. These structures not only inhibit the downward movement of burden materials and the upward passage of wind, but also lead to erratic furnace performance

Jan 1, 1983

By Vanessa Viterbo, Lia Walker, Hassan Khaniani, Vitor Viterbo

Fatigue is a major contributor to haul-truck incidents in mining, with up to 65% of fatigue-related events associated with operator drowsiness or microsleep episodes, Williamson et al. (2011) and Caterpillar (2007). This study examines whether operator fatigue produces measurable and repeatable signatures in haul-truck telemetry. Eight confirmed fatigue-related disengagement events were analyzed using 20-minute telemetry windows centered around the incident. Statistical descriptors, Z-score normalization, first- and second-order derivatives, sliding-window variability, and cross-signal correlations were extracted from engine speed, throttle position, fuel rate, ground speed, and brake indicators. A logistic regression classifier was trained and evaluated using leave-one-event-out cross-validation. The model achieved a receiver operating characteristic (ROC) area under the curve (AUC) scores of 0.75–0.79, demonstrating consistent discriminative capability. A characteristic shutdown sequence characterized by sudden throttle collapse, fuel-rate decay, RPM reduction, and unbraked coasting was observed across all events, indicating operator disengagement rather than mechanical malfunction. Earlywarning indicators appeared 90–500 seconds before shutdown in the events analyzed, suggesting practical potential for real-time fatigue prediction. These findings provide initial evidence that telemetry-based fatigue detection is feasible and could enhance safety in mining operations.

Feb 22, 2026

By Jim Sundal

Primary steel manufacturers using electric arc furnaces generate one of the largest hazardous waste streams nationwide. The waste stream, known as electric arc furnace dust, is a listed hazardous waste with the designation K061. Oregon Steel Mills, Inc., (OSM) of Portland, Oregon, has implemented a process known as Glassificationn, which uses KO61 as an ingredient in an onsite recycling process. Because OSM was able to demonstrate that the Glassificationm recycling process beneficially uses all toxic constituents in the electric arc furnace dust and that the recycling process produces marketable products, the process is not subject to Resource Conservation and Recovery Act (RCRA) permit requirements. The marketable products manufactured using Glassificationn include roofing granules, ceramic glazes and colorants, abrasive blasting media and, more recently, synthetic slag fluidizers. The purpose of this paper is to identify the regulatory issues for recycling hazardous waste and demonstrate that OSM glass frit is effective as a slag fluidizer in primary steel manufacturing.

Jan 1, 1994

By Thomas A. Gwynn

When Lewis and Clark first pushed their boats up the Missouri River, Meriwether Lewis reported the presence of coal in the western states by saying in 1802 that it "burnt tolerably well and afforded but little flame or smoke but produced a hot and lasting fire". Lewis would have been amazed and bewildered at the history of coal development in this region and the more recent political-socio-economic-environmental confrontations of today. Certainly without this coal the railroads would not have readily pushed into our western states, and the progress of this region would have suffered. The coal industry has passed from a period when "coal was king" to a period of depression in the industry, but its importance is being revived. A contributing and simultaneous environmental concern has emerged in the nation and in many states during the past ten years, partly caused by newly imposed standards for sulfur content of fuels. Much of the midwest and eastern coal cannot be used because of high sulfur content, shifting attention to the low sulfur coal deposits of the western states. In the western states, lands disturbed by strip mining or even underlain by strippable coal are small compared to the total acreage, and usually mining operations are on lands not under cultivation. There are some farm lands being disturbed by surface mining, but this is often over-emphasized. In states like New Mexico and Arizona the percentage is less. The value of the minerals underlying the surface certainly must be considered along with the value of the surface, and sometimes proper reclamation following mining can result in higher ultimate usage of the land.

Jan 1, 1974

By V. Silins, J. Tameling, R. C. Cook

"A general review of the wear problems encountered in the mining industry is presented and current practice for wear protection systems is reviewed.A new concept in wear protection is described and compared to alternative systems. Utilization of conventional stud welding technology and abrasion-resistant wear studs is shown to be a useful supplement or substitution for conventional techniques. Operating life of many consumable components can be increased by up to four fold. The technique is highly portable for on-site field application or can be used in shop environments.Details of the wear protection model and metallurgical properties of the wear component are also reviewed. Laboratory wear test data are reported to supplement field test performance or to screen potential alloy compositions for application in specific environments.A Review of Wear Problems and Wear ProtectionThe emphasis on wear protection has increased in recent years because of the increasing impact of the potential savings in time, materials and energy. A 1974 German study concluded that attention to tribology, the study of friction and wear, could save approximately $3 billion, and a study in the U.S.A. at the same time put the figure at $100 billion of which $20 billion was for materials. A more recent American study put the energy component of the potential savings at $16.2 billion per year. A recent British study estimated the total potential savings in the U.K. as $1 billion per year, with the largest savings coming from lower maintenance and replacement costs ($500 million), lower breakdown costs ($250 million) and increased machinery life ($200 million). These three major contributions are all potentially accessible in the mining industry."

Jan 1, 1982

By Robert S. Williams

On several occasions, when 60-40 brass is first obtained in the beta condition by quenching at about 825" C. and is then reheated, the writers have noticed that reerystallization will take place in the form of twin crystals at the grain boundaries of the original beta crystals. It was, therefore, thought that interesting results would be obtained if this twinning process was studied further, especially as to the temperature at which it first occurs. The material used in the investigation was a bar of extruded muntz metal, 1/2 in. in diameter, and of the following composition: Copper, 60.21 per cent.; zinc, 39.73 per cent.; lead, trace; iron, trace; tin, nil. Specimens 1 in. in length were sawed from this bar and a hole was drilled into the side of each specimen until it reached the center, and the tip of a platinum-platinum rhodium thermocouple was inserted. A small Hoskins&apos; resistance-type electric furnace was used for heating the specimens. The specimens were first heated at 840&apos; C. for 2 hr. and then quenched &apos; in cold water, in order to get the material entirely in the beta state. In every case, in the reheating process, the furnace was brought to the desired temperature before the specimen was introduced. The time occupied in preheating was from 20 to 30 min. By sawing back 1/4 in. on each side of the hole, two parts were obtained from each specimen and duplicate observations were possible. The specimens were held at the reheating temperatures for periods of 15 min., 30 min., 1, 2, and 4 hr. All specimens were etched with a freshly prepared mixture of equal volumes of concentrated NH4IOH and H2O2.

Jan 1, 1924

By K H. Esbensen

Optimisation of a real-time at-line monitoring system for control of industrial granule coating quality is presented. The system is based on a fluorescence imaging system, because fluorescence originates in the interiors of enzyme granules but is significantly quenched by a polymer coating (which is needed due to environmental precautions). We have developed an image analytical system for direct prediction of coating quality, which is based on application of the Angle Measure Technique (AMT) for image complexity characterisation; AMT is briefly described. The first part of the presentation addresses pixel sampling strategies within a digital industrial image, inherent in application of AMT, in which the unfolded image is regarded as a one-dimensional object in analogy with 1D process sampling in Theory of Sampling (TOS). The effects of random, stratified and systematic pixel selections in the unfolded image are evaluated. Also factors such as the fraction of image pixels and the effects of specific unfolding strategies (there are three principal strategies, termed æchopÆ, æsnakeÆ and æspiralÆ respectively) are investigated. It turns out that unsuspected artifacts are sometimes produced, related to the specifics of the unfolding procedure, which interferes with a straightforward 1D TOS process sampling analogy. These artifacts have a wider interest û among others, for 2D sampling û and therefore receive special attention in this presentation. The optimal pixel selection strategy for the AMT algorithm is found to be systematic or stratified sampling (not surprising according to TOS) of 500+ initiating points, but need to be unfolded in the novel spiral- or snake-wise fashions in order to effectively counteract these artifacts. This also has a general impact on various suggested standard schemes for 2D grid-sampling, among others, from the geoscience realms. The second part of the presentation is directed towards optimal image analytical sampling of a continuous series of fluorescent images (imaging of conveyor belts of æinfinite lengthÆ), ie optimisation of process image sampling. The minimum number of images needed to uphold a sufficiently good on-line estimate of the quality control (QC) parameter in question is found to correspond to the relatively high sampling rate of 15 - 20 per cent, which can be shown to be related to an intrinsic very high measurement error level (25 per cent) of a mandated analytical reference method.

Jan 1, 2005

By D Pateman, F de Fredrick

The Bentley underground mine, which is located 60km north of Leonora, Western Australia, is owned and operated by Round Oak Minerals Pty Limited. A high-grade Zn-Cu Volcanogenic Massive Sulphide (VMS) orebody, Bentley was discovered in 2008 with production commencing in 2012. Long-hole open stoping is employed to mine the steeply dipping ore body, and in recent years the Avoca method has been adopted. This requires all development in a particular area of the mine to be completed prior to stoping commencing in a bottom up sequence. Voids are commonly backfilled with loose Run-of-Mine (ROM) waste loose rockfill (LRF); or alternatively cemented rockfill (CRF) can be used. Stopes in the 3860 AOS and 3900 AOS panels were located below previously extracted Avoca zones, with LRF situated immediately above them. These high-grade stopes were originally designed with rib and sill pillars to maintain control of the existing backfill during extraction. Due to changing factors over time, including mining economics, alternative options to achieve full extraction of the stopes were reviewed, including: • Mining small successive full height stopes which would involve drawing a blanket of LRF down with the extracted ore (stoping under waste); • Stabilisation of the existing LRF above the stopes and implementing a primary/secondary stoping sequence, with the primary stopes backfilled using a cement fill. An assessment of these options was undertaken which determined that the second full extraction method was the most beneficial to the operation, and could be achieved using a cement grout (Minova’s FB200 grout) to stabilise the LRF in conjunction with implementing a sequence where the primary stopes would be backfilled with cemented aggregate fill (CAF). Footwall drives were developed adjacent to the rockfilled stopes, allowing for the installation of horizontal grouting conduits, as well as providing access to the top of the planned 3860 and 3900 level stopes for the placement of CAF. An interval at the base of the previously rockfilled stopes was grouted at multiple horizons to achieve the required thickness, with a comprehensive quality assurance/quality control (QA/QC) process undertaken. Primary stopes were CAF backfilled via an arrangement of downhole winzes, linking the top of primary stopes to cross-cuts developed off the associated footwall drives. CAF was delivered underground through an open reticulation network that was extended to the specific levels. Overall the successful implementation of the revised mining method effectively increased ore recovery while maintaining control of overbreak and dilution, providing significant financial upside. This was achieved while maintaining effective controls in light of the changes to the risk profile. Stabilisation of the existing rockfill has allowed the extraction of stopes to full height, including the originally designed sill pillars, representing an average 23% increase in ore tonnes on the initial design, with dilution from the stope crowns averaging less than 1%. The use of CAF in association with primary/secondary stoping, eliminating the need for rib pillars, has yielded an average 47% increase in ore tonnes compared to the base case mine design.

Mar 15, 2021

By D. A. Hayman, J. D. Steenkamp, G. M. Denton

Design of furnace containment systems can be based on one of two design philosophies: Insulating or conductive lining designs. In insulating lining designs, management of the compatibility between refractory materials and process materials (typically liquid metal and/or slag) is an important criterion for furnace design, and an important process parameter to control during furnace operation. In conductive lining designs, management of the integrity of the layer of frozen material (freeze lining) on the interface between the liquid process material, and the refractory lining, is important. For example in ferrochromium production, both lining design philosophies are applied. The work presented here discusses the significance of lining design philosophy in the context of ferrochromium production.

Mar 1, 2017

By Thomas Fraser

"El objetivo del presente texto es describir las características del lavado del carbón bruto producido actualmente en La Galgada, Ancash. Para ello, se revisa el registro y la comparación comparación de datos de prueba realizados entre 1945-1955. Desafortunadamente no se tuvo información de los lugares de trabajo para la selección de muestras, por lo cual no se las considera representativas de la producción obtenida en una operación a gran escala. Empero, los datos de las muestras en conjunto permiten una mayor índice de representación, y muestran la fluctuación en consumo que una nueva planta tendría que ser capazde manejar. Asimismo, se sugiere que dentro del diseño de plantas definitivas, el diagrama de tratamiento, indica un plan que pudiera ser adoptado ventajosamente, si surge el caso de que el carbón de Ancos y La Galgada sea empleado principalmente para la producción de combustible para altos hornos. En este caso, se supone que la planta lavadora estaría situada en Chimbote, como parte integrante del horno de coke y planta de sub-producción, y que el lavado daría un producto uniforme de no más de 10% de contenido de cenizas. Esto es solo una solución posible, que ofrece grandes posibilidades en la actualidad, en vista de los planes corrientes para una expansión eventual de la industria del acero, basada en el funcionamiento convencional de altos hornos que utilizan un combustible fabricado a base de antracita."

Jul 20, 1956

By J. M. Adams

It is my purpose to give some of the results obtained by an experience of nearly seven years in working ores by the method frequently called the Washoe Process, and in several mills of which I have had charge, but principally in the Owyhee Mill, at Silver City, Idaho, which had twenty 650-pound stamps, and sixteen pans. I shall discuss here merely the mechanical details for working ores generally, subdividing the subject as follows : 1. Preparation of the ore for the stamps; 2. The crushing in the battery; 3. The settling of sand or pulp in vats or tanks; 4. The treatment in the pans; 5. The results obtained in settlers, agitators, and concentrators; 6. The straining of quicksilver, cleaning of amalgam, and retorting; 7. The saving of slimes and their subsequent treatment; 8. The loss of quicksilver. For descriptions of the various kinds of orebreakers, stamps, tanks, pans, settlers, etc., I must refer to the various works on these subjects, prominent among which are the reports of the United States Commissioner of Mining Statistics,and the volume on "Mining Industry," the third volume of the United States Geological Survey on the Line of the Fortieth Parallel through the gold and silver bearing regions of the great West, undertaken under the able guidance of Clarence King, assisted by Mr. James D. Hague and others. In this discussion it will be assumed that the general arrangement of the quartz mill is understood; and the question will be treated how to secure, from such a mill, the greatest economy in working, combined with the largest results. This place seems fittest for a single preliminary suggestion—namely, that there should be double "floors" throughout the mill, so that nothing can sift through and be lost.