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By Carl Hansen

Sonora Mining Corporation (SMC) operates the 6,000 tonne per day Jamestown open pit gold mine in the Mother Lode district of California. The mine has been in operation since January, 1987, and has produced approximately 7,800 kilograms of gold since start-up. The property consists of five ore bodies lying along a five kilometer stretch of the famous Mother Lode vein system. At present, only the Harvard ore body is being mined. The Harvard pit is centered around a historic underground mine of the same name that was operated from 1896 to 1916. The present ore body averages 2.5 grams gold per tonne as free milling gold and auriferous pyrite. The project consists of the open pit mine and concentrator complex in Tuolumne County, California, and a carbon-in-pulp leach plant located near Yerington, Nevada.

Jan 1, 1990

By C. H. van Eendenburg

"Installation of a 3.6 km long raw coal conveyor in the Balmer open pit was undertaken to improve over-all haulage efficiency. This paper covers the rationale behind this project, system design and construction aspects and initial operating experiences. The majority of the construction work was performed by our own personnel. Where feasible, used equipment was installed to reduce capital cost and facilitate a tight construction schedule.BackgroundWestar Mining Ltd's Balmer Mine is located in the British Columbia Rockies, just outside of the town of Sparwood in the southeastern corner of British Columbia. The open pit mine, which has been in operation since 1969, currently produces about 6 million clean tonnes of coal per year, mostly for the metallurgical coal export market. Run-of-mine coal tonnages total between 9 and 9.5 million annually and waste removal volumes exceed 30 million bank cubic metres.The mine is a truck/shovel operation; loading equipment includes nine electric shovels, five front-end loaders and a hydraulic backhoe. The truck fleet consists of 40 units of 154-tonne, 181-tonne and 315-tonne capacity. The newer 154-tonne trucks are used for coal haulage for which they have been equipped , with tailgates to maximize their coal carrying capacity."

Jan 1, 1990

By Zhang Hongzhen

The fast convergence of boundary is a major problem of probability integral method, especially for the prediction of mining under thick alluvium, abandoned mine goaf, etc. To solve this problem and improve the accuracy of probability integral method, a modified model is constructed for surface movement and deformation based on theoretical analysis. In which, three weighted values i.e. 1, -1/t1, 1/t2 are set for the mining movement and deformation of three different major influence radius i.e. r1, R1, R2, respectively, then the parameters are selected as following: (1) Parameters are inversed based on the observation data, in which the subsidence factor q, deviation of inflection point s, displacement factor b are considered as generic parameters, the tangent of major influence angle tanß is modified as tanß2, that is the major influence radius r is modified as r2. (2) Inversion parameters of tangent of major influenceangle tanß or major influence radius r, based on the observation station edge data which beyond major influenc eradius distance from work-face mining boundary. The inversed tanß and r will be used as tangent of major influence angle tanß1 and major influence radius r1, respectively. (3) Other relevant parameters i.e. t1, t2, R1, R2, are calculated with the algorithm of this paper. A comparison experiment between the traditional and modified models has been conducted using the observation data from a observation station, the results show that in its central area, 58.6 percent of observation points accuracy is improved and 36.6 percent is decreased, while in its edge area, 61.5 percent is improved and 15.4 percent is decreased, totally, 68.6 percent is improved and 30 percent is decreased. Therefore, we can draw the conclusion that our modified model can improve the prediction predication accuracy, in particular, the boundary region.

Jan 1, 2014

By Sara Hornby

After almost half a century of experience in using DRI/HBI in electric arc furnaces (EAFs), and taking into account the decrease of natural gas cost in the USA, it is interesting to revisit some trends and controversial issues around this alternative iron source. This paper reviews aspects like the evolution of iron ore quality and its influence on EAF operation; DRI stockpiling and transport, regarding the risk for selfcombustion; optimum charge design; cold DRI/HBI charging (fifth hole, bucket, transporter); hot charging (ways and results); carbon content, metallization and silica in DRI/HBI, and its influence on EAF operation and performance; oxygen / carbon balance; chemical energy and DRI/HBI charge.

Aug 16, 2017

By L. L. Chasko, D. W. Alexander

Los investigadores del National Institute for Occupational Safety and Health’s Office of Mine Safety and Health Research han evaluado los efectos que la malla de control de suelos podría tener en la distribución de polvo flotante de roca y carbón en minas de carbón. El creciente uso de mallas para controlar el desconchado o caída de material del techo y las vigas introduce superficies elevadas adicionales para recolectar el polvo de roca o de carbón. Es posible que el potencial para la propagación de explosión del polvo se incremente si el polvo flotante de carbón no es convertido en inerte de manera adecuada. Adicionalmente, la malla podría interferir con la recolección de muestras representativas de polvo cuando se usa el método de recipiente y brocha desarrollado por la U.S. Bureau of Mines y usada por la Mine Safety and Health Administration para muestreo de banda. Este estudia hace una estimación del polvo de roca o carbón adicional que pudiera acumularse en la malla y desarrolla un método para recolectar muestras de polvo representativas atrapado en las mallas.

Jan 1, 2014

By C. T. Morley

The steadily increasing interest in high pressure grinding rolls (HPGR) as a legitimate alternative comminution technology for hard rock applications has led to a proportional increase in the demand for trade-off studies comparing HPGR with more established approaches, typically SAG-based but including AG and stage-crushing designs. The primary trade-off is between a) the higher capital cost typically incurred with HPGR-based designs and b) the higher operating costs of the more traditional technologies. However, if, through circuit design innovation, the capital cost penalty of HPGR circuits could be eliminated or reversed, then the need for trade-off studies would diminish.

Jan 1, 2012

By O. A. Bascur

Ores are becoming extremely variable with mineralogy and hardness disturbing the grinding and flotation circuits. The current grinding and flotation sensors provide large amounts of data for process optimisation. Adding the right context and operational events augments operational knowledge for proactive actions to improve the performance of the grinding and flotation circuits. A data-driven strategy is needed to enable operations, maintenance, and business personnel to quickly and easily take corrective action when abnormal conditions occur. A digital plant template transforms data into operational insights in real-time. It uncovers the hidden, idle and downtime losses. By measuring and managing these unproductive times, people find new ways of avoiding them, improving the profitability of the plant. The information created by the real time analytics enables the calculation of recovery in real time and develops predictive analytics models to find the best operating condition based on the type of ore currently mined. The creation of new workflows and collaboration between mining and concentrator plant and the enterprise, including services providers, are enabled. A grade recovery model is used to identify the best operating conditions in real-time. An optimal Gaudin size distribution shape is used to find the grinding operating conditions that optimise the metal recovery in the rougher sections of the mineral processing plant. Sensors in the flotation circuits enable estimation of metal recovery and determine the optimal froth depth and aeration profiles, using an industrial air holdup flotation model. The implementation of a recovery/grind strategy with industrial examples in non-ferrous metal concentrator is presented in the paper. Keywords: Digital transformation, soft sensors, predictive analytics, grinding flotation optimisation, flotation bubbles, particle size, particle size distribution shape, froth aeration profiles, flotation air hold up model, recovery predictive analytics

Jan 1, 2020

By G. C. Lipsyy

ALL mineral production? of Can11.da is transported in a mine car at some stage during its extraction. There are as many types and varieties of mine cars as there are of mines. Many of the cars in use were developed in the blacksmith shop. Others were designed by engineers and improved by the mine foremen and the mechanics. Every mine car has the ideas of miner, blacksmith, mechanic, and engineer incorporated in it. Many of these ideas are not generally known. This paper was written to make at least some of this information available to the mining industry. In drawings, tables, and notes, it gives all the important details pertaining to the cars. It .does not recommend any particular type of car for any particular piece of work, nor does it present drawings from which a car can be built. It gives the engineer or master mechanic information on many cars which he can apply to his own particular problems. It is hoped that this information will be of use to mine operators. If a few new ideas are conceived as a result of the paper, the author will feel that the effort of compiling it has been worth while. In order to obtain the data for the preparation of the paper, a questionnaire, copy of which is here reproduced, was sent to all the operating mining companies in Canada. An accompanying letter briefly explained the purpose of the paper and asked for co-operation in furnishing as complete information as possible.

Jan 1, 1945

By Chunyang Guan, Jilai Xue, Jun Zhu, Qiaochu Liu

"Al-Sc Alloys have showed many advanced properties for a wide range of industrial application, which is usually produced using thermal reduction process. This work is aimed to develop an electrochemical process to make Al-Sc alloy using industrial Hall aluminum reduction cells. The experiments have been carried out in a lab cell where NaF/AlF3-Al2O3-LiF as electrolyte, Sc2O3 as raw material, and liquid aluminum as cathode were used at operating temperature of 950 °C. The resulting Al contained 0.2 - 0.5 wt.% Sc that is the common range in its content for advanced applications. However, a small fraction of Sc was found from thermal reduction at Al melts interface. SEM-EDS and ICP-AES analysis showed a uniformed distribution of Sc at varying locations of the Al-Sc alloy sample. In addition, a higher Sc content in Al-Sc alloy can be obtained with introducing ultrasound through the cathode than that without it.IntroductionIn recent years, scandium has been investigated as an alloying element for aluminum alloys. With addition of a small amount of Sc, Al alloys can improve the strength, weld ability, resistance to re-crystallization and corrosion resistance [1-3]. Due to their advanced properties and potential applications, the demand for Al-Sc alloys will increase in the future. However, the difficulties in reduction technologies and the high costs in production process may limit their expansion in application areas.The current major method of producing Al-Sc alloys is to mix Sc into Al by melting Al-Sc master alloy. This alloying process has several technical problems, such as easy segregating and heavy burning loss, etc. The price of Sc metal or starting material is also high, so the mixing process is an expensive alloying method. Molten salt electrolysis is alternative method to prepare RE metal and RE alloys [4, 5]. It also can reduce the segregation of alloying elements. Sc2O3 is an ideal material as raw material with low price and decomposition voltage. Some work has proved that Al-Sc alloys can be obtained by electrolysis Sc2O3 directly in cryolite [6-8], or CaCl2 molten salt [9]."

Jan 1, 2012

By A Tolley

Bauxite residue or ‘red mud’ is a by-product of the Bayer Process, the primary process of alumina refining. Due to its high alkalinity and variable composition, its storage and disposal poses high environmental risks to water sources, surrounding ecosystems and human health. The high alkalinity (pH 12–13) is a significant factor in its classification as hazardous waste; to mitigate this, Australian refineries have integrated neutralisation processes into bauxite refining. Both sea water and carbon dioxide neutralisation processes are applicable. Multiple studies have demonstrated pH reduction from 12–13 to 7–10, depending on the method. The key advantages of CO2 neutralisation are that it allows for carbon sequestration and is more effective when utilised as a pre-treatment for recovery of metals, while sea water neutralisation is more established and has been integrated into two Australian refineries. This paper proposes the application of the bacteria Exiguobacterium oxidotolerans for bioleaching of iron from hematite in bauxite residue. The genus Exiguobacterium is characterised by its high levels of adaptability, halotolerance and alkaliphilic nature. E. oxidotolerans is successful at eluting Fe2+ from hematite via reductive dissolution, which complexes with oxalic acid produced during metabolism. This aquatic bacterium presents a novel process pathway for iron elution due to direct interaction of E. oxidotolerans with hematite via the cell membrane and operates within the pH range of neutralised red mud. The proposed mechanism is extracellular electron transfer, a microbial metabolic process where electron transfer is facilitated between bacterial cells and extracellular material. Currently this is being investigated for promotion of seaweed growth in coastal environments as soluble iron aids and fortifies colonies. This has potential downstream applications for cleaner iron and steel production. While theoretical, this paper explores the neutralisation, bioleaching and application of the Fe(II)- and Fe(III)-oxalate complexes formed.

Sep 18, 2023

By George S. Barnett

The Equis and El Roble projects are located in the Cordillera Occidental of Colombia. The Equis vein deposits have sulfide ore reserves of 95.9.5.5 mt (105.770 st) grading 8.51 g/mt (0.248 oz/st) gold and 12.4 g/ml (0.36 oz/st) silver with 0.94 % copper. 1.10 a lead and 11.06% zinc. Ore reserves at El Roble are estimated as 1.1% Mmt (1.21 million st) grading 4.89% copper and 3.39 g/mt (0.099 oz/st) ,old. Geologically possible reserves at Equis may total 1.6.Mmt (1.76 million it). El Roble has the potential to contain several tens of millions of metric tons. Exploration included diamond drilling, trenching, channel sampling, rock and soil geochemistry, geophysics and tunneling. Erratic high grade samples affect the weighting of channel and drill core samples. Secondary reconcentration of gold is also a factor. Sample maps and graphs show the distribution of values to be highly variable. Geostatistical treatment of some of these data gave important guidelines for parameters such as sampling densities, drill hole spacing and confidence limits.

Jan 1, 1984

By Roger G. Rowe

The Crandon deposit, located in northern Wisconsin, is a 65.8 million ton Precambrian volcanogenic massive sulfide deposit which averages 1.4% copper and 5.8% zinc. The deposit is classic in origin, mineralogy and shape. Comprehensive understanding of the geology of both the deposit and the project site has been fundamental to the credibility and success of Project feasibility studies and regulatory permit preparation. Mine development in the current investment and regulatory climate requires thorough and timely application of geologic tools. From 1977-1980 geologic activities were focused on the typical objectives of orebody delineation, reserve estimation, depositional geology, and general site investigation. Results from these programs formed the basis for the Project's preliminary feasibility studies. Since 1981 further geologic investigations have provided criteria for project design, site management, and operational permitting. Activities have included mine entry position definition drilling, developing geostatistical reserve modeling, large diameter (150 mm) core drilling for mill pilot samples, rock mecha¬nics testing, and evaluation of the glacial overburden/deposit geohydrology for computer simulation.

Jan 1, 1983

By R. V. Ramani

In this report, the application of the Open Pit Materials Handling Simulator (OPMHS) to a mine located in Ohio using a large stripping dragline, and truck and front-end loader (FEL) is described. The specific objective of the study is to demonstrate the application of the simulator to mine planning and coal production. On the basis of the simulations, it was concluded that the production from the haulback operation should be increased to accommodate improvements in both the stripping dragline's availability and mean cycle time. Several alternatives were studied for the best use of equipment if the present operating parameters could not be improved upon. No economic analysis of these proposals were made.

Jan 1, 1977

By D Laurence

Mining cycles have come and gone and with them there have been dramatic swings in the levels of interest and student entry into minerals-related education programs, hence graduate supply to the industry. So what is the problem? These trends will keep happening and the industry will keep on keeping on – or will it?This paper discusses recent trends in Australian minerals education programs and some international examples, together with some of the more recent initiatives taken by both the minerals education sector and the industry, such as the Minerals Tertiary Education Council (MTEC) and MEA. The real problem is that things will not just keep going the way they have over recent decades – there will come a time when there is no longer a supply of minerals academics available to provide the educational programs; and universities will simply shut down subcritical mass mining programs and invest in the much more lucrative programs such as commerce, law, medicine, etc. By the time this starts to happen it will be at least ten years too late for any last-minute reactive response by industry, if they were to try and avert such a consequence. International experience with mining programs bears out this scenario quite clearly.It is therefore timely for industry individual mines and mine management to take a much more strategic look at their role in the education sector. Sustainable mining also means sustainable minerals education – without one, the other will not function over the long-term. There is a pressing need for long-term strategic buy-in by industry into the education sector – not just for the good times, but also through the tough times. This means much more than a scholarship here or there, but includes such commitments as major industry-university research partnerships; collaborative recruitment initiatives and much more. The paper will discuss a range of such issues, problems and opportunities to address these important issues through strategic, comprehensive, long-term commitments by industry and equally significant and appropriate responses by the education sector. We care – do you?

Mar 21, 2011

By Dennis R. Dolinar

Physical property tests were conducted on drill core from three exploratory holes on the Naval Oil Shale Reserve near Anvil Points, Colo. Data and regression analysis curves are presented. Data obtained above the Mahogany zone were used to estimate the potential zone of surface effects from under-ground mining. Single specimen testing was primarily used to obtain Mohr's envelope and subsequent rock properties. The technique is shown to provide satisfactory results for this rock type with a significant reduction of core preparation and testing time.

Jan 1, 1981

By K. L. Gabby

Since mercury is chemically similar to silver, it tends to dissolve along with the silver and gold during cyanide leaching. Ultimately mercury is recovered along with the silver as mercury/silver/gold amalgam which requires retorting to remove the mercury prior to refining the silver and gold. A possible approach to separating mercury from silver and gold in cyanide leach solutions is to take advantage of the replacement reaction between [Hg(CN)4]2- and Ag2S, which results in precipitation of mercury as HgS while dissolving silver as [Ag(CN)2]-. Results are presented demonstrating that mercury can be removed from cyanide solutions with high effectiveness, while, at the same time, recovering additional silver in solution. Initial experiments with static flasks in the laboratory showed a high degree of mercury removal could be achieved. Results using actual metallurgical plant products in bottle roll tests indicate the process works on a larger scale, but also results in significant gold losses if the solution being treated has high gold levels, such as carbon stripping pregnant eluent solution.

Feb 23, 2014

By Claude P. Heiner

While the title of this paper embraces the entire West Coast, the author, in the interest of simplification. has confined the discussion to California-particularly the central section. California's population has, risen 45 pct since 1940. Its electric requirements have also increased, not only because of the growth in industry and population but also because of the widespread tendency of all types of electric consumers to use more electricity than ever before. The growth of California's electric utilities is shown by published data covering operations, of three of its large systems and is given in Table 1.

Jan 1, 1949

By Wei Victor Liu, Omer Faruk Ugurlu, Chengkai Fan, Bei Jiang

Accurate prediction of truck productivity plays a pivotal role in improving the efficiency and profitability of openpit mining operations. This paper proposes a deep neural network (DNN) model to overcome the challenge of predicting truck productivity in openpit mines. The prediction model was built using eight variables and was optimized by considering different train-test split ratios, numbers of hidden layers and neurons, and activation functions. The proposed model’s performance was evaluated using various metrics and compared with other commonly used machine learning algorithms. The results showed that the proposed model outperformed traditional machine learning models by achieving higher prediction accuracy. Moreover, a single-variable sensitivity analysis showed that haul distance is the most influential variable for predicting truck productivity. This study marks a pioneering effort in employing DNN to predict truck productivity in openpit mining, signifying a notable advancement in the field.

Jul 1, 2024

By W. J. Schlitt, K. McNaughton

A heap-leach field test was conducted during the 1993-1994 winter season at Carmacks, Yukon Territory, Canada. The purpose of the test was to demonstrate the viability of heap leaching Carmacks oxide copper ore in an arctic setting on a year-round basis. The test itself utilized a 5-m-diam crib loaded with 250 t of composite ore from the Carmacks copper deposit. The ore was stacked to a total height of 7 m in the crib, including 1 m of ore as an over- layer above the emitter system. This matched the plan for the commercial heap at the time when the test was started. The design also replicated an interior segment of the commercial heap. Leaching was done at a flow rate of 0.2 L/min/m2 using leachate at 21 °C. This temperature was maintained with no external heat input other than normal process heat transferred from electrowinning to the leachate via solvent extraction. Winter conditions were quite typical of those expected at the mine site. The temperature reached -54°C, while averaging -13°C over a three-month period. In spite of some flow system problems, leaching continued unabated, and freezing was limited to the insulating ore over-layer and isolated points near the outer crib walls. Thus, the test demonstrated that year-round heap leaching of Carmacks copper ore is practical in an arctic setting.

Jan 1, 2000

By Steve Karl

"The global underground construction and tunneling industry is in pretty good shape. Billions are being spent in shoring up aging infrastructure in the United States and other places, and new underground projects are being put out for bid.With each new project, comes new equipment, technology and tunneling methods. So it is incumbent on tunneling professionals to constantly improve their knowledge of the profession. This is where spending a few days with other underground construction professionals can assist the tunneler in keeping up.Every two years, tunnelers and underground construction engineers, contractors, suppliers, designers and owners from around the world gather for the Rapid Excavation Tunneling Congress (RETC). The 2017 conference was held in June in San Diego, CA. The UCA of SME puts on the conference.This years’ RETC attracted 1,400 attendees. The accompanying sold-out exhibit totaled 188 service and equipment suppliers. In addition, the conference had the UCA of SME bookstore, where the new History of Tunneling in the United States book was introduced. And a short course on tunnel rehabilitation was featured.Technical programmingRETC 2017 featured nearly 100 technical presentations. Topics covered the breadth of the global underground construction industry. Here is a sampling of a few. The proceedings from the conference is available from SME, 303-948-4200, www.smenet.org.Accomplishing extraordinary tasks as a machine supplier for Metro Doha: The construction of the Metro Doha in the State of Qatar established a modern, safe, efficient and integrated public transportation network. Upon final completion of multiple phases, the network will comprise four metro lines with a length of 216 km (83 miles) and 100 stations. Phase one comprises 112 km (43 miles of underground tunnels (56 km or 22 miles of twin-tube tunnels). Twenty-one earth pressure balance tunnel boring machines (TBM) were deployed by the four different joint ventures. The project was initiated, managed and supervised by the owner, Transport Authority Qatar Rail.Phase two of the Doha Metro will start upon the completion of Phase One in 2019 (Qatar Vision 2030). The owner placed full faith in the manufacturer’s abilities to deliver equipment of high quality, state of the art standards within the given time frame. This paper focused on the manufacturer’s scope of delivery and on the supplier’s high standards of quality in production, logistics and services."

Jan 9, 2017