Search Documents

By Dean Lindsay, Inna Dymov, Mariam Melashvili, Jim Smolik, Chris Fleming

"This paper presents results from the proposed cyanide detoxification circuit for Seabridge Gold’s KSM project. The proposed flowsheet uses a two-stage CCD (counter-current washing/decantation) circuit to transfer the flotation products CIL(carbon-in-leach) barren solution to a SART process (Sulphidization, Acidification, Recycling of precipitate, and Thickening of precipitate) to recover copper and free cyanide from the copper cyanide complex. The SART barren solution is then treated by an AVR process (Acidification, Volatilization of HCN gas, and Reneutralization) to concentrate the cyanide that was liberated in SART for recycling to leach. The washed CIL barren pulp (the CCD underflow) is treated with the SO2 /Air process to oxidize residual cyanide.The goal of this complex flowsheet is to recover and recycle as much cyanide as possible and produce a final effluent containing less than 0.5 mg/L copper and CNWAD at the lowest cost. The SO2/air process is capable of achieving low residual CNWAD (<1 mg/L) in the final product, but the persistence of aqueous copper above the target level has been detected in the treated solution in some instances. The expected high concentrations of copper and cyanide in the KSM CIL barren ( >200 mg/L each species) and the difficulties this might create for the SO2 /air process was a key factor in the decision to consider including the washing, SART and AVR steps in the project flowsheet.The target concentrations of CNWAD and Cu were readily achieved after aging the SO2 /air treated pulp, as would occur in a tailing or polishing pond. This suggests no additional treatment will be required to sustain low levels of these species in the final plant effluent."

Jan 1, 2015

By Gerald T. Homce

A system capable of monitoring mine electrical power systems and detecting impending component failure could significantly improve power system safety and reduce unscheduled equipment downtime. Such monitoring would require a method of evaluating electrical parameters, calculated from terminal values, for indications of component deterioration. The U.S. Bureau of Mines has targeted electrical failure of squirrel cage induction motors and examined the use of mathematical models to aid in this evaluation. The initial stage of this work is complete, and has produced polynomial networks called adaptive learning networks (ALN&apos;s) that can detect and quantify winding insulation leakage simulated on laboratory motors. In this modeling process, empirical data from laboratory motors were used to select the electrical parameters most significant for assessing motor conditions, and mathematical expressions relating these parameters to simulated deterioration were formed. ALN&apos;s developed thus far can process readily measured motor terminal information and quantify power and current levels of laboratory-simulated leakage to within 1% and 3% of full load values, respectively, for motors in the 10- to 150-hp size range. The next stage of this research is validation of these ALN&apos;s for actual motor failures; this stage is currently underway, using accelerated life testing of laboratory motors.

Jan 1, 1993

By Michael M. Hamilton

In 1984 and 1985 the U.S. Bureau of Mines performed a mineral survey of the South Jackson Mountains Wilderness Study Area covering 60,211 acres of mountainous terrain of Humboldt County in northwestern Nevada. Approximately 550 lode claims have been located within or adjacent to the study area from 1900 to the present. Total recorded production for the area is 28.19 ounces gold, 1,105 ounces silver, 959 pounds copper, 6,016 pounds lead, and 12,446 pounds zinc; an additional two carloads from one mine contained an unknown amount of metal. In early 1986, there were eight active properties with a total of 126 claims. Wescord Resources and Long Lac Exploration (Texas) Inc. are involved in a joint exploration of the Jackson Mountains for volcanogenic massive sulfide deposits. Development at the Claudia mine continues in 1986. Results of the survey indicate that there are no identified mineral resources or reserves within or adjacent to the study area. Twenty-two properties have mineral occurrences containing gold, silver, copper, lead, zinc, iron, antimony, vanadium, and cobalt, with silver, copper, and iron being the most abundant.

Jan 1, 1987

Abrasivity and wear resistance are not intrinsic properties of materials, but rather parameters describing the interaction between the wear part and the material exerting the wearing action. Moreover, wear or, at least, that part of the wear which is due to the cumulative effect of minute scratches, is linked to the hardness disparity concept. Abrasivity, in this context, is a relative concept, pertaining to a metal-rock pair, rather than to a rock. Based on this assumption, a methodology has been developed and checked against actual cases, enabling description of the abrasiveness of arock or the abrasion resistance of a metal through the ratio of comparable quantitative indicators. The paper describes the methods and provides examples of applications to practical cases(namely: rock cutting, excavation by means of tunnel boring machines (TBMs), rock crushing, and hydro-mill cutting).

Jan 1, 2012

By Richard Manrique

"La implementación del proyecto de modernización de la fundición de cobre de Southern Peru Copper Corporation requiere cambiar la metodología de funcionamiento de los sopladores para la etapa de conversión. En este sentido, el presente texto señala los aspectos del Sistema de control maestro de reparto de carga implementado en la Fundición de Ilo con excelentes resultados, logrando mejorar el rendimiento de los equipos con una antigüedad de mas de 30 años e invirtiendo tan solo en nuevos controladores en una etapa ligada directamente a la línea de producción. Mantener la variable primaria presión en la red de sopladores, compartiendoóptimamente la carga entre los sopladores en la red, mientras que, se minimiza el riesgo de surge, consumo de energía y los disturbios en el arranque y el paro de sopladores individuales, el sistema deberá ser lo suficientemente flexible que no deberá de perturbarse ante la salida frecuente de los convertidores, es decir deberá de mantener las presiones y flujos a la descarga del manifold ante las variaciones en el consumo de aire todo esto con un mínimo de venteos al ambiente."

Sep 19, 2006

By J. Torma-Krajewski, C. Hipes

Many mining companies apply ergonomic principles, but it is done either informally and/or reactively. Examples of an informal approach include replacing worn equipment, such as seats, with models that have ergonomic features, or modifying tasks to eliminate safety hazards that will also reduce risk factor exposures that may result in musculoskeletal disorders (MSDs). A reactive approach is followed when modifying a task/equipment after an MSD occurs. Neither one of these approaches involves a systematic method of proactively applying ergonomic principles to actually prevent injuries or illnesses. This paper will discuss how Vulcan Materials Company applied ergonomic principles and the interventions implemented to reduce risk factor exposures.

Jan 1, 2007

By W. A. Heitbrink, J. D. Ashley, R. E. Gresh, J. A. Organiscak, A. B. Cecala

Many different types of mobile equipment used in surface coal mining utilize enclosed cabs to protect equipment operators. The overburden removal process is extremely dusty and can cause excessive exposure to respirable dust, especially crystalline silica. After equipment is used for years, many components of the enclosure deteriorate and its effectiveness is greatly reduced. This report discusses a cooperative research study performed on an Ingersoll Rand DM45E surface drill, retrofitted with a new Sigma pressurization and filtration system. Respirable dust concentrations were substantially reduced from 0.64 mg/m3 during pre-testing to 0.05 mg/m3 during post-testing with the new system, representing a 92% reduction in dust levels in the drill cab. This new system appears to be a very well-built and sturdy device, well-suited for the mining industry.

Jan 1, 2002

By Clark F. Grain

These investigations were undertaken as part of the Bureau of Mines program for the development and evaluation of high temperature nonmetallic materials. This report consists of thermal expansion and phase inversion measurements by high-temperature X-ray diffractometry on the principal oxides of beryllium (BeO), calcium (CaO), titanium (TiO2 ), zirconium (ZrO2 ), hafnium (HfO2), and thorium (ThO2); all were high-purity commercially available oxides. Thermal expansion values were calculated from unit cell dimensions measured at selected temperatures. Expansion was determined parallel to each major crystallographic axis for the anisotropic oxides: BeO, TOi2, ZrC2, and HfO2. Combined random and systematic errors in the thermal expansion values are considered to be less than 3 percent of the total expansion at 500° C. and approximately 2 percent at 1,000° C. No hysteresis in the expansion curves was noted between heating and cooling cycles. The Bureau&apos;s values were compared with published expansion measurements obtained by X-ray diffraction, dilatometric, interferometric, and telemicroscopic techniques. For anisotropic oxides, average linear expansion values were calculated from the volume expansion.

Jan 1, 1962

By D. Harrington

The code of hoisting signals for use in mines hoisting from one level, as suggested in this publication, is submitted to induce consideration of this subject by representative groups of the coal-mining industry, such as the lithe Inspectors Institute of America, National Coal Association, American Mining Congress, and others, as well as to -furnish a code of signals for use in those mines operated in States that do not have regulatory hoisting codes in their mining laws, or regulations. The signal codes described in this publication apply only to mines hoisting from one level and to slope mines. Mines that hoist from more than one level are referred to Bureau of Mines Information Circular 7289 Suggested Hoisting-Signal Code For Metal Mine Shafts, which suggests signals for hoisting from various levels or stations.

Jan 1, 1944

By R. J. Gochin, G. D. Schena, R. Spencer

The impact of a mineral project in a developing country is evaluated in the broad context of its economy using input-output models. Minimum economic theory is used to develop simple numerical models. Sets of technical coefficients are exploited in the development of linear models of the productive element of an economy. The analysis allows assessment of the overall economic consequences of a mineral development in which issues broader in scope than financial objectives need to be incorporated in the evaluation. In part 1, the framework for the development of the input-output model is presented. The model is refined to incorporate country-specific behaviour. The increased flexibility of the enhanced semi-input-output model permits a more confident investigation of the economy-wide effects associated with a new project in the mineral sector of a developing country. The relevance of the models is illustrated using an example from Namibia

Sep 1, 1991

THIS paper is the outcome of experiments carried on and experience gained. at the Waihi-Paeroa Gold Extraction Company&apos;s tailings plant at Waihi, New Zealand. The plant was erected to treat accumulated tailings which had been discharged into the Chinemuri River by the Waihi batteries.The Chinemuri River is a common sludge channel for all mining debris, tailings, and ashes from the power plants, the last being the cause of occasional high residues, which gave so much trouble to the management. The tailings were dredged from the bed of the river into barges by means of a Pohle air lift, the power being supplied: by a 13 b.h.p. Tangye oil engine driving an air compressor and a centrifugal pump. The sands were elevated from the barges by bucket-belt elevators over screens, to eliminate large particles and rubbish, into storage hoppers, and from there fed direct into four C. Judd Ltd. tube mills.The method of treatment was fine grinding in a weak cyanide solution, agitation in B. and M. tanks, filtration with turn-over vacuum filters, and precipitation with zinc shavings. The comparatively high values of the residues in gold gave a great deal of trouble, &apos;and it was not until repeated experiments were carried out that the cause of the trouble was located. While the value of silver residues remained stationary, the gold values...

Jan 1, 1912

By Alla D. Mah

The heat of formation of scandium sesquioxide (Sc203) has not been measured previously, and existing values for gallium sesquioxide (Ga203) are subject to large uncertainties. As a consequence, thermodynamic calculations involving these oxides hare lacked scientific exactness. This paper reports newly determined values of the heats of formation of gallium and scandium sesquioxides at 298.15° K., by combustion calorimetry. The corresponding free energies of formation are derived from heat and entropy data.

Jan 1, 1962

By K. Honkivaara, S. Junnikkala, J. Aho, K. Föhr, P. Lampinen

"Bubble area flux has been claimed to be a major tool to dimension flotation equipment. The paper describes laboratory scale (batch and 301 continuous cell using plant feed) and small-scale (1 ,8m3) industrial experiments with coarse-grained massive sulphide ore.Samples were taken with different froth thickness and air addition rates while the bubble size was measured with an UTC capillary device. Problems of averaging the bubble size measurements and the bubble area flux measurements are also discussed.Material balances were calculated using the commercial program BILCO. The flotation rate constants were calculated for pulp and for froth assuming that we can extrapolate the flotation rate constant of the pulp phase from tests using very thin froth thicknesses.The results indicate that the bubble area flux is not alone an adequate dimensioning tool. With fine sizes there was a nearly linear relationship between the bubble area flux and rate constant for constant impeller revolutions. For coarse sizes the form of the relationship is non-linear and seems to go through a maximum value. Thus the final flotation outcome is not a simple function of bubble area flux but depends on the particle size distribution and other more traditional flotation cell dimensioning variables. The effect of the froth residence time in the total recovery of coarse particles is large, but will not be treated in this paper."

Jan 1, 2000

By D. deV. van der Spuy

A procedure for optimizing the secondary cooling zone of continuous casters is proposed and illustrated by a billet caster example. The procedure consists of quantifying deviations from the required conditions of the secondary cooling zone?as far as temperatures, metallurgical length and reheating are concerned?by means of a ?cost function?. The optimal spray settings are then found by minimizing the total ?cost?. The billet caster examples serve to emphasize the importance of specifying the required conditions in a consistent manner. Some envisaged practical limitations of this approach are discussed.

Jan 1, 1999

By C. A. Brown

"Steady-state simulation has been used for over 20 years to optimise the operation of crushing and grinding circuits. Throughout that period continuing comminution research has been the basis for improving the models.Site surveys, ore characterisation, model development and investigation of different operating scenarios by simulation has proved to be a cost-effective method for improving plant performance. In this sense, this paper presents findings from experience with these valuable optimisation techniques with reference to specific case studies."

Sep 12, 2005

By S. Hunt, D. de Vries

Kansanshi Copper Smelter began operation in March 2015. The smelter features a single Isasmelt furnace for smelting, one 6-in-line electric furnace for matte-settling and slag-cleaning duties, four Peirce- Smith converters and two rotary anode furnaces. A 1,450 t/day oxygen plant and a 4,085 t/day sulphuric acid plant are included in the smelter operations. This paper gives an overview of the operational performance to date with summary data for each smelter section. Challenges such as an unforeseen refractory failure in the Isasmelt furnace in 2016 are discussed. Design improvements around the electric furnace are mentioned. Plans for potential future improvements are put into context. A consistent focus on operations, maintenance and continuous improvement has seen the smelter easily achieve its nameplate capacity of 1.2 million tonnes per annum of copper concentrate throughput. The smelter now operates consistently at a concentrate throughput rate of 1.38 million tonnes per annum of copper concentrate. INTRODUCTION The smelter was commissioned in March 2015. Design and commissioning of the smelter have been discussed by de Vries, Hunt, Hanschar and Louie (2016). The smelter rapidly ramped up to achieve nameplate production (1.2 million tonnes per year concentrate) and in 2018 operated consistently at the rate of 1.38 million tonnes per year concentrate. This paper presents major operational data for each section of the plant and describes significant events and improvements during the first four years of operation. The smelter flowsheet is shown in Figure 1.

Jan 1, 2019

By D. G. Krige

Using chip sample data and spatial structure parameters from a large mined-out section of a South African gold mine the advantages to be gained from a regular underground borehole drilling programme have been investigated for short- and medium- to long-term planning based on block valuations. The results have been compared with the current position, which relies invariably on the extrapolation of limited peripheral sampling data from raises, gullies or stope faces. Some preliminary work has also been done regarding the implications of such underground drilling on costs used for the present pay limit calculations. The results of the study, though preliminary, show that the net advantage of advance regular underground drilling could be substantial and that a more intensive follow-up research is warranted.

Jan 1, 2003

By J. M. Lottering

Paper written on project work carried out in partial fulfilment of B Eng (Chem) degree Operational factors influencing the electrostatic separation of mineral sands were investigated in a laboratory separator. Measurements were collected online by means of an optical sensor using diffused reflectance spectroscopy to determine the mineralogical composition. The results have shown that the roll speed and potential were the dominant operating variables, collectively explaining more than 83% and 68% of the product grade and yield, respectively. In contrast, the feed rate, temperature and position of the plate did not affect separation. The effect of the ambient relative humidity, ranging from 10% to 45%, could not be assessed conclusively and at best appeared to have a weakly beneficial effect on the product grade. Keywords: process modelling, high tension roll separator, mineral sands

Jan 1, 2006

By B. M. Nyombolo

Mintek has been involved in the development of bioleach technology for many years, initially for refractory gold extraction, and more recently also for base metals extraction. Mintek, in collaboration with its Australian technology partner (BacTech), is the technology provider for the Beaconsfield refractory gold bioleach plant. At present Mintek, BacTech and Peñoles are constructing a demonstration bioleach plant for copper-zinc concentrate treatment. Bioleach liquors produced in all applications have to be neutralized. In the copper-zinc case, neutralization is required for bleeding iron from the circuit and for adjusting the pH value ahead of solvent extraction. In the refractory gold bioleach circuit, neutralization is required for producing a stable iron-arsenic residue. Some of the challenges encountered in each of these neutralization applications are discussed, and examples of results obtained are presented.

Jan 1, 2000

By Gary L. Stecklein

This final report delineates the findings of the test programs, simulations, and analyses performed to determine the requirements for the effective application of berms and guardrails as truck restraint systems for elevated mine roadways. Included arts criterion for effective vehicle restraint for guardrail applications and recommendations for berm applications based on scale model tests and computer simulations. Full scale haulage vehicle-berm interaction field tests were performed to correlate the results of these model tests and computer simulations. Recommendations for the construction of berms were made on the basis of tests of berm bearing strength, response of the vehicle to different berms, and predictions based on the obtained correlation

Jan 1, 1981