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By E. L. Litchfield

The electrification of ammonium nitrate-fuel oil (AN-FO) blasting agents by pneumatic loaders is described and discussed. The consequences of the electrification are considered in light of the initiation requirements of electric blasting caps. It is recommended (1) that semiconductive loading tubing be utilized and (2) that the resistivity of the AN-FO be controlled; it is further recommended that the operator (3) test to assure continuity of the electric detonator legwire-bridgewire-legwire circuit prior to insertion of the cap into charge or borehole, (4) keep the legwires shunted but not otherwise connected to ground during loading of the blasting agent into the borehole, (5) assure that the borehole is discharged prior to hooking up the detonator leads, (6) assure that he is himself discharged prior to handling the detonator leads, and (7) assure that the blasting cap leads are never carried to the AN-FO loader. The basis and significance of these recommendations are explained.

Jan 1, 1968

By C. Arthur Lefler

The hydrometallurgical processes for recovery of gold and silver in use at Round Mountain, Nevada and the practical aspects of the operation are discussed. Included are heap leaching by cyanidation, upgrading of solutions by adsorption of values on activated carbon and desorption (stripping) for electrowinning and subsequent refining steps to produce dore metal.

Jan 1, 1981

New Bio-Adsorber with Activated Carbon and Nano Tube Carbon for Separation of Nickel and Cadmium

Sep 13, 2010

The oxidation of sulphide minerals in aqueous suspension is discussed from several viewpoints. Limitations of our present knowledge are pointed out, and several points where further information would be of special interest are mentioned.Firstly, some properties of minerals and their effect on oxidation are discussed. Properties of different species, such as crystal structure, lattice bonding, and "metallic" properties are mentioned, and then the effect of variation within a given species is discussed. The effect of physical factors, especially particle size, is also considered. Other variables discussed include the importance of solution composition, and its effect on the nature and rate of reaction, and the use of various oxidising agents. Some factors concerned with the whole system, such as temperature, pulp density and stirring rate are then considered.Finally, the nature of various oxidation products is discussed with reference to the kinetics of reaction and the nature of the rate limiting step. It is suggested that more attention should be paid to electrochemical explanations of the reaction mechanism.INTRODUCTIONKnowledge of the factors governing the rate of oxidation of sulphide minerals in aqueous suspension is a prerequisite for the effective control of many ore treatment operations. Rapid oxidation of sulphides is usually desired during the leaching of sulphide ores and concentrates, but in the cyanidation of gold ores, or in the leaching of uranium ores, any oxidation of sulphides may be regarded as an undesirable side reaction. Knowledge of many of the factors involved is also of interest in connection with the oxidation of sulphides in flotation circuits and in natural ore forming processes.Systems for which some reasonably quantitative data have been published are listed in Table 1. Qualitative...

Jan 1, 1961

By H. A. Bilgin, G. G. U. Aldas

"Ground vibration is the natural result of the blasting process. Many empirical formulae and methodologies including analysis of travel path effects have been developed. The scaled distance, which is the most popular approach for the calculation of the attenuation of particle velocity in the ground, has led to significant advances in the prediction of particle velocity when both explosive charge and distance vary. However, this approach does not consider the effect of ground anisotropy and existence of structural geological features on ground vibration. Therefore, in this study, the effects of these rock mass properties on types, amplitudes, and frequencies of ground vibration waves at four surface mines are examined. The results, which were implemented at Kangal coal mine, Bastas quarry and Kíbrís quarry, provided guidance for the extensive study at Orhaneli surface coal mine.As a result of the study, the authors came to the conclusion that vibration amplitudes change depending on the ground on which sensors were deployed and the conditions depending on whether measurements were done near major structural geological features. It was determined that the vibration amplitudes, measured at equal distances from the source but in different directions, change because of the propagation velocity anisotropy. Besides the change of wave type due to the kind of ground at the measurement location, it was determined that vibration anomolies were due to structural features."

Jan 1, 2004

By Kerry Lahti, Bryan Ulrich

On Feb. 11, 2005, more than 20 mining professionals gathered in Elko, NV for a day-long round-table discussion on heap leaching. Attendees included project managers, operators and environmental professionals. They represented 10 mining organizations. Knight Piésold sponsored the special event. Its seven representatives included three staff members from the company’s Elko Operation, and one each from its Denver, Cajamarca (Peru) and Vancouver offices. The roundtable format was chosen to allow people from the mining industry to share ideas and experiences in an open forum. Rather than presenting prepared talks, spontaneity was encouraged. This resulted in a lively and enjoyable discussion.

Jan 1, 2005

By Carlos F. Perucca

"Potassium is one of the three basic plant nutrients along with nitrogen and phosphorus. There is no substitute for potassium compounds in agriculture; they are essential to maintain and expand food production.Potash is extracted from buried ancient evaporites by underground or solution mining. This accounts for most of the potassium produced. Another important source is brine from landlocked water bodies, such as the Dead Sea, Salar de Atacama or Great Salt Lake.About 95% of potash produced worldwide is used in agriculture. The rest is found in several other industrial uses, including glass manufacturing, soaps, plastics and pharmaceuticals.Currently, three producers: IMC, PCS and Agrium operate 8 conventional and two solution mines in Saskatchewan, five of which run froth flotation circuits, two heavy media-flotation, two run forced crystallization and one natural crystallization.Potash in SaskatchewanPotash was discovered in Saskatchewan in the early 1940’s while drilling for oil. The deposits lie diagonally across the southern plains of Saskatchewan sloping southerly from a 1,000m depth at Saskatoon to more than 1,600 m depth at Belle Plaine and up to 3,000 m in depth in North Dakota. The known deposits are massive, accounting for more than 40% of the world’s known reserves."

Jan 1, 2003

By David Van Horsen

Big Creek Tunnel 2, constructed in 1912, is located in the Sierra Nevada Mountains of California, east of Fresno. It is horseshoe and circular shaped with a 3.6m (12ft) diameter and extends 6.6km (4.1mi). Historically, tunnel performance suffers from highly jointed rock and low cover. In 2003, leaks were observed surfacing through outcrops of highly jointed graniodiorite, and subsequently investigated by visual inspection, joint mapping, ground penetrating radar, and a water-tracing survey. Several grouting targets were identified as a result of these investigations. Cement grouting was used to fill void spaces, broken rock and open joints expected to exist behind the concrete and steel liners. Project work consisted of grout hole drilling through the existing concrete liners, and grout placement through squeeze packers supplied by standard grout hose and portable grout plants. Grout pressures were typically 20?30 psi. Grouting was completed in 16 days with a total of 1,550 sacks of Type II/III grout placed at the three likely leak source areas. No grout was observed exiting the tunnel and the leak was stopped.

Jan 1, 2008

Automation in underground mining enhances safety and leads to economic efficiency. In the past many efforts have been made on the automation of longwall shearer operation. With respect to the ultimate goal of automation, ie self controlled operation, coal bed boundary detection is one of the key problems. For longwall human labor is necessary in order to detect the exact position of the coal seam to be excavated. The authors present a sensor concept based on infrared technology and pattern recognition which will solve this problem. The very harsh underground conditions set high demands on the implemented sensors. The combination of infrared sensors and powerful processing algorithms is part of the innovative concept for automation of the new Eickhoff Bergbautechnik GmbH SL 750 shearer loader. The multi-sensor automation system EiControlPlus which is designed for the complete detection of the machine environment fills in the gap in the coal-excavation automation by building a recognition system that turns the shearer loader into an 'intelligent machine' which is capable of detecting the correct position of the seam to be excavated and thus enables human-free coal mining.

Dec 6, 2010

By Chuck Edwards

Whatever your opinion of the validity of the scientific case for global warming, or of the wisdom of the Kyoto Protocol, it would seem judicious to err on the side of caution and try to sensibly minimize global climate change. To this end, we should take prudent steps to minimize our emission of greenhouse gases. Cameco is the world's leading supplier of uranium for use as fuel in nuclear power plants. Cameco’s uranium production fuels nuclear power plants in 16 countries. Nuclear power plants generate clean electricity without greenhouse gas emissions. This presentation describes the role that uranium and nuclear power can have in meeting the growing demand for electricity and at the same time combating global climate change.

Jan 1, 2004

By L. Simpson

South African is a repository of significant deposits of a variety of minerals. The Citigroup confirms this assertion with an estimate of in-situ valuation of US$2.5 Trillion. The mining sector plays an important role in the South African economy. In addition to the mineral resource base South Africa has other comparative advantages. Firstly, South Africa retains major mining companies that participate globally, including Anglo American, Goldfields and De Beers. Their global involvement offers much to the local mining sector and the broader economy. Secondly, government established research councils. The Council for Geoscience (CGS) was established to manage the Geological Survey of South Africa, including the reduction of geo-scientific investment risk. The Council for Scientific and Industrial Research (CSIR) promotes industrial development, including mining technology development. Mintek undertakes mineral research from mineral examination of ores, to extraction and refining technologies and manufacture of end products. Thirdly, South African universities teach and conduct research along the mineral value chain. They have increased their minerals graduates? capacity, thus advancing knowledge and skills. Knowledge and technical progress are behind productivity growth and emergence of competitive advantage. The research and development (R&D) capabilities of industry, science councils and universities, working in unison, will enhance the competitiveness of the South African mining industry. The National System of Innovation (NSI) requires multi-disciplinary, collaborative research. Key R&D elements, including skills and expertise, funding and facilities, must be available to implement a long-term national strategy or programme. Improved international collaboration and partnerships between government, academia and industry driven human resource development (HRD), ultimately develop the critical mass for inter-generational skills requirements. This trend requires an expansion of research collaboration programmes. Decisions involving investments and collaborative actions pertaining to R&D in the sector necessitate an analysis of the South African mineral value chain R&D capability. This paper analyses the evolution of R&D capability from exploration to refining, tertiary education, science councils and industry. The political economy of the evolution of this capability is analyzed in relation to the central role that the South African government plays in creating an appropriate supporting environment and related initiatives to enhance R&D and innovation. Keywords: research and development (R&D), science councils, universities, industry, innovation policy, South Africa

Sep 1, 2012

By M J. Kindley

The Golden Cross Gold Mine Project is now fully operational and into its second year of operation. Because of its location in the sensitive Coromandel Peninsula , strict water management and environmental requirements had to be met. This led to the development of new technologies for cyanide recovery and the adoption of advanced water management and water treatment systems. This paper discusses the water management and treatment system adopted for contaminated water at Golden Cross and provides data on the operational history to date.

Jan 1, 1993

"TREVIICOS CorporationINTRODUCTIONThe Walter F. George lock and dam was constructed on the Chattahoochee River between 1955 and 1963 with the double function of improving navigation and generating power. Its 82 ft. by 450 ft. (25m x 137m) lock can accommodate large barge traffic and its four generating units with a plant capacity of 150 MW have an average energy output of 453,000 MWH. The dam consists of a 1,496 ft. (456m) long concrete structure housing the spillway, a non overflow portion, the power units and two earthen wing dams extending to the Georgia and Alabama sides, respectively 5,810 feet and 6,130 feet long (1770m and 1868m). As soon as the reservoir was impounded it became apparent that excessive seepage was occurring. From 1962 to 1985 a series of remedial works was performed using several techniques, but the problems continued under the dam, jeopardizing its generating potential and possibly undermining its stability.Finally, the decision was made to construct a deep cutoff primarily under the concrete portion of the dam to remedy the problem. PROCUREMENTOn July 5th, 2001 best and final offers were solicited by the Corps of Engineers (COE) for the construction of a deep cut-off to be built in front of the concrete portion of the dam from the bottom of the lake and tied into it. The cut-off had to cross an existing lock structure and an underwater retaining wall, as well as the remnants of a steel coffer cell left in place from the initial construction.The specifications required that the wall be built with a minimum thickness of 24” (600mm) and that it extended from the bottom of the lake to elevation -5 (1.52m) into the Providence formation, an impervious layer.While the land portions of the wall were on average 208 feet (63.4m) deep, the marine portion started from up to 90 feet (27m) of water and continued through different rock formations for another 100 feet (30m).Contractors were invited to propose their own method of constructing the cut-off and offers would be evaluated using several criteria, including technical, economical, organizational and experience.Three proposals were received and on August 14, 2001 an award was made to the Joint Venture (JV) of Treviicos and Rodio."

Jan 1, 2014

By Walter I. Paniagua

Drilled shafts and precast concrete piles were installed for the foundation of several structures in a reconfiguration project of a refinery in Minatitlan, Veracruz, in the Gulf of Mexico. The soils are alluvial deposits of flat land from the Coatzacoalcos River, which are embedded with layers of sand, soft clay, and peat. As part of a QC/QA program, load tests, both static and dynamic, axial and lateral, were performed. In this paper results of 32 axial tests are presented, in which typical load-displacement curves were measured at the top of the foundation elements; from the interpretation of these plots, data were recorded for ultimate side shear and in some cases for end bearing capacities, which are compared with the theoretical results of the final stage of the foundation design. The comparison shows that under allowable loads, side shear determines the bearing capacity of piles, even when the tip is embedded in a hard layer. Underestimation of the side shear is evident; therefore design criteria, as well as the methods used for obtaining soil parameters, should be reviewed.

Jan 1, 2007

By D. Bour, C. Nyikos, R. Curtice

Fire in a coal mine can be disastrous on many levels. In most cases, when a fire is detected, mining operations cease and all personnel are evacuated. Underground coal-mine fires are difficult to extinguish, can burn for a long time, and often result in an extended period of lost production. In a worst-case scenario, the mine is permanently sealed and abandoned, resulting in lost jobs, lost natural resources, and possible devastation of the local economy. In some cases, seals placed within the mine to isolate the fire could eliminate the need for sealing the entire mine and the subsequent extended delay in returning the mine to full operation. Previous attempts to place remote seals to extinguish mine fires in active mines have been largely unsuccessful. The West Elk mine experienced an underground fire in early 2000. The fire could not be accessed and extinguished from the active mine workings. A method of constructing seals remotely by drilling boreholes into the affected area was needed to help isolate and extinguish the fire. This paper describes the process by which remote seals were constructed that successfully isolated the fire and provided a means of extinguishing the fire by flooding the area with water. The period of lost production in the West Elk mine was considerably shorter than is typical in similar situations.

Jan 1, 2002

In a previous paper of this series (1) ,t it was shown that during the creep of single crystals of lead, deformation proceeded to some extent by means of slip on the octahedral plane. This was demonstrated by the formation of slip lines on the surface of the specimens. At first, a few broad bands appeared after a small amount of extension had taken place; then, as extension proceeded, more and finer lines made their appearance until the whole of the specimen surface was covered.The present paper deals with the process of deformation of the creep specimens as revealed by X-ray examination..By the use of this method, the changes taking place in the crystal structure can be observed.EXPERIMENTAL METHODThe method of preparation of the specimens, their size and the purity of the lead employed have been reported elsewhere (1). At frequent intervals, the specimens were dismantled from the test rack and X-ray back reflection photographs were taken. The specimens were so marked and set up on the X-ray machine that the same spot on the specimen surface was always examined.Copper radiation was employed, the tube voltage and current being 45 kV. and 25 m.a. respectively and the exposure time 2 hrs. The slit diameter was 1 mm.

Jan 1, 1941

By V. K. Kollipara

Air flow patterns in the face area of a room-and-pillar mining are critical for understanding the dust dispersion characteristics and for developing engineering controls. SIUC has previously performed a CFD study to analyze the airflow patterns in the face area when continuous miner is making a straight cut. Results from this study identified low air velocity and re-circulation zones in the face area and illustrated the significance of line curtain, and scrubber operation on the air flow patterns. This paper discusses similar analyses when continuous miner is making a right turn cut as it is considered to be the dustiest cut among all the cuts made to advance an entry through a crosscut. This paper presents results for box-cut development for a right hand turn x-cut. This paper also addresses line curtain advance and air leakage through the curtain on the airflow patterns in the face area for such a cut. Low air velocity and recirculation zones were identified by analyzing the velocity vectors.

Jan 1, 2012

By J. Engels

CODELCO is considering the implementation of high-density tailings management at the Chuquicamata mine in northern Chile for its long term disposal plan. To achieve this, CODELCO commissioned the design, construction, and operation of a 70 t/d pilot plant, fed by existing tailings. The testing programme was completed in May 2011, and consisted of laboratory rheological and characterization assessments, pipe loop testing, beaching trials, and analyses of deposition behaviour for solid contents ranging from 57?68% (w/w). This paper describes the characteristics of the pilot plant, the testing programme, the beach trial analyses, and the resulting beach profile predictions based on the stream power theory. CODELCO also used other predictive beach slope methods, such as the equilibrium slope concept, which are not discussed in this paper. The final beach profile for design will be selected after an expert analysis of all methods has been completed.

Jan 1, 2012

By E. Matinde, S. L. Msibi

"The robust nature of alumina refractory materials presents opportunities for their in-process reclaiming and re-use in non-critical applications. Virgin refractories can be substituted with different quantities of reclaimed materials without compromising the quality of the refractory products. In this study, the effect of reclaimed bauxite on andalusite-containing refractory castables for tundish applications was investigated. The recycled bauxite was formulated in different proportions to replace virgin andalusite in the castables. Standard tests were conducted to evaluate the physical, physicochemical, and thermochemical properties of the formulated products. Static corrosion tests were conducted using tundish slag in order to simulate the actual operating conditions. The results show that the standard flow behaviour, open porosity, and bulk density of samples containing up to 22 mass% reclaimed bauxite were comparable to those of the reference castable. However, high-temperature properties such as static corrosion at 1400°C and hot modulus of rupture at 1500°C indicated that there is an upper constraint to the amount of substitution. The study demonstrated direct potential savings of up to 10% when the reclaimed alumina replacement ratio was increased to 22 mass%. IntroductionAlumina-based refractories can be classified into low-alumina, containing less than 50% Al2O3, and high-alumina or bauxite, containing between 50 and 90% Al2O3. High-alumina refractories have widespread applications in high-temperature metal extraction processes due to their outstanding thermochemical and thermomechanical properties and stability (Rebouillat and Rigaud, 2002; Frulli, 2016). The typical chemical composition of refractory-grade bauxite consists of 85–90 wt.% Al2O3, 5–10 wt.% SiO2, 1–2wt.% Fe2O3, 3–4 wt.% TiO2, 0.4–0.8 wt.% CaO + MgO, and 0.20–0.8 wt.% K2O + Na2O (Nyoka et al., 2013). The thermochemical and thermomechanical properties of bauxite-based refractories rely principally on the conversion of the contained silica and alumina to the highly stable corundum (?-Al2O3) and mullite (3Al2O3· 2SiO2) phases (Rebouillat and Rigaud, 2002; Hill and Sehnke, 2006; Garbers-Craig, 2008; Frulli, 2016)."

Jun 1, 2019

The effect of microwave radiation on the processing of Palabora open pit ore has been investigated. Significant reductions in Bond work index are demonstrated for microwave treated samples. Reductions in work index were found to be sensitive to applied power level and method of application. After single stage magnetic separation tests, improvements in recovery of FeO were noted. However, these were curtailed by oxidation of the magnetite species as a result of continued heating. The effects of microwave radiation upon the recovery of copper after froth flotation were also quantified. Small initial increases in recovery of copper were note dafter microwave treatment. However, with prolonged exposure, recovery was found to decrease. Overall recovery of copper was not affected except for samples treated for extended duration. The influence of microwave treatment upon the conventional Palabora grinding circuit has been quantified with the use of USIMPAC software. Conclusions are made regarding the economics of microwave treatment for this ore. Keywords : Microwave; Grinding; Magnetic Separation; Flotation; Economic Analysis

Jan 1, 2000