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By H. G. Wickes

Virtually all fluorine consumed by the aluminum industry is as the electrolyte of the Hall-Heroult process for producing primary aluminum. A small amount of fluorspar is used but most fluorine is consumed as either aluminum fluoride or cryolite. Some fluorine- containing materials are used in secondary aluminum production, but the amount is negligible compared with primary production requirements. Any analysis of the future of the primary aluminum industry must take into account two powerful and closely related driving forces which are shaping that future. These factors are increasingly stringent restrictions on the emission of pollutants and the continuing cost-price squeeze. Nowhere do these factors combine more forcefully than in the area of fluorine consumption. We can safely assume that industry efforts to reduce fluorine consumption will be intensified and that these efforts will be fruitful. This paper will attempt to identify and quantify the factors and trends of fluorine consumption during the next decade. We will be concerned primarily with the demand for new fluorine. Sources of new fluorine will not be treated.

Jan 1, 1973

By Zhiyuan Ma, Yong Liu, Xianjin Lyu, Jianfang Lyu, Jikui Zhou

A stable and continuous leaching process for niobium and tantalum extraction from ferrocolumbium tantalum (FT) was developed. The effects of initial concentration of HF and H2SO4, grinding fineness, leaching time, and temperature on the leaching rate of Ta, Nb, Fe, and Si were studied. Experimental results show that the leaching rates of Ta, Nb, Fe, and Si were enhanced by the increase of acid concentrate, fineness, leaching time, and leaching temperature. The optimum process conditions are HF initial concentration of 5 mol/L, H2SO4 initial concentration of 2.5 mol/L, − 74 μm percentage of 65%, leaching time of 20 min, and leaching temperature of 25 °C. Continuous leaching of FT was carried out by feeding ore and acid every 20 min. By leaching with HF − H2SO4 for 4 h, then adding appropriate amount of HNO3 into the solution and keeping for another 1 h, a high Nb extraction rate of 99.8% was achieved. The established method provides a promising technique for the high-efficiency separation of niobium and tantalum from FT.

Jun 5, 2022

By D. A. Peterson

A research program is currently in progress at the University of British Columbia to determine the potential of composite cable bolt reinforcement in Canadian mines. Several prototypes of glass fibre cable bolts have been tested. Their evaluation consisted of lab testing at the University of British Columbia, United States Bureau of Mines (Spokane) and trial installations at Detour Lake, Winston Lake, and Myra Falls Mines. A market analysis of cable bolts within the Canadian mining industry has been completed. Fibre reinforced polymer composites have a high potential as cable bolt reinforcement in mining applications. They prove to be a viable alternative to steel cable bolting.

Jan 1, 1993

By E. K. Albert

Computer oriented simulation techniques can be effective in the design and analysis of complex mining systems. In fact, a number of computer software products are available for mine systems simulation. While providing a useful tool for the investigation of mine planning problems, the availability of graphic output was limited or non-existent. Computer graphics is a natural extension of mine simulation methods and provides a more dramatic level of understanding and interface with an engineer. With today's high cost of venture development, the need for an easy to use but complete systems model which includes the major elements of mine planning with an interactive graphics interface has never been more apparent. In this paper, the underlying philosophy of design of an interactive interface to a complete surface mining simulation model is described. The basic structures of the surface mining system and the simulation model are discussed. The methods and algorithms used to implement the various subsystems are presented. Practical considerations of the design of displays and user interaction are illustrated, especially as they apply to the application of the package by a mining engineer. A simple example is provided to demonstrate the concepts embodied in the model and to show how a simulation is built from mine data.

Jan 1, 1984

By Dominc C. Torre

INTRODUCTION Rapidly increasing capacities of equipment used to load and handle material at the face require improved haulage equipment and better methods of transporting the mined materials or "muck" to the shaft or slope and out of the mine to the processing plant on the surface. Increasingly, those transportation demands are being satisfied with underground belt conveyors. Such con¬veyors provide the most readily available, most efficient, and most reliable method of carrying materials in a continuous and rapid flow from the face loading equip¬ment to the surface plant. Almost universally, belt con¬veyors are used in coal mines and those nonmetallic and metallic mines operating in relatively flat bedded deposits. Belt conveyors are available in a wide range of capacities, mainly limited by belt width, belt speed, and weight of the material to be transported. They can be used on the level, on grades, on the surface, or under¬ground. They provide a rapid and constant flow of material, transporting the material as quickly as it is mined. Length of belt conveyors is almost unlimited. Where the haulage distance exceeds the practical capacity of a single conveyor unit, two or more conveyors can be used in series. Single conveyors more than 1.6 km (1.0 mile) long are common; multiple-unit conveyors in series operation are transporting materials over distances exceeding 16.1 km (10 miles). Depending upon mate¬rials being transported, job conditions, cost of the terrain being spanned, and alternative haulage methods avail¬able, conveyors can be conceivably economical for even greater distances. Table 1 lists maximum belt speeds recommended for most materials, relating belt speeds to belt widths. Table 2 lists capacities of typical conveyors of various widths and speeds, transporting commonly mined mate¬rials of various weights. ADVANTAGES OF CONVEYOR SYSTEMS For several years after their initial introduction, belt conveyors were available only with rigid side frames or a supporting structure of steel and concrete. That con¬struction limited underground applications, due to the cost and relative inconvenience of extending or retract¬ing the belt conveyor in the confined underground environment. However, during the last 20 years, wire-¬rope side-frame belt conveyors, as shown in Fig. 1, have become widely used in underground applications. Even wider use can be anticipated with their application to the fast movement of materials in surface mining operations. Advantages of the wire-rope side-frame belt con¬veyors were realized first in panel or section belt haulage in coal mines. Soon afterward, use of those conveyors was extended to gathering and main-line haulage. The mobility of the wire-rope side-frame conveyor is the principal reason for its success. The conveyor can be extended, retracted, dismantled, moved, and reassembled easily, even in relatively confined under¬ground spaces. The intermediate structure consists of rope support stands, wire-rope side frames, wire-rope tie-off stands, and the necessary carrying idlers and return idlers. An important and very attractive feature is the ability to suspend the conveyor from the roof in an underground mine, as shown in Fig. 2, leaving more room for improved housekeeping and allowing passage of face-service equipment, haulage vehicles, and other mining equipment. The conveyor's open construction allows quick and easy visual inspection of its com¬ponents for failures or malfunctions; it also facilitates checking and correcting conveyor-belt alignment. Other advantages contributing to the attractiveness and widespread application of wire-rope side-frame conveyors in main-line, slope, and surface installations include: lower capital costs, lower installation costs, lower maintenance costs, reduced impact on idlers and belting, reduced spillage and minimal cleanup, improved conformation to undulating terrain or mine bottoms, and the ability to span most obstacles without heavy structural support. CONVEYOR CLASSIFICATIONS Underground belt conveyors are classified normally according to their function. Generally, conveyors are classified into one of four main categories: 1) Panel or section conveyors normally receive the material to be transported directly from the face-haulage equipment. 2) Gathering conveyors are secondary haulage units that usually receive material from two or more panel conveyors. 3) Main-line conveyors transport all the material mined in the underground operations to the slope or shaft. Normally, they receive the material from two or more gathering conveyors. 4) Slope conveyors generally operate in tandem with the main-line conveyor, providing continuous Table 1. Maximum Belt Speeds Recommended for General Use Run-of-Mine Hard Ores and Belt Width, Coal and Earth, Primary Crushed mm (in.) m/s (fpm) Stone, m/s (fpm) 356(14) 1.52 (300) 1.52 (300) 406(16) 1.52 (300) 1.52 (300) 457(18) 2.03 (400) 1.78 (350) 508(20) 2.03 (400) 1.78 (350) 610(24) 2.54 (500) 2.29 (450) 660(26) 2.54 (500) 2.29 (450) 762(30) 3.05 (600) 2.79 (550) 914(36) 3.30 (650) 3.05 (600) 1067 (42) 3.56 (700) 3.05 (600) 1219 (48) 3.56 (700) 3.30 (650) 1372 (54) 3.56 (700) 3.30 (650) 1524 (60) 3.56 (700) 3.30 (650) 1676 (66) 4.06 (800) 3.81 (750) 1829 (72) 4.06 (800) 3.

Jan 1, 1982

By Siyu Song, Yanhong Wang, Guohua Gu, Linbo Huang

In this study, the effect of cations, Na+ and Mg2+, in saline water on copper flotation in the presence of calcium bentonite was investigated. It was found that as the concentration of NaCl was increased, the copper recovery initially decreased and then increased to above 99%, while the copper grade initially increased and then decreased. In contrast, as the concentration ofMgCl2 was increased, the copper recovery continuously increased, while the copper grade continuously decreased. The variation of copper recovery and grade was mainly attributed to the synergistic effect of pulp rheology and flotation solution chemistry. The underpinning mechanisms are the compressing electrical double layer and ion-exchange interaction between saline water and bentonite, which occur at the same time. Using salinewater slightly affected the pulp rheologywith a decrease in copper recovery at low NaCl concentration. Increasing the concentration of cations in saline water might even facilitate the flowing out of exchangeable cations, especially divalent cations, from the interlayer space of bentonite to the solution, resulting in the decrease of copper grade at high salt concentration.

Sep 10, 2020

By Paul M. Jr. Musgrove, Thomas D. Henderson, Mark B. Nesbitt

Introduction History. Vat leaching operations began in October 1953. Since that time, about 4.2 million tpy of oxide ore averaging 0.72% copper have been treated. Economic conditions, improved operating methods, and increased production facilities have allowed the ore grade to be reduced over the years. The average ore grade was 0.84% Cu during the 1950s, 0.68% in the 1960s, and was 0.50%, or below, during the 1970s. By 1961 some 35 million tons of oxide ore had been removed from the mine, exposing the underlying sulfide ore body. A 5,000¬ tpd concentrator was constructed and put into operation to treat the sulfide ore in November 1961.1 The original crushing plants were used for both oxide and sulfide ores, but by adding a third crushing shift, six days per week, the total ore treated was raised from 12,000¬17,000 tpd. Dwindling oxide ore reserves prompted expansion of the concen¬trator to 13,500 tpd in 19672 so that exhaustion of known reserves of both ores would occur at nearly the same time. Again, no additional crushing facilities were added during the expansion. It was anticipated that the treatment rate of oxide ore would be reduced from 12,000 to about 9,000 tpd. Instead, the addition of two crushing shifts per week and improved operating procedures have increased the treatment rate to 26,500 tpd-13,000 tpd to the leaching plant and 13,500 tpd of sulfide ore treated in the concentrator. Geology. The Yerington ore body is a disseminated porphyry copper deposit where a quartz monzonite porphyry intrusive contains the major part of the ore values, with some copper mineralization found in the adjacent granodiorite and other rocks. The geology of the Yerington Mine was aptly described by J. R. Wilson (Mining Congress Journal, June 1963). The ore body is one of few porphyries where geologic conditions were optimum for the formation of an important concentration of oxidized ore with minimum economic effect of secondary enrichment. The principal mineral in the oxidized zone is chrysocolla, which irreg¬ularly occurs dispersed throughout the rock and as narrow seams along fissures. The grade of the ore in the oxidized zone is generally the same as in the primary sulfide below, although some massive concentrations do occur as vein-like fissures and as filling of breccia zones. Cuprite, tenorite, melaconite, malachite, and azurite occur but are not abundant. Lying between the chrysocolla horizon and the primary sulfide is a transition zone whose limits are irregular but seldom with vertical range exceeding 50 ft. Chalcocite, cuprite, melaconite, native copper, and chrysocolla occur superimposed on the primary sulfides. Chalcocite replacement of chalcopyrite, as well as secondary chalcocite, do occur. The primary sulfide minerals are chalcopyrite and pyrite, with minor amounts of bornite and covellite. There are no appreciable gold or silver values, and molybdenite has rarely been noted.

Jan 1, 1985

By Brendan Howard

Rio Tinto has a large globally distributed technical workforce and needs to ensure these employees have the requisite skills to not only manage technical risk and enable safe efficient production, but also ensure they are keeping pace with a fast-changing technological landscape. Traditional approaches to learning struggle for scale and an inability to respond to the extreme diversity of capability development needs. In response, Rio Tinto has successfully introduced innovative approaches to learning and employee engagement via leveraging the power of globally distributed networks for peer-to-peer knowledge transfer and providing mechanisms to recognise, reward and retain the individual technical contributors.

Feb 1, 2024

By Wei Victor Liu, Na Zhang, Chengkai Fan, Bei Jiang

This study used artificial neural networks (ANNs) coupled with Gaussian mixture modeling (GMM) to analyze truck haulage data from openpit mines. The proposed weighted ensemble models performed better than benchmark models in predicting truck productivity, providing a new means of solving complex data and improving mine planning and decision-making.

Jun 1, 2023

By S. Frimpong, E. Gbadam, W. Nyaaba, G. Somua-Gyimah

Recent studies towards dragline excavation efficiency have focused on incrementally achieving automation of the entire excavation cycle. Initial efforts resulted in the development of an automated dragline swing system, which optimizes the swing phase time. However, the system still requires human operation for collision avoidance. For full dragline autonomy, a machine vision system is needed for collision prevention and big rock handling during the ‘swinging’ and ‘digging’ phases of the excavation operation. Previous attempts in this area focused on collision avoidance vision models which estimated the location of the bucket in space in real-time. However, these previous models use image segmentation methods that are neither scalable nor multi-purpose. In this study, a scalable and multi-purpose vision model has been developed for draglines using Convolutional Neural Networks. This vision system averages 82.6% classification accuracy and 91% detection in collision avoidance. It also achieves an 87.32% detection rate in bucket pose estimation tasks. In addition, it averages 80.9% precision and 91.3% recall performance across terrain recognition and oversized rock detection tasks. With minimal modification, the proposed vision system can be adjusted for other automated excavators. Keywords: Surface mining, dragline bucket, deep learning, machine learning, oversized rock, convolutional neural network, machine vision, object detection, earthmoving equipment. INTRODUCTION Complete excavator automation is widely regarded as the next phase in efforts toward improving earthmoving efficiency. Earthmoving often involves complex, forceful interactions between an excavator and the ground. The nature of these interactions depends largely on the type, properties and physical characteristics of the earth material. This process is further complicated by the random occurrence of tree roots, boulders and other such obstructions. Therefore, the ability of a controller to detect changes in the operating conditions, adjust the digging strategy and respond in real-time is of utmost importance. Early studies into autonomous excavation identified some key performance criteria which included the following [1]: • The autonomous excavator must be able to work in any type of earth material. • Its excavation accuracy must be within 50mm. • It should be able to handle different surface and underground obstacles autonomously. • It should be able to operate at the speed of the average operator in any condition. • Its operation should be capable of safe integration with other site systems.

Jan 1, 2019

By Billy W. Parks

This paper reports on the first 2 years in operation of a special-purpose coal handling rig which provides blending, temperature reduction, and continuous, automatic mechanical sampling as part of midstream barge to ship coal transfers. Briefly reviewing some of the characteristics of coal handling peculiar to midstream transfers, the paper discusses how the most beneficial aspects of midstreaming were enhanced through the design of this blending and sampling rig.

Jan 1, 1986

By C. Sun

With complex component, higher salt content, low biodegradability, DSD acid oxidation wastewater could not be efficiently dealt with traditional methods. It is pointed that the coal water slurry could be made with DSD acid oxidation wastewater of different concentration and the density of coal water slurry could be up to 70%, while its viscosity is only 850~930 mPa?s. The coal water slurry could be perfectly jetted and burnt under different conditions. The higher density the DSD acid oxidation wastewater has, the better properties the coal water slurry have. The pollution components and characteristic group of DSD acid oxidation wastewater are similar to the additives of coal water slurry, so it could be used as a kind of usable additive of water coal slurry. It is so reasonable and feasible to make coal water slurry with DSD acid oxidation wastewater that the pollution of DSD acid oxidation wastewater can be solved completely.

Feb 23, 2014

By R. Hogg

A standard procedure for determining size-specific gravity distributions of fine coal (including the -400 mesh fractions) by sieving and centrifugal sink-float separation is described. The significance of using a centrifugal sink-float technique and the effect of the magnitude of the centrifugal force on the separation of fine coal are confirmed in the present study. The relative merits of cumulative versus incremental sink-float are discussed. The procedure is evaluated quantitatively using data obtained for the products of froth flotation of -100 mesh coal.

Jan 1, 1994

By EREN KOMURLUR, ATILA GURHAN CELIK, IBRAHIM GUNES

In this study, laboratory and site studies were performed to investigate the usability of a new insertion apparatus designed for the split-set type of friction bolts. The new apparatus decreases the friction during the bolt insertion by a temporary diametric compression of the split tubes. According to the results, the new precompression apparatus was found to be advantageous in terms of the insertion practicality and prevention of the buckling problem. By allowing increases in the ratio of bolt diameter to drill-hole diameter, the new apparatus was found to supply relatively high normal stresses and friction capacity in drill holes after opening its clamping mechanism.

By S. Tuylu, D. Adiguzel, A. Bascetin, O. Ozdemir, U. Cinar

"In recent years, use of mineral processing tailings as a paste backfill has been significantly increased due to the environmental problems occurred during the disposal of the tailings in mine area. The paste material used to fill the stopes excavated is generally consisted of tailings (solid ratio: 70–85%) and cement (3-7%w/w). Meanwhile, the strength of the paste material is completely related to ratios of these materials. Cemented Paste Backfill (CPB) system is used as support depending on the roof pressure and also as an underground disposal method. Therefore, temporary strength value of the paste material gains a great importance. For example, the paste backfill material must compensate the minimum 4 MPa strength value in order to procure the permanent fortification, and the mixture cost must be minimal as well. For this reason, in this study, the Pb-Zn tailings were used to prepare for the paste backfill material using cement in order to perform the uniaxial compressive strength (UCS) tests. Additionally, a statistical experimental design and linear programming techniques was used to find the optimum mixture in terms of strength and cost. The pulp solid ratios (PSR) of the tailings and cement (by the solid) were varied as 75-85% and 3-8%, respectively. The results of this study; the optimum mixture is ~79.5%PSR and 6.8% cement ratio (by the solid) for 4 MPa UCS (28 day) and 16-17 cm slump value determined by this method with statistically reviewed experimental data. INTRODUCTION Fine-grained tailing waste materials resulting from mining activities are an important environmental problem. In terms of environmental protection, the use of tailings with paste backfill is a very attractive approach and a desirable solution to tailings management. Paste backfill, which is used to fill underground openings, is made by primarly mine tailings mixed with hydraulic binders and water. Its main benefits are not only disposal of mine tailings in underground, but also providing a certain strength to ensure a safe working environment. Therefore, it is necessary to use hydraulic binders due to durability of the system (Benzaazoua et al., 2004). Paste backfill, formed from the mix of dewatered plant tailings (75-85 wt. % solids), water and binder (3-8 wt. %) (Brackebusch, 1994; Landriault et al., 2005).Water is used to determine the chemical reactions between tailing and binder materials for strength as well as increasing pumpability. Portland cement and ash can be used as binder materials (Douglas and Malhotra, 1987). The factors which affect strength and stability of paste backfill separate into two groups called interior and exterior factors. Interior and exterior factors determine the strength, stability and deformation features of backfill in short and long terms and also affect the transportation of backfill to underground (Benzaazoua et al., 2004; Erçikdi et al., 2006; Yilmaz et al., 2010; Nasir and Fall, 2010). Material properties of tailings as well as site operations to fill the underground openings are the most important steps for the design purposes. Grain size distribution, chemical, and physical properties of tailings, and mechanical properties of paste fill material are used to understand the suitability of tailings as paste fill material (Ozturk et al., 2014). In addition, Fig. 1. is also proposed to apply a typical design for the operational stages of paste fill applications on the site."

Jan 1, 2016

By J. Schoenbacher

Park City Municipal Corporation (PCMC), long before being recognized as an Olympic venue was known as one of the great American silver mining towns. During a century of active mining, the Park City mining district produced millions of ounces of silver in addition to a substantial amount of mine tailing waste. Since 1985 the City has been remediating these impacts with state and federal oversight. One particular challenging CERCLIS site, that was previously a historic mine tailings pond is known as Prospector Square Development (CERCLIS Listing Silver Creek Tailings UTD98051404). This site has been very challenging due to the metals that impact the shallow ground water that eventually drain into the Silver Creek Watershed. To address the water quality impairment the City and Missouri University of Science and Technology teamed up to investigate the feasibility of constructing a horizontal-flow wetland to treat this pollutant source. This effort began with the building of a pilot cell in June of 2004 and lead to the construction of a full scale horizontal-flow wetland in the fall of 2008. The design of the pilot and full scale biocell was based upon lab-scale research conducted by the Missouri University of Science and Technology. In October of 2008, the Prospector Drain effluent was introduced to the system and to date analytical results reveal that the biocell is treating the Prospector Drain outfall below the Silver Creek Total Maximum Daily Load (TMDL) endpoint goals for zinc .39 mg/L and cadmium .00075 mg/L. The water chemistry of the influent, that originates from the historic silver mine tailings pond, is impaired with zinc and cadmium and has low iron with a pH of roughly 6.5. The construction of this unit encountered many challenges related to constituent relations, regulatory scrutiny, constructability and start-up. Nonetheless, since implementation this unit is considered a success for improving water quality within the Silver Creek Watershed.

Jan 1, 2011

By Chien D. Ngo, Andre Bachmann, Rainer Bunge

The remediation of contaminated sites has gained great importance in many industrialized countries. One method for cleaning the polluted soils from such sites is "soil washing," the scope of which is the separation of the contaminants from the soil. Soil washing is an outstanding example for a successful transfer of technology from Mineral Processing to Environmental Engineering. This presentation intends to introduce the Mineral Processing Engineer to soil washing through a short review of the fundamentals, and the discussion of an example for a successful soil cleaning operation in Switzerland.

Jan 1, 1995

By Sidney A. Suhler

The persistent requirement for methods and equipment capable of detecting hazardous anomalies in advance of underground mining has led to the development by the U.S. Bureau of Mines of a directional radar probe. The probe operates from boreholes drilled from the surface into the underground region to be mined. The engineering model radar was completed in early 1982 and field demonstration tests were performed in May of that year at a selected coal mine. Preliminary in-situ electromagnetic tests were performed at several candidate coal mines to evaluate the radio-frequency characteristics of the coal. A coal mine in New Mexico was selected on the basis of low EM propagation losses in the coal and the presence of an extensive coal seam displacing fault as a radar target. The borehole radar was operated in two vertical boreholes which intersected the coal seam at approximately 25 and 40 feet from the fault interface. Radar reflections from the coal/ rock interface were detected in both tests. Underground tests in a horizontal borehole in the coal were less successful because of interfering reflections. Additional borehole-to-borehole tests were performed with a separate ground penetrating electromagnetic system to obtain radar range calibration data. The coal was found to be bounded by very lossy roof and floor sandstone and shale while propagation through the coal seam was obtained at distances up to 175 feet between test boreholes. Coal seam continuity was indicated by the hole-to-hole experiments through a section of the seam previously thought to be completely cut off by the fault.

Jan 1, 1983

By P. Guliov

In the first part of this paper the authors present an overview of industrial minerals produced in the Canadian provinces of British Columbia, Alberta and Saskatchewan, and supplied to the Pacific Rim countries. The second part outlines some of the unique opportunities for industrial minerals that exist in the three western Canadian provinces and those minerals we feel have development potential for overseas markets. Because of time constraints, it is not an exhaustive presentation on industrial minerals, but is focused on a few selected minerals that we believe have high potential.

Jan 1, 1990

By T. Diering

Gemcom PCBCTM is a software package which has been developed over the last 22 years for the planning and scheduling of block cave mines. This paper presents an update of the various research and development activities done to PCBC recently. It also provides an overview of the current capabilities of the software including tools for both feasibility type studies as well as tools for operating mines. PCBC is used extensively by prospective and operating block cave mines and some of the recent applications are described.

Jan 1, 2010