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By G. ALBORNOZ, S. Utili, A. AGOSTI, C. VALDERRAMA, R. PELL, N. Morales

The steepness of the slopes of an open pit mine has a substantial influence on the financial return of the mine. The paper proposes a novel design methodology where overall steeper pitwalls are employed without compromising the safety of the mine. In current design practice, pitwall profiles are often planar in cross-section within each rock layer; i.e., the profile inclination across each layer tends to be constant. Here instead, a new geotechnical software, OptimalSlope, is employed to determine optimal pitwall profiles of depth varying inclination. OptimalSlope seeks the solution of a mathematical optimization problem where the overall steepness of the pitwall, from crest to toe, is maximized for an assigned lithology, geotechnical properties, and factor of safety (FoS). Bench geometries (bench height, face inclination, minimum berm width) are imposed in the optimization as constraints which bind the maximum local inclination of the sought optimal profile together with any other constraints such as geological discontinuities that may influence slope failure. The obtained optimal profiles are always steeper than their planar counterparts (i.e., the planar profiles exhibiting the same FoS) up to 8° depending on rock type and severity of constraints on local inclinations. The design of a copper mine is first carried out employing planar pitwalls, secondly adopting the optimal pitwall profiles determined by OptimalSlope. The adoption of optimal slope profiles leads to a 34% higher net present value and reductions of carbon footprint and energy consumption of 0.17 Mt CO2 eq and 82.5 million MJ respectively due to a 15% reduction of rockwaste volume.

Feb 9, 2022

By Nathan T. Lowe

This report updates an accounting of mines and prospects in the Seafoam mining district, Custer County, Idaho, begun during mineral appraisal of the Idaho Primitive Area. Thirty-two mine and prospect locations have been added to the Bureau's Mineral Industry Location Subsystem (MILS) data base as a result of initial phases of mineral appraisal of the River of No Return Wilderness; most previously known locations were field checked and the updated information added to the data base. The district's major deposits include polymetallic fissure veins of gold-silver-lead-zinc-copper hosted by granodiorite and quartz monzonite which have been intruded by dikes ranging in composition from rhyolite to dacite, and vein type replacements of silver-lead-zinc-copper hosted by calcareous xenoliths imbedded in major intrusives. These deposits may be related to the intrusion of the Rapid River pluton or the Casto pluton. The dominant northwest structural trend is parallel to an aeromagnetic high, a weak gravity salient, and the Blue Bunch Mountain dike swarm.

Jan 1, 1983

By T. L. McCall

A short description of mining practice in the Sydney coal field in general is followed by a discussion of the operations in the No. 12 colliery of the Dominion Coal Company, Limited, as being typical of the trend in operating methods obtaining throughout the field. Development of longwall mining to the present system of three walls in line is outlined, together with a summary of the cycle of operations involved in systematic operation.

Jan 1, 1944

By B. B. Broms

A method for calculating the bending moment induced in misaligned or bent piles is described, The maximum bending moment varies with the angular rotation between the pile segments, the coefficient of horizontal subgrade reaction of the soil and the flexural rigidity of the piles. A case history involving damages to misaligned 365 x 365 mm square precast concrete piles is described.

Jan 1, 2010

By R. P. King

The MODSIM mineral processing plant simultor is used to find optimal combinations of target separation specific gravities in a typical modem coal washing plant. A plant that is set up with these optimal targets can deliver up to 10% more yield at the same ash content as the same plant set up with separation targets chosen by conventional methods. MODSIM is the only simulator currently available that can simulate the liberation of pyrite and other mineral matter during open- and closed-circuit grinding operations. The simulator can therefore be used to assess the benefits of grinding operations in the flowsheet.

Feb 24, 1997

By J. K. Whyatt, W. P. Blake, T. J. Williams

A study at the Idaho mine revealed that, despite the apparent randomness of seismic events, common characteristics defined five recurring types. These characteristics included the geological structure that slipped, the first-motion pattern and the location and intensity of damage. Many large events caused little or no damage, and where it did occur it was concentrated at intersections between slipping structures and mine openings. Of 39 events between 1989 and 1994 with local magnitudes of 2.5 or more, 10 were caused by slip on bedding planes in the southern limb of the mine, 6 occurred near the vein along a set of near-vertical faults that form the central shear zone, 8 were strike-slip events on the Southern Control Fault, 4 were by slip on the vein itself and 10 involved strike-slip and/or dip-slip movement along the North Control Fault. Strategies for control of mining-induced seismicity need to consider all five types of event, lest a strategy to reduce one type increases others

Jun 19, 1905

By A. H. WHITE, PERRY BARKER

In a consideration of the various means whereby more economical and more efficient use may be made of the fuels in the United States, the possibility of obtaining for the production of illuminating gas other and cheaper fuels than the Pennsylvania coals demands attention. For the Government, as well as for private corporations and the householder, there can be no more economical and efficient way of using some coals than through the medium of illuminating gas. In the stove, gas reduces the labor cost of heat production and lessens the drudgery of the kitchen; burned in the Welsbach mantle, it is an excellent and cheap illuminant. In addition, the coke that remains after the gas has been recovered furnishes a smokeless fuel that has about the same heating value as anthracite. Hence any investigations that will indicate how local coals through proper treatment may be substituted for the higher priced and rapidly vanishing Pennsylvania gas coals will bring about lower prices for both gas and coke and will also aid to conserve for use in metallurgical processes the coking coals of Pennsylvania and of ot,her States. The annual drain on the gas-coal resources of this country and the importance of the gas and coke industries are indicated by the fact that 8,390,129 tons of coal were carbonized in retorts in the United States in 1909. The resulting salable products from by-product ovens were 15,791,220,000 cubic feet of coal gas, 6,254,644 tons of coke, and 60,126,000 gallons of tar. The total value of all by-products was about $28,508,637.

Jan 1, 1911

By B Roache, J O’Brien, M Gray

Admixture use in cement products is commonplace in the construction and mining industries. Many Australian mines have an operational concrete batch plant and stock hydration control and water reducing admixtures. The benefits of admixture use, especially in shotcrete is understood and well documented. Cemented rock fill (CRF) is used to fill stope voids and create stable vertical and undercut surfaces at some Australian mines. These mines generally mix rock fill with a slurry of cement and water without the use of admixtures. Recently published work on optimisation of CRF mixes has mainly focused on the strength increases associated with changes to the mix grading proportions by the addition of fines, but not focusing on the potential benefits of admixture use. Admixture use in CRF may be the simplest CRF optimisation method, as the admixtures will often be added by the push of a button at the batch plant. A CRF testing program was undertaken to test the benefits of admixture use in terms of strength gain, using hydration control additives (HCA) and high range water reducer (HRWR) admixtures. Rock fill gradings were strictly controlled in the test process to allow clear definition of the difference admixtures provide in compression at 28 days. The testing results define admixture associated strength gains in a 6 per cent general purpose (GP) cement by dry weight CRF mix (131 kg of cement/m3). Costings have been developed to allow a mine operator to understand the cost benefits of admixture use in CRF due to reduced operating costs. Operational efficiency advances and a suggested admixture implementation plan for CRF optimisation is offered.

Nov 29, 2022

By F. Parada Torres

Xstrata Tintaya S.A. opera el yacimiento a tajo abierto y procesa el mineral en dos plantas: Planta Concentradora de Sulfuros y Planta de Lixiviación de Óxidos, donde anteriormente consideraba al mineral mixto complejo como intratable en la planta concentradora, por lo que se le destinó a ser tratado como óxido marginal en la planta de lixiviación. En este sentido, el presente texto describe el nuevo tratamiento al mineral complejo en la planta concentradora. De forma que se busca definir las variables geometalúrgicas del mineral de Chabuca Norte, optimizar los procesos metalúrgicos del mineral mixto mediante la investigación geometalúrgica, así como correlacionar el entendimiento de la geología y alteraciones del yacimiento con los procesos metalúrgicos y crear valor mediante la optimización de la tasa de tonelaje de tratamiento y el incremento del porcentaje de recuperación de cobre en el proceso.

Sep 12, 2011

By Robert N. Roby

This report is one of a series based upon investigations made and being made within the Missouri River Basin in Montana by engineers of the Bureau of Mines , Albany Branch , Mining Division . These investigations are made primarily to provide preliminary information to Department of Interior agencies and others concerned with the planning of the proposed Federal power developments within the Missouri River Basin . The present report has been designed to permit public distribution of the factual data obtained . The field investigations in Meagher County were made during tually all 1948 ; Vir- known metallic mineral occurrences within the county were investigated ; some nonmetallic mineral deposits also were investigated . The investigations cannot be considered complete , however , because some long-inactive mines or prospects may have been missed . Most of the old mine and prospect openings are caved; many are completely inaccessible . Many of the claims located years ago have been abandoned ; others have been relocated under different names and ownerships . Because of such conditions , much of the information regarding their development and operation necessarily has been obtained from Federal and State publications , supplemented by information provided by owners and local residents .

Jan 1, 1950

By C. F. Strydom

Paper written on project work carried out in partial fulfilment of B. Eng (Mining Engineering) degree The Self-directed work team concept is the product of relentless performance pressure on American industries during the late eighties and early nineties from other world industrial leaders like Japan. The concept proved to be a successful vehicle by which the Americans could increase their production and improve their safety statistics. The aim of this study is to evaluate the concept as a means to improve the overall performance on South African goldmines. he study is directed by a historical research section, answering questions like: ?Why do we need to change? ?What is a Self-directed work team? ?What are the principle advantages of the concept? ?What are the essential requirements for the concept to succeed? The study also includes an empirical research section that focuses on the current Self-directed work team situation in the South African gold mining industry. The empirical research section is limited to three case studies within Anglogold due to a study period of only six weeks. The mines chosen for the case studies have been labelled Mine 1, Mine 2 and Mine 3. The latter being the base mine allowing for a more in depth study. This includes a perception analysis towards Self-directed work teams within the mine. The study proves the truth of the Latin proverb ?Tempora mutantur, nos et mutamur in illis? meaning ?The times are changing, and we are changing with them?. The chief change catalysts identified are a dwindling gold price and a projected labour crisis. From the study it is evident that the Self-directed work team concept disposes of the critical parameters required for a dramatic improvement in performance. The study also indicates that for the concept to succeed, certain factors like top-level commitment and management-employee trust have to be in place. Sadly, the concluding part of the study proves that very few of the identified critical success parameters are present in the South African gold mining industry. This can serve to explain why the industry only has success with the concept when monetary gain is the chief motivator. The study only focuses on the reasons why the concept is not performing to its full potential and does not wander into explaining the reasons for the current unsupportive milieu in the industry. Self-directed work teams could well rescue the South Africangold mining industry but currently we are driving a square pin into a round hole! [Terminology SDWT?Self-directed work teams AEL?Adventure Experiential Learning ISW?In-stope worker POLC?Plan, organize, lead and control TEC?Total employee costed Silo?The confinement of departments preventing networking JCI?Johannesburg Consolidated Investment Co. Ltd]

Jan 1, 2002

By L. Vollert

In August 2018, the first full-scale HydroFloatTM cells for the recovery of coarse composited copper and gold were commissioned at Newcrest’s Cadia Valley operation in New South Wales, Australia. The primary objective of the installation is to recover coarse value-bearing composites that are lost to conventional flotation tailings, without the need for additional power input for particle size reduction to improve mineral liberation. This paper examines the application of Eriez HydroFloatTM technology for the recovery of coarse, poorly liberated copper sulphide particles drawing on recent experience from lab scale testwork through circuit design and commissioning of the full-scale installation at Cadia Valley. INTRODUCTION In the face of declining copper head grades and a tightening regulatory environment around the use of wet tailings dams, the processing of copper ores at coarser particle sizes has become a focal point for the industry. Sulphide flotation using the Eriez HydroFloatTM is one of the emergent technologies that sits under this umbrella of coarse pre-concentration. It has been demonstrated through numerous lab and pilot scale testwork programs carried out by Newcrest and others (Awatey, Kohmuench, Thanasekaran, Skinner & Zanin, 2013), to improve the flotation recovery of sulphide-rock composite particles with low surface liberation, relative to conventional flotation technology. The HydroFloatTM technology has been used widely for the recovery of coarse potash, phosphate, coal, vermiculite, spodumene and diamonds but has never been applied at full scale in either gold or sulphide flotation. In August 2018, the first full-scale 3.4 m diameter HydroFloatTM cells for the recovery of coarse composite copper and gold were commissioned at Newcrest’s Cadia Valley operation in New South Wales. The primary objective of the installation is to recover coarse value-bearing composite particles that are lost to conventional flotation tailings, without the need for additional upfront power input for particle size reduction to improve mineral liberation.

Jan 1, 2019

By Avery H. Reed

RECORD production of cement, clays, salt, sand and gravel, and stone highlighted the mineral industry of the State in 1956. Coal and iron-ore production declined owing to increased imports of foreign iron ore and decreased demand for metallurgical coke. Alabama ranked second in production of bauxite and of native asphalt, and third in output of iron ore. New developments in the State included the Citronelle oilfield and its 97 wells, which more than doubled the total production of petroleum compared with 1955. There is no question about the impetus that field has given to the oil and gas industry in Alabama, now 13 years old. The State's 4 oilfields are in southwest Alabama and its 1 gasfield is in Marion County, in the Warrior coal basin.

Jan 1, 1958

By D M. Frantois-Bongarton

Variograms can be powerful tools for the analysis and control of process streams and their sampling. Their uses and proper utilisation have been described somewhat unclearly to date, and their limitations and precautions of use are too rarely mentioned. The general meaning and properties of the variogram tool and its use in geostatistics are therefore reviewed in details to derive a critical view of its proper use for process control: what to expect from it and what it cannot deliver and which uses are illusory or potentially misleading. A summary of GyÆs seminal work accompanies this essay to put the concepts into historical perspective.CITATION:Frantois-Bongarton, D M, 2012. Review of variogram properties and remarks on its use in process control, in Proceedings Sampling 2012 , pp 175-180 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 21, 2012

By Herbert Cremer

The United States,-the largest nickel consumer in the world, produces virtually no nickel from domestic ores. Dependence upon outside nickel - sources and increasing strategic, importance of nickel focused the attention of the United States on deposits within its boundries. The most likely domestic sources of nickel are low-grade oxide and silicate deposits, such as the Cle Clum deposit, Kittitas County, Wash., and the Riddle deposit, Douglas County, Oreg. The Federal Bureau of Mines, Northwest Electrodevelopment Laboratory, Albany, Oreg. has been investigating electric smelting of low-grade oxide and silicate nickel ores. These smelting studies have been on selective reduction to produce low-carbon ferronickel. Selective reduction is based upon the relative reducibility of: nickel, iron, and chromium, in the order named, when the charge contains insufficient carbon or other reductants to reduce the entire quantity of these metals present in the ore.

Jan 1, 1954

By Todd Schrauf, James Scott, Mark Smith

"Cyanide heap leaching of gold ores in areas with extremely low winter temperatures requires special considerations to prevent freezing of the leach solution. Factors that impact the solution temperature include ore temperature at the time of stacking and during operation, burial of drip irrigation lines, use of geomembrane covers and heating of the leach solution. Thermodynamic modeling was performed to simulate expected ore and solution temperatures under different operating strategies for Kaminak Gold’s Coffee gold project in the Yukon Territory. Mean monthly temperatures at the site ranged from a low of -22.5 °C (-8.5 °F) to a high of 13.6 °C (56.4 °F), while in situ ore temperatures ranged from -0.5° to about -1.5 °C (31 ° to 29 °F). The modeling results were used to optimize the operational parameters and indicated that a combination of drip line burial and heating of the leach solution during the winter months was required to maintain solution temperatures above freezing during the initial years of stacking, although as the size of the heap increased, heating was no longer necessary.Modeling objectivesThe successful operation of a cyanide heap leach under extremely cold winter temperatures requires the implementation of operational strategies to prevent freezing of the leach solution and the ore within the heap. Thermodynamic modeling of the heap provides the means to quantify the effectiveness of these different operational parameters on maintaining the required operating temperatures to avoid freezing within the heap. The operational parameters that were evaluated with the model included:"

Apr 1, 2016

By R. J. Gajan

As part of its research program on secondary metal refining, the Federal Bureau of Mines has developed a fast method for determining aluminum, iron, copper, cadmium, and lead in zinc-base alloys. The new method is intended for use by trained technicians in laboratories with inexpensive equipment. It can be used either in the analytical laboratories of the many small plants that are characteristic of the secondary metals industry or in laboratories engaged in basic research to improve refining processes. A complete analysis for the foregoing elements can be made in less than 3 hours from a single sample in solution. The method is especially helpful when a small amount of sample is available. Aluminum and iron are determined spectrophotometrically and the other elements polarographically. The new method is now being used for control analysis in metallurgical research, and the results compare favorably with previously used spectrographic methods. Luke and Braun4/ described a photometric method for the determination of aluminum in zinc diecasting alloys in which the aluminum was complexed with Aluminon reagent (ammonium salt of aurintricarboxylic acid), forming a red lake. An adaptation of this method was used for determining aluminum. Beers law is obeyed between 0.01 and 0.06 milligram of aluminum.

Jan 1, 1961

By Ian McC. Stewart

"Seam gas flow in coal mines takes place through a medium which has both capacity and resistance and can therefore be expressed in terms of the basic diffusion equation, provided that the characteristics of the system can be adequately described. It may be possible to lump the variations from point to point in a seam together as an effective diffusivity. The paper discusses the characteristic flow-time patterns for various types of openings and the particular features of coal and seam which influence the diffusivity.Two field experiments are described in which gas make to a heading and to a borehole were measured in a mine for which considerable data on coal sorption properties were available. Incremental gas flow measured from the borehole experiment predicted the actual flow from the heading measurements remarkably well. The effective permeability adjacent to the face was much higher than expected from the properties of the coal. The incremental flow measurements to a horizontal (in-seam) borehole showed a striking picture of advancing 'relaxation' behind the face which is not discernible by other experimental means."

Jan 1, 1971

C.A. MITKE, *Bisbee, Ariz. (written-discussion-? ).--The advantages of the incline-slicing system have' been ably pointed out by Mr. Scott in his paper in the November, 1917, Bulletin, and also by Mr. P. B. Scotland in the Engineering & Mining Journal, Apr. 7, 1917. From the standpoint of efficiency and economy this method is far superior to the top-slice system as generally practised. However, as regards ventilation, and the danger of mine fires, it is just as necessary to use a mechanical ventilating system in mines worked by this method as it is in those worked by the horizontal top-slice system. Mechanical ventilation not only improves working conditions in top-slice stopes but, if properly designed for the particular mine in question, permits an immediate attack to he made in the event of a mine fire with a greater degree of safety to the men. In the course of time, incline top-slicing will probably take the place of the horizontal top-slicing system just as the incline cut-and-fill has superseded the horizontal cut-and-fill stoping method. While incline top-slicing has been tried in several districts on a very limited scale with inconclusive results, the Coronado is the-only large mine at which it has yet been thoroughly tested, and there it proved to be a complete success. As Mr. Scott's figures show, the tonnage has been more than doubled, with a simultaneous reduction in costs. As has been the history with all other innovations in mining, considerable hesitation will probably be shown in introducing this method in other mines. For example, when the incline cut-and-fill system was put forward as a substitute for the horizontal cut-and-fill stoping method many mining men of good repute were doubtful of its success and post-poned its introduction as long as possible, giving as their reason certain geologic conditions which would make the incline cut-and-fill impracticable. At the present time, most of the mining companies in the South-west, who in the past had used the horizontal cut-and-fill system, have already changed over, or are in the process of changing, and have proved that in the majority of cases horizontal cut-and-fill stopes can be successfully operated under the incline cut-and-fill system. Large horizontal cut-and-fill stopes can now be found in only a few exceptional cases, and

Jan 3, 1918

By Lassi Klemettinen

For better understanding and maximal value utilization of the WEEE smelting process, the behavior and distribution of different trace elements must be known. In this study, the behavior of nickel as a trace element was studied in an equilibrium system with metallic copper—spinel saturated iron silicate slag (with 3 wt-% K2O)—iron aluminous spinel—gas. The experiments were conducted in alumina crucibles at 1300 °C, in oxygen pressure range of 10−10–10−5 atm. A time series of 15–60 min experiments was also conducted for investigating the formation rate of the primary spinel phase in the system. The results show that the distribution coefficient of nickel between metallic copper and liquid slag changes from approximately 70 to 0.4 along the increasing oxygen pressure range. In addition, a significant part of the nickel deports into the spinel phase. The spinel formation was investigated based on composition analysis results and visual observations from SEM-images.