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By F. Tailoka

Bi was electrorefined from alloys containing 10-90 wt% Pb, together with Cu and Ag as minor impurities, in a basic cell and in a recessed-channel cell with 27.5:72.5 NaCl-PbCl electrolyte at 450-470 degrees C and 10 000-20 000 A/m2. The voltage in the basic cell was as high as 9 V, with some carryover of Bi to the cathode observed, whereas in the recessed-channel cell it was as low as 285-635 mV. Flow patterns observed in a room-temperature model indicated that the recesses provide both static liquid hold-up and good mixing of the alloy, enhancing cell performance in combination with the reduced anode-cathode distance of 0.90 mm. The purity of the resulting anode product is as high as 99.9%

Aug 1, 1995

By Martin H. Stanczyk

The Organic Act of 1910 established the Bureau of Mines and gave it authority and responsibility for conducting research on separation, recovery, and recycling of waste products and scrap generated by the mineral and metals industries and the consuming public.(1)1 It was apparent to our Nation's leaders even then that mineral resources, once mined, are irreplaceable and that the development of methods for recycling the values contained in wastes would be required to solve the problem of even¬tual scarcity, Estimates of the increase in per capita consumption of mineral resources in this country indicate that the consumption of metals, minerals, and fossil fuels by 1980 will be double that consumed in 1970 (2). The United States can expect to meet its future mineral needs in three basic ways: the first is through increased production of primary raw minerals; second by increasing imports from foreign sources; and third by recycling secondary materials and metals that were formerly discarded as waste. Rather than consider these

Jan 1, 1972

By G G. Paine, C V. B Cunningham, G Harries

The companies of the ICI Explosives Group have successfully used a wide variety of internal computer codes including BOBCAT, KUZ-RAM, ICRAX, XPLODE, BLEND, 3CRACK, MICBLAST, DETON, etc. In recent years the extensive experiences across ICI have been combined into a single compatible model engineered to worldwide technical service and customer needs for the prediction and assessment of blast results.

Jan 1, 1987

By T J. Grandfield

Paste fill has been used successfully at Henty Gold Mine for the past five years. It has allowed 100 per cent extraction of the orebody, stabilised poor ground and enabled wide sections and offsets to be mined safely. However, there are a number of inefficiencies in the current paste fill system. These include the low output from the drum filter, the addition of aggregate to the paste to compensate and the trucking of paste from the plant to the portal. These inefficiencies have increased the operating cost of the paste fill system and caused a number of operational challenges such as blockages and increased pipe wear. These challenges have been partly overcome by taking ownership of the paste fill process, improved quality control and better communication. Henty is currently developing two new orebodies, the Mt Julia and the Darwin and has an opportunity to build an efficient paste fill operation. This is likely to be a high density paste system without aggregate, either located above the new orebodies or located at the plant and pumped to the new site.

Jan 1, 2002

By E. McLaren, J. Sanftenberg, C. Cameron, H. Dello Sbarba

"A Ventilation on Demand (VOD) system has been optimized and maintained at Glencore’s Nickel Rim South Mine (NRS) in Sudbury, Ontario, Canada for the past seven years. The system monitors and controls air quality and quantity through real-time, dynamic automation of primary fans, secondary fans, automated airflow regulators, and air monitoring instrumentation with VentSim™ CONTROL, a VOD software. This paper will focus on the implementation of testing procedures and system maintenance methods. Overall, the results show a consistent reduction in energy usage.INTRODUCTIONThe Ventilation on Demand (VOD) system at Glencore’s Nickel Rim South (NRS) mine in Sudbury, Ontario, Canada, involves the control of two 2,980 kW centrifugal surface exhaust fans with Variable Frequency Drives (VFDs), three 335 kW vane-axial surface intake fans with VFDs, 21 automated airflow regulators, six automated dampers, seven automatic doors and 198 underground auxiliary fans with ON/OFF starters. Additionally, the system monitors airflow at 48 locations, carbon monoxide (CO) at 40 locations, nitrogen dioxide (NO2) at 21 locations, and dry bulb and wet bulb temperature at 21 locations. The VOD system is also integrated with a tagging and tracking system to modulate the ventilation system automatically and in real time according to the presence and position of the personnel and vehicles. The tracking system comprises of 75 vehicle tags with diesel status and hydraulic status (ON or OFF), 440 personnel tags, and 200 tracking zones. Finally, it also involves the configuration and updating of 55 level plan and interactive procedures and 24 daily scheduled events. NRS currently uses VentSim™ CONTROL, Ekahau Tracking and PI Datalink to control, monitor, and configure their VOD system."

Jan 1, 2019

By Y Peng, B Guo

In gold processing plants, the water from the cyanidation stages is treated to detoxify cyanide species and this recycle water becomes the main part of the process water. Despite the low concentration of free and weak acid dissociable (WAD) cyanides in process water, the recoveries of gold and silver is still affected during flotation, especially when gold and silver are associated with iron sulfide minerals. This is a case at the Hidden Valley (HV) Mine. In this study, the effect of free and WAD cyanides on gold and silver recoveries by flotation from the HV Mine was considered.WAD cyanide (WAD CN) was prepared by mixing sodium cyanide and copper sulfate at a cyanide to copper ratio of 3:1 dosed at different cyanide concentrations. It was found that both free and WAD CN depressed gold and silver and particularly iron sulfides in flotation. The depressed gold and silver recoveries were closely associated with the depressed recovery of iron sulfide minerals, suggesting that free and WAD CN may not depress the flotation of liberated gold and silver minerals significantly. It was also found that 10 ppm free cyanide completely depressed the flotation of iron sulfide minerals and WAD CN depression is probably through the WAD dissociation to free cyanide species (mainly aqueous HCN) during the grinding process, resulting from a decrease in pH. Thermodynamic calculation showed that 5.5 ppm free cyanide was released in the end of grinding at an initial WAD CN concentration of 50 ppm. This research provides a guideline to counteract the negative effect of WAD CN in the flotation of gold and silver minerals.CITATION:Guo, B, Peng, Y and Espinosa-Gomez, R, 2013. The effect of weak acid dissociable cyanide on gold and silver flotation in Hidden Valley Mine, in Proceedings World Gold 2013 , pp 341-346 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By Stewart W. Daniel

"Increasing labour costs, the trend to larger mills, the processing of lower grade ores and a diminishing sup-ply of well-trained and experienced mill operators contribute to the necessity of automating a grinding circuit. With sophisticated process control techniques, supervision of the mill line is reduced to an occasional inspection by the shift supervisor. Process operating decisions and/or adjustments are quickly and accurately performed by the electronic devices to be described. When the variables in the grinding circuit are stabilized using the sensors and controllers as discussed, the over-all grinding circuit is maintained at its optimum grinding load level, with ample protection against under-and overloading."

Jan 1, 1967

By X. P. Zheng

Barium fluorphlogopites were synthesized in the laboratory in order to investigate the effects of composition and crystal parameters on surface properties and floatability. The negative surface charge of mica is determined by the barium content, the crystal cell volume, the distance between layer structure and the Ba-O bond length. The higher barium content, the larger the cell volume and distance between the layer structure and the longer the Ba-O bond, the more negatively charged the surface is and hence the more easily adsorbed to cationic collectors. When an anionic collector (sodium oleate) is used, barium oleate forms on the mica surface and hence chemical adsorption occurs.

Jan 1, 1993

By F. A. V. Guimarães, A. M. Costa

"The moisture in sintering is a very important parameter for the performance of the process. It allows that the granulation takes pace in an efficient way making the water bridges between the bigger particles used as nucleus and the finer particles that perform the coating of those coarse particles. The formation of the micro pellets is extremely important to prevent loss in permeability of the bed in the sintering grate, avoiding excessive fuel consumption and producing a quality sinter. The aim of this project is to use some of the methodologies for determine the saturation degree on ores and coal to determine the optimal moisture for sintering. In the sinter pot grate series, 3 to 4 assays in a series of 10 are required to determine the optimal moisture for the process. The saturation degree curve test has shown that is really viable to use this technique to skip those tests and go directly to the series to determine productivity and the coke / anthracite consumption. In an industrial scale can be used to adjust the water addition in the conventional mixing methods used in the sintering plants to increase productivity in the process.INTRODUCTION Sintering Sintering is a high temperature agglomeration process in which iron ore fines are partially melted and bonded together using fluxes and a source of fuel, usually coke breeze. The agglomerated product, sinter, has improved metallurgical properties making it an ideal ferrous burden that enable the passage of hot gases in the iron-making blast furnace. The sintering process is normally carried out over three basic stages: granulation, ignition/sintering, and product sizing. In the granulation stage, iron ore fines (usually a blend of selected ores), sinter return fines, fluxes and fuel, and are mixed with water and micro-pelletised in a drum or disc before being introduced in the main granulation circuit. (Wang, Teng, & Wang, 2017)."

Jan 1, 2018

This paper details a brief history of the Australian gold industry from the 1980s gold boom to the present day, highlighting an industry characterised by innovation in plant design and junior companies prepared to "have a go", in contrast to the conservatism of many larger mining companies. Design flexibility, the innovation of new processes, the preparedness to exchange "process know how" and technology singularly differentiated the gold industry from other sectors during the 1980s to the present. The introduction of two stage crushing, semi autogenous (SAG) milling, and pebble crushing, mill innovations, carbon in pulp (CIP) and carbon in leach (CIL) and the North Kalgoorlie screen etc were all exciting changes in the industry.

Jan 1, 2011

By William H. Emling

With profitability pressures in heavy industry increasing, many producers are turning to predictive maintenance as a means of harvesting untapped value from their production assets. Corporations are losing their maintenance and processing core competencies through attrition. As capital budgets are being trimmed, manufacturers are consolidating operating units into fewer, more profitable routes. Maintenance functions, however, typically receive low priority when investment is made, since many companies consider maintenance costs as ?overhead?. Condition-based monitoring, integrated to Level I and Level II process inputs, is seen as the most cost-effective solution to the implementation of predictive maintenance strategies. This paper will review the evolution of preventive and predictive maintenance programs, highlighting examples of successful application of integrated condition monitoring.

May 1, 2001

By A. B. Cecala

It has long been known that ventilation is a cost-effective method to lower respirable dust concentrations in all types of mining applications. The National Institute for Occupational Safety and Health has been working on a number of different research techniques that use ventilation as a critical component to lower respirable dust levels at surface and metal/nonmetal operations in the United States. This article presents five such research efforts. The first research area discusses how improving the ventilation flow patterns in an iron ore mill facility lowered respirable dust concentrations by 31 pct throughout the primary grinding area. The second research area examines how respirable dust levels were lowered at a dimensional stone shop by using air cleaning units suspended from the ceiling. A third area discusses how improvements in ventilation at underground limestone mines lowered respirable dust concentrations. The fourth area examines how improvements in dust filtration and pressurization systems significantly impacted the air quality in enclosed cabs of surface mining equipment. The last area presents a newly developed clothes cleaning technique. This technique uses an air spray manifold to blow dust from a worker?s clothing in an enclosed booth, which confines the dust for capture and removal by a baghouse dust collector. These research areas represent an array of different control technologies to lower respirable dust concentrations. Ventilation is an integral part of these control technologies.

Jan 1, 2006

By Robert E. Barieau

In the design of plants to separate helium from natural gas , it is necessary to estimate the enthalpies of the various streams at various positions in the process . This Bureau of Mines report surveys the various methods that have been used to determine enthalpies and gives information on the organizations with such capabilities . The minimum information required for developing an enthalpy diagram is presented , and the relative merits of the various methods are discussed . It is concluded that methods that require no mass flow rate or energy measurements are to be preferred .

Jan 1, 1965

By A. Poor Zaeif Doost

With columns being installed in rougher section at Miduk Copper Complex, the rougher feed mainly reports to rougher-scavenger cells. To evaluate the efficiency of regrinding circuit, we conducted flotation experiments on samples of the feed and the products of the regrinding circuit. The grade difference of these products at 85% recovery was considered as the efficiency index. Results show that, with weight recovery of the rougher-scavengers the efficiency of the circuit increases. Exclusion of the rougher-scavenger concentrate from the feed to the regrinding circuit, resulted in an increase in the efficiency index from 10.12 to 17.6%.

Jan 1, 2012

By Pancho J. Garza, Keith H. Dahlen, Chris A. Labye

"Design for reconstruction of the East Flagstaff traffic interchange project located in Flagstaff, Arizona posed particular challenges. The proposed design included construction of a nearly 50-foot tall mechanically stabilized earth (MSE) wall given rightof- way constraints and soft subgrade soils. The tight right-of-way, approximately 15 feet in certain locations, adjacent to existing structures limited the number of viable remedial alternatives to provide grade separation at the proposed bridge abutment without significant settlement. Preliminary analyses indicated the existing subgrade soils - consisting primarily of relatively soft silts and clays with decomposed pumice - would settle approximately 12 to 14 inches resulting in unacceptable wall deformation. Stone columns placed via vibratory methods (vibro-replacement) consisting of circular excavations which penetrate to firm bearing soils and which are filled with crushed stone were selected to densify the existing subgrade soils. The implemented mitigation measures helped limit settlement to less than one inch and allow for successful construction of the project. The project history - including site constraints, subsurface conditions, evaluation of remedial alternatives, stone columns methodology, and effectiveness of ground improvements - will be discussed.IntroductionThis paper describes the subsurface investigation performed for the reconstruction of the Business Route 40 (B-40) (Country Club Drive) and United States (US) 89 Traffic Interchange (TI) located within the city limits of Flagstaff, Arizona. This project is currently referred to as the East Flagstaff TI. The Project Site Vicinity Map is shown below.The former B-40/US 89 TI was considered ineffective in handling the current and projected volumes of traffic which transition from northbound (NB) B-40 to US 89 (both directions), as well as from southbound (SB) US 89 to SB B-40. The intent of the project was to reconstruct the TI to better accommodate projected traffic volumes. The project eliminated the existing ramps from both NB B-40 to SB and NB US 89. The new interchange includes a Tee intersection from B-40 to US 89. In order to accommodate this alignment, the profile of US 89 was raised several feet (on nearly the same as existing horizontal alignment) to match the elevated profile of B-40. B-40 was shifted just west of its current alignment to accommodate construction of a new, wider bridge structure which spans over Industrial Drive, the Burlington Northern Santa Fe (BNSF) railway, and old Route 66. South of the new bridge, B-40 transitioned back to the existing alignment just north of the I-40/B-40 TI. Within the project limits, both US 89 and B-40 were widened to three travel lanes in each direction."

Jan 1, 2015

By J. Vance Batty

Two methods were devised and evaluated for quantitatively measuring the amount of oleic acid on flotation products and in flotation waters. One method involved use of an organic solvent to remove carbon-l4-tagged oleic acid from mineral surfaces and flotation water phases with subsequent radio-metric analysis of the extracts. Studies showed this method to be slow and subject to large variations in accuracy and reproducibility. In the second procedure, tagged oleic acid was measured directly on the surfaces of dried mineral products. Oleic acid in the water phase was determined by adsorbing it on fine mineral, drying, and radiometric counting. Quantitative analysis of oleic acid on flotation products from bench-scale flotation tests with synthetic mixtures of ore minerals and quartz and with natural ores showed this method to be fast, accurate, and reproducible.

Jan 1, 1968

By Lang Tao, Jun Wang, Wei Xiao, Wenqing Qin, Pan Cao, Guanzhou Qiu, Key Lab of Biohydrometallurgy of Ministry of Education, Central South University

"The effect of metal cations on the rutile flotation using styryl phosphoric acid (SPA) as the collector was investigated by micro-flotation test, bench scale flotation test, zeta-potential measurements and adsorption measurements. The micro-flotation results indicated that Fe (?) and Al (?) ions in low concentrations had obvious activation on the rutile flotation, and Pb (?) ions in low concentrations had smaller activation of rutile, but Fe (?), Al (?), Pb (?), Ca (?) and Mg (?) have strong inhibition of rutile flotation in high concentrations. The bench scale flotation results indicated ethylene diamine tetraacetic acid (EDTA), boracic acid, and sodium hexametaphospate can decrease the metal ions concentrations, and increase the recovery of rutile flotation. Adsorption measurements and zeta-potential measurements revealed that Fe (?), Al (?) and Pb (?) ions were adsorbed on the rutile surface, and had interaction with SPA. But when these ions concentration were over the largest adsorption capacity, residual metal ions could occur chemical reaction with SPA.INTRODUCTIONRutile is one of the favored minerals for production of titanium dioxide white pigment, primarily through the chloride manufacturing process (Stanaway 1994; Hou et al., 2013) However, the majority of rutile ores belong to refractory ores, while flotation is one of the most efficient methods to separate fine rutile from gangue (Dolbear et al., 1937). With the flotation development, many effective collectors were successfully applied in the oxide ore. Many reviews have indicated that organic phosphonic acid collectors showed good selectivity on oxide ores such as ilmenite and rutile (Bulatovic & Wyslouzil 1999; Liu & Peng 1999).It is inevitable that many types of metal cations are present in ore pulp. These metal cations significantly influence the flotation of minerals. Liu et al. (2015) showed that Ca2+ and Mg2+ could improve the floatability of spodumene at pH 12.5 and 10.0, respectively. The authors proposed that Ca2+ and Mg2+ ions readily form hydroxy complexes (CaOH(l) and MgOH(l)) and precipitates as (Ca(OH)2 and Mg(OH)2) in strongly alkaline solutions. Fan and Rowson (2000) investigated the effect of Pb(NO3)2 addition as an activator on ilmenite flotation and showed that it could improve ilmenite floatability. The addition of Pb(NO3)2 resulted in an increase of ilmenite zeta potential in both weakly alkaline and acidic aqueous solutions. Mehdilo, Irannajad, and Rezai (2015) studied three kinds of ilmenite of different origins and discovered that both Mg and V had a negative correlation with ilmenite flotation, while the Mn content seemed to correlate positively with flotation efficiency. A number of studies have also showed that Fe3+ can improve the floatability of ilmenite (Fan et al., 2009; Nuri, Mehdilo, & Irannajad, 2014)."

Jan 1, 2016

The Xinglongzhuang Coal preparation plant project was a joint effort by American and Chinese engineers and for the most part designed to American standards. The plant owner and operator is the Yanzhou Coal Mine Administration, a division of the Shandong Coal Corporation. These are state owned companies which ultimately fall under the Ministry of Coal in Beijing. The new 3.0 million ton per year Xinglongzhuang mine is located in southern Shandong province in east-central China about mid-way between Beijing and Shanghai. This is an agriculture area, flat terrain, relatively dry climate with temperatures similar to Western Kentucky. During Confucius time (551-479 B.C.) this area was known as the state of Lu. Confucius home town of Qufu is about 20 kilometers to the north-east of the mine site.

Jan 1, 1989

By C. Gatlin, N. E. Garner, A. Podio

Experimental data from single chisel blows on Leuders limestone are presented. A pressure chamber, similar in design to well known microbit drilling chambers, was utilized to impose variorcs stress states on the sample. Confining pressure of zero to 10,000 psi and borehole pressures from zero to 5,000 psi have been used in the studies. Pore pressure was zero and the rock samples dry in all instances. Force-displacement records and visual examination of the craters indicate that the mode of failure depends on both confining and borehole pressure in certain ranges, ranging from brittle, through a transition, to near plastic. The mode of failure is reflected in the observed blow force and energy data, as well as the shape of force-penetration curves. INTRODUCTION A previous paper' presented initial data from the project on which this paper is the second report. While the first paper dealt with impact studies on synthetic rocks, the literature cited there is also pertinent to this paper, but will not be listed again in order to avoid needless repetition. This paper presents experimental data from single chisel impacts on limestone at certain simulated wellbore stress states. Specific variables investigated were combinations of borehole and confining pressure, crater geometry, a narrow range of impact velocity and the forces required to drive the chisel into the specimens under the varying conditions. EXPERIMENTAL PROCEDURE The same basic apparatus described in our earlier paper, except for the pressure vessel, was used in this study. Fig. 1 shows the complete experimental system. Fig. 2 shows details of the pressure cell, which is quite similar to the well known microbit drilling chamber. The confining (overburden) pressure system provides independent pressure control over the sample except for two, 21/4 in. diameter areas located on the sample ends. These two areas provide a pore pressure entrance on the bottom and a striking surface on the top where borehole pressure can be controlled. The ends are isolated from the confining pressure by O-ring seals. The borehole and pore pressures are related through the striking surface; they will be the same unless a seal is deposited on the borehole surface, either a mud cake or some other impermeable membrane. In these studies pore pressure control was not used, as the rocks were dry and unsaturated in all cases. Rock samples were prepared from 4-in. cubes as illustrated by Fig. 3. The circular disks of adhesive vinyl plastic protected the impact surface from the resin coating (Scotchcast No. 2) and were removed just prior to each test. This procedure insured a fresh uncontaminated surface for the impact. Fig. 4 shows the dimensions and loading of the sample, including the concentrations around the "borehole" periphery (O-ring seal). The rock used in this study was Leuders limestone, of Permian age (Leonard), quarried near Leuders, Tex. Geologically, Leuders limestone is a light gray, fossili-ferous limestone (oolitic foraminifera1 biosporite). Its fossil content is 80 to 90 per cent and consists primarily of calcitornellid, ostracods, pelecypods and oolites with the remaining part intraclasts. There are hematite or limo-nite rims on some of the intraclasts. The porosity is approximately 20 per cent, but the permeability is less than 1 md. There is no apparent orientation in the structure. Triaxial tests have been conducted to determine the variation of the physical properties of Leuders limestone in three orthogonal directions', and it is known to be unusually isotropic and uniform. Physical parameters for this rock are: uniaxial compressive strength = 9,700 psi; F = 32 and C = 2,700 psi; where + and C are Coulomb equation values (t = C+u tan +). Impact tests were run under the combinations of confining and borehole pressures shown in Table 1. Samples were dry with atmospheric pore pressure in all cases. Tests, in which elevated borehole pressures were applied, used a single layer of household Saran-Wrap to prevent horehole fluid invasion into the sample. This proved to be simple and reliable. The blunt wedge used in all the tests was 0.75 in. long and had an included angle of 60" with a 0.05-in. flat. In addition, a sharp 60" wedge was used for all confining pressures at zero borehole pressure. The chipper speed

By Xu Wang, Yizhe Zhang, Yangge Zhu, Xiao’ou Xia, Fangming Liu

"The progress of lean magnetite preconcentration in China was introduced in this paper, such as using coarse crushing to reject tailings, and multistage grinding, multistage magnetic separation. The applications of “more crushing and less grinding” process and equipment in lean magnetite preconcentration could reduce production costs effectively. The related analysis and study on concrete cases were carried out in this paper.INTRODUCTIONIn the case of the slowdown and weak recovery in the global economy, bulk commodity prices fell sharply in 2015. Take iron ore's prices for example, about 60% grade iron ore's import prices in China from about $65 per ton at the beginning of 2015 fell to about $42 per ton in the end of the year, down by about 35%. But iron ore resources are non-renewable resources, with the continuous development and utilization of mineral resources, high grade iron ore resources will be exhausted gradually. Accompanying with the economic recovery iron ore prices after this fall is bound to return to its value to maintain a high level.The development and utilization of resources is gradually turning to the low grade iron ore. Restricted by technical development level and disadvantages of lean iron ore resources, the cost of utilization lean iron ore resources is relatively high. Making full use of their rich lean ore resources has become many countries' important strategy to get rid of dependence on foreign countries' ore. Over the years with the development and progress of lean magnetite mineral processing technology in China, the production number of concentrator has been greatly improved.As the world's largest steel producer and consumer countries, ensuring a stable and continuous supply of iron ore is particularly important for the healthy development of China's iron and steel industry. Chinese iron ore production and import data in recent years are showed in Table 1.With the expansion of iron and steel production, iron ore demand has also been a phenomenal growth. Taking 2013 for example, China's crude steel production is about 780 million tons in 2013, accounting for about half of the world's total output of crude steel. At the same time, China is also the first major iron ore import countries whose iron ore imports in 2013 was about 820 million tons, an increase of about 10%. The degree of external dependence is very high. In some years, the cost of China's iron ore imports was even more than $100 billion, and second only to oil’s import cost in all bulk commodities."

Jan 1, 2016