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By Bernard Y. Saltie

The White Pine orebody is characterized by a high lateral stress or highly faulted and joined conditions. Because of these difficult conditions roof support has always been a main concern. Mechanical bolts were widely used in the early seventies; however, it became apparent that major improvements in ground control were required if safe operation at White Pine was to be continued. The first step was taken in 1973-1974 with the testing of resin bolting. Record of caves and roof-falls with either type of support demonstrated superiority of resin bolting versus mechanical bolting - Safety was dramatically improved which was the absolute first consideration; however resin bolting was still more expensive than mechanical bolting. In order to generalize resin bolt installation, the second step was therefore to acquire special roof bolters compatible with resin bolting. The machine was to enhance the safety of the operation. This was achieved by the acquisition of the Secoma bolting machine equipped with an automatic bolting turret. Being a "hands off" operation the safety of the operator is total. Using a fixed taped attachment of the drill steel on the chuck a front guide and an automatic regulator torque thrust on the steel drilling in small diameter was possible. Being a fully automatic process only one operator is required per machine versus two operators with the conventional machines. The two main objectives were reached enabling the extension of resin bolting to the whole mine.

Jan 1, 1980

By R. Y. Wan

Recent research efforts have shown have shown selective solvation extraction of a gold cyanide ion-pair complex from alkaline cyanide solution is possible with organic phosphorus esters. These alkyl phosphorus esters such as tributyl phosphate (TBP) and di-n-butyl n-butyl phosphonate (DBBP) can selectively load gold to rather high levels, even in excess of 30 gpl. However, traditional stripping techniques are not particularly effective. In this regard, gold recovery by direct electrolysis of the organic phase has been found to be an interesting possibility. Further, the rate of direct electrodeposition from the organic phase can be improved significantly by using an aqueous/organic mixture. Direct electrodeposition of sheet gold from loaded DBBP was successfully accomplished at a current density of 8x10 4 amp/cm2 and 55°C from such a two-phase mixture with the aqueous phase as the continuous phase. No appreciable degradation the DBBP was found after 5 cycles of extraction and, electrodeposition. Finally, the applicability of the process strategy for an industrial situation was demonstrated by the successful treatment of waste gold cyanide electroplating solutions.

Jan 1, 1986

By Y. H. Kim

A simulation procedure has been developed that realistically portrays aggregate growth and disintegration for particular types of floc structures in water and wastewater treatment processes. The procedure requires local dissipation rates and specification of an interaction distance between colliding particles. A principal difficulty encountered in polymer flocculation, however, arises from changes in conformation of adsorbed macromolecules. Therefore, in systems where polymer flocculation occurs by bridging, dynamic changes in the particle size distribution depend upon the interaction of nonlinear. stochastic hydrodynamics with particles whose growth results from a number of concurrent and sequential random processes.

Jan 1, 1988

By Y. V. Vasylchuk

An algorithm is presented for optimizing the classification of surface mine material subject to excavating constraints. High-resolution, expected-profit models are optimized to classification maps subject to site-specific excavating constraints. This optimization problem defies traditional closed-form analytical solutions. A practical heuristic algorithm quickly determines the optimum final destination for material subject to realistic selectivity constraints. The expected profit could be calculated from an estimated model if the value calculations are all linear; otherwise, simulation could be used. In both cases, a single expected profit for all destinations on a high-resolution grid is the starting point for dig limits optimization. Maximizing expected profit in a risk-neutral manner is correct given the repeated nature of grade-control decisions over relatively short timeframes.

By Y. Q. Lu

Efficient flotation of fine phosphate minerals from a deslimed waste phosphate stream (-74 microns) has been achieved by both bench-scale flotation and by flotation with a 2-inch air-sparged hydrocyclone (ASH) unit. A sample was collected from the waste phosphate slime stream at the SF Phosphate Limited Operations near Vernal, Utah, for flotation experiments at University of Utah laboratories. The collector used was a mixture of fatty acid, petroleum sulfonate and kerosene. Bench-scale flotation test results show that the minus 15-micron particles have a significant adverse effect on phosphate flotation. When the minus 15-micron material was removed by a classifying hydrocyclone, improved flotation recovery and concentrate grade were realized. A bench-scale flotation recovery of 86 % with a concentrate grade of 16% P2O5 was obtained from classified waste slime (74 x 15 microns) feed material containing 11.3% P2O5 In contrast, a 90% P2O5 recovery was achieved with a concentrate grade of 16-18% P2O5 by single-stage ASH flotation. With a second stage of ASH flotation, a concentrate containing 23% P2O5 was realized at an overall recovery of 75%. These results indicate that the industrial application of ASH flotation technology for phosphate recovery from waste slimes is promising.

Jan 1, 1995

By Y. J. Wang

This paper describes a procedure for solving the generalized system of n network equations in n unknowns considering the following ventilation variables and parameters: (a) air quantities, (b) pressure losses or gains caused by the control devices (i.e., fans or regulators), (c) resistance factors, (d) natural ventilation pressure, and (e) fan pressures (as a function of air quantities). The air quantities and pressure losses for all branches in the network are grouped into dependent and independent variables. The branches with an independent quantity are contained in a chord set, and the branches with a dependent pressure loss are contained in a chord set. In addition to the problem formulation, the solution procedure, applying the Newton method, is discussed and illustrated with a numerical example.

Jan 1, 1989

By J. D. Patsey

A computer program has been developed for use by the mining engineer for analyzing drum-type hoists prior to the modification of an existing system or the designing of a new one. Its use permits the preliminary evaluation of a system before seeking the technical assistance of mine hoist designers and manufacturers. Compatible with an IBM-PC, the user-friendly program accepts a variety of data and can analyze hoisting systems for any balance state. The extensive program can be used to: (1) calculate skip capacity to yield a desired production rate; (2) solve for required drum face width; (3) select a permissible wire rope from a menu of 50 available rope types: (4) estimate total horsepower of the hoist plant; and (5) estimate power cost. An example of the model's use in evaluating a hoisting system will conclude the paper.

Jan 1, 1986

By D. J. Tooker

For the next few minutes, I will be discussing a product and category that many people laughed at for years. The product is cat box filiers or commonly referred to by the brand name KITTY LITTER. This product was introduced in 1947 by Ed Lowe using the name KITTY LITTER. From 1947 to 1964 the product was sold mainly through pet shops. Starting in 1964, the grocery trade began to carry cat litters. From that point, the cate gory began a solid growth trend. Particularly in the '7O's, cat litter has experienced the same kind of explosive growth that has characterized the entire pet market. For example, in the twelve months ending 9/21/79, cat litter unit volume grew by 15% versus the previous twelve months. The basis for this explosive growth is easy to comprehend. The cat population itself is rapidly expanding, reflecting the changing life- styles of Americans. As famiiies grow smaller, there is room for a pet. As apartment and con dominim living shrinks living space, a cat fills the human need for animal companionship more efficiently. Table I illustrates current cat litter market factors and projects major trends into the future to conclude that the cat litter market will equal $205MM in 1985. With this dynamic growth defined, it was imperative that a company such as Lowe's that was totally devoted to the commodity-priced products, evaluate the opportunities for added- value product differentiation. This process was started approximately four years ago with a search for new cat litter products and other new product opportunities.

Jan 1, 1980

By Stephen E. Kesler

Carbonaceous sedimentary rocks are abundant in the upper part of the caldera or maar that hosts the Puebio Viejo Au-Ag district, and much of the Moore sulfide zone is in these rocks. These rocks are thinly layered and contain scattered plant remains and variable amounts of volcaniclastic debris and pyrite. The carbonaceous matter in the sediments yields no X-ray diffraction pattern and is not graphite. It has C/N ratios of 4 to 10, and &13C values of about -25 per mil, which indicate that it is dominantly of marine organic origin and partly degraded. Atomic S/C ratios in the unmineralized part of the carbonaceous rocks have a median of about 1.2, much higher than most similar unmineralized rocks, reflecting not only the abundance of pyrite in the sediments, but also the fact that the organic material contains several percent sulfur. Extracts from the organic material indicate that it is thermally mature and that it reacted with the hydrothermal solutions. Atomic S/C ratios in the mineralized carbonaceous rocks are generally higher than those in unmineralized carbonaceous rocks, ranging to values of 5 and more. These differences indicate that significant amounts of carbon were consumed by the reduction of sulfate and metal chloride complexes in the mineralizing fluids as they passed through the carbonaceous sediments. Direct reaction between organic material and ferrous chloride-bearing, acid-sulfate hydrothermal solutions probably caused continuous deposition of pyrite during this period. Intermittent deposition of gold from chloride complexes by the same reaction was probably facilitated by boiling or C02 effervescence.

Jan 1, 2013

By O. Porterfield, M. O’Kane, M. Endersby

BHP Iron Ore initiated research programs in January 1995 to develop long-term plans for decommissioning waste rock material at its Mt. Whaleback operation. More than 2 Gt (2.2 billion st) of waste rock were deposited during the past 30 years. Ultimately, a total of 4 Gt (4.4 billion st) will be deposited in waste rock dumps constructed near the open pit. The Mt. Whaleback operation is located in a semiarid climate adjacent to Newman, Western Australia. The primary research program includes the development of technology for the long-term performance of the waste rock dumps with respect to vegetation, slope stability, surface runoff, erosion and water infiltration. This paper focuses on the design and implementation of a cover system to prevent water infiltration to the underlying waste rock. Data obtained from a laboratory program and from soil-atmosphere modeling was used to design horizontal field test plots. The construction of the horizontal surface field test plots is discussed together with the field instruments installed to monitor performance. The cover system is designed to maximize infiltration during wet periods for subsequent evapotranspiration while minimizing surface runoff. The result is a near-zero net infiltration to the underlying waste material. An important feature of the design is the use of run-of-mine waste material as the cover material. Monitoring is in progress and will continue for at least two annual wet/dry cycles. The optimum cover system should minimize the net infiltration of water to the underlying waste rock while maintaining physical and ecological integrity for long-term performance.

Jan 1, 2000

By John W. King

reserves are exploring to increase them.. Uranium exploration projects are known to be active or planned also in Guayana, Colombia, Ecuador, Peru, Chile, Bolivia, and Uruguay in South America; in the UAR, Nigeria, Angola, Mozambique, Malawi, Kenya, and Somali in Africa; and in Greece, Iran, Pakistan., Indonesia, and New Zealand. The above list, to which several might be added makes a total of at least 43 nations actively interested in exploration for nuclear raw materials. As we consider the distribution of the world's uranium resources, it is interesting to note that roughly one third of the total occurs in deposits that are economically dependant upon another product. The very large reserves of South Africa could not be produced for uranium alone, but gold has carried a sufficient part of the total cost that uranium can be recovered profitably. Approximately 40 percent of the US reserves, or 120,000 tons, are estimated as by-product recovery from porphyry copper and phosphate operations, but these reserves are not presently in production. The remaining two thirds of the world's uranium reserves have been sought, developed, and produced primarily for their uranium content. Those deposits are estimated to contain 613,000 tons of uranium oxide recoverable at less than $10 per pound. Nearly half of that uranium occurs in unmetamorphosed sandstone hosts, mostly of late Phanerozoic age--the Colorado Plateau type. About 30 percent is contained in the quartz pebble conglomerates of southern Ontario, Canada, and 20 percent is in magmatic-related deposits--veins, contact deposits, mineralized breccias, etc.

Jan 1, 1969

By H. Y. Sohn

The paper discusses two processes, flash ironmaking technology (FIT) and moving-bed ironmaking technology (MBIT), which aim to reduce energy consumption and greenhouse gas emissions in the ironmaking industry by using concentrate directly without pelletizing and without using coke.

Aug 1, 2023

By Margaret Armstrong

The increasing cost of developing new mines and the need to mine more marginal deposits have led mining companies to use more sophisticated estimation methods such as kriging. But until recently, coal mining companies have shown little or no interest in these techniques. However, the stringent quality controls which are now placed on coal have led to a surge in interest in improved estimation methods. This can be seen from the -, number of research projects by private companies and governmental agencies on the application of geostatistics to coal reserve estimation. At present, most of these programs are centered on the problem of estimating the tonnage and the average grade (i.e. ash percent, sulphur content, calorific value, etc.) of the coal in-situ. See, for example, Sabourin (1975), Woods (1976, 1979), Pauncz and Nixon (1979) and Armstrong (1980). These studies show that the established techniques of linear geostatistics can be applied successfully to coal deposits. The study by Woods is particularly interesting because he had access to the actual production figures as well as the initial sample data from the no 2 seam in the Greenside Colliery owned by the Anglo-American Corporation. He showed that the estimates obtained by kriging were consistently closer to the actual production figures than those given by three other estimation methods. This confirms the superiority of kriging as a method of estimating block values for coal. Another advantage of geostatistics is that it can be used to determine the optimal spacing between drill holes. An example of this is given by Armstrong for the coking coal deposit in the Bowen Basin, Australia.

Jan 1, 1981

By L. R. Hossner

Chemical and physical properties of surface soils and overburden materials must be evaluated prior to strip mining activities. This information can be used to assess whether subsurface overburden can be equal in quality to the existing surface soils, especially when these soils are classed as prime farm lands. In Texas, materials from the Carrizo, Calvert Bluff, Simsboro, and Hooper Formations overlie the lignite. The Carrizo Formation consists of thick clean sands with poor water and nutrient retention capabilities. These materials are least suited for placement of the surface of reclaimed land. The oxidized, medium textured overburden from the Calvert Bluff and Simsboro Formations possess adequate water and nutrient properties and are better suited for sustained plant growth. Non-oxidized Calvert Bluff and Hooper sediments generally have acceptable properties for reclamation. However, caution must be exercised in vegetating these materials since they may contain acid forming sulfide minerals.

Jan 1, 1982

By W. Jacobi, B. Haider, D. Regulla, J. Huber

[Introductory Remarks] Thermoluminescence (TL) detectors are widely used for the dosimetry of X- and[ y]-rays. Also filter devices for radon daughter monitoring have been developed in which the a activity on the filter was measured with TL-detectors (Breslin et al., 1977). For this purpose normal LiF-tablets with a thickness of 0.4 - 1 mm were used. However the lower detection limit of such TLmonitors for radon daughters is relative high, especially in areas with a high [y]-background, due to the low [a /-y]-sensitivity ratio of such thick LiF-detectors. This [a/y]-sensitivity ratio can be increased if TL-detectors are used whose thickness is comparable with the range of [a]-particles. On the basis of this consideration we have developed a simple light weighted and sensitive TL-monitor for the measurement of the cumulative radon daughter exposure in air. [Description of the "Monitor] The monitor consists of two parts: The sampling pump with the accumulator, and the sampling probe which contains the air filter and TL-detector system. Both parts are connected with a plastic tube. For operation in mines a light weight, portable air sampler with a built-in accumulator (DuPont model 125 and 200, 400 g) is used which enables an adjustable, constant flow rate in the range of 7.5 -12 1/h. These air samplers allow a sampling period of 10 hours before recharging is necessary. For radon daughter measurements in houses this pump is replaced by a larger, netoperated pump with a flow rate of 180 1/h. Figure 1 shows a schematic cross section through the sampling probe whose weight is 40 g. The radon daughters are collected on a hydrophob membrane filter (Sartorius) with an effective filter diameter of 11 mm and a pore diameter of 3 µm; its collection efficiency for radon daughters is [>] 95%. Above the filter the detector system is mounted. It consists of two thin Tm-activated CaSO4-TL films of 8 mm diameter on a Al-carrier foil manufactured by Matsushita Inc., Japan. The thickness of the TL-film is 6 mg/cm2, which is comparable with the range of a rays. The first detector is faced in 3.5 mm distance above the filter; in addition to the ambient y background this detector is exposed to the [a] and ß radiation from the radon daughters on the filter. Between the first and the second TL-detector is an Al-absorber of 0.5 mm thickness which shields this detector against the [a] radiation and partly also to the ß radiation from the filter. Both detectors have the same [y] shielding. After air sampling both TL-detectors are read-out with a commercial, hot-air reader (Matsushita Inc. / Japan, Model 505 A). The glow-curves are identical for [a and y] rays (Regulla et al., 1980). The integral TLsignal from both detectors is displayed in mR-units (or mR-equivalent). The difference between the response of the unshielded TL-detector above the filter and the shielded TL-detector is proportional to the time-integral of the filter activity, integrated over the sampling period. Calibration and Intercomparison Measurements] The linearity of the a response was checked with a 241Am-source for an [a] fluence on the detector surface of 5400 [a's/cm2•s] in the range of 102 -105 mR-equivalent. Within the experimental error of 15% the response function is linear. The TLD-monitor was calibrated for radon daughters in air by comparison with a calibrated integrating, monitor (WLM-meter) equipped with a Si-surface barrier detector and a direct electronic read-out; this instrument was developed by us for area monitoring some years ago (Haider et al., 1976). The results of simultaneous measurements with the TL-monitor and the electronic WLM-meter in mine areas and in indoor air of houses are shown in figure 2. On the abscissa the mean potential [a] energy concentration (in WL) during the sampling period is given which was derived from the measurements with the electronic WLM-meter. On the ordinate the corresponding response of the TLDmonitor to radon daughters (difference between both TL-detectors) is displayed, expressed in terms of mRequivalent per liter sampled air. It follows from this comparison a linear relationship over the whole range of 0.005 - 5 WL with a standard deviation of 10%. The resulting calibration factor for the TLD-monitor is 18± 2 mRequiv per WL • 1.

Jan 1, 1981

By B. Das, D. D. Mishra, M. I. Ansari

Experiments conducted with a 75-mm-diem hydroryclone have shown it is possible to obtain an iron ore concentrate containing 60% Fe. 2.65% SiO2, and 4.0% Al2O3 from Barsua iron-ore washing-plant slimes. About 60% of the iron values are recovered from slimes containing approximately 49% Fe, 8.9% A1203 and 11% SiO2. The obtained products can be used in the sinter feed for iron and steel making. The key to achieving process success lies in establishing the correct cut point (d50) of the hydrocyclone through the manipulation of operating and design variables, such as spigot and vortex finder diameter, solids concentration and operating pressure. The cyclone efficiency is represented by the partition curve. The cyclone performance, evaluated mathematically from the reduced efficiency curve, is represented by the equation Y = 100[1 -exp(-axb)], where: •X = did 50, •Y = corrected of efficiency (%) and •a and b are constants.

Jan 1, 1994

By James M. Prudden, E. P. Jucevic

The Divide mining district occupies the center of a Tertiary caldera hosting the famous Divide silver lode and the crosscutting Gold Mountain mines. The northwest-southeast trending silver lode hosted ore with typically a 100:1 silver:gold ratio, high molybdenum content and argillic alteration dated at 16.5 m.y. within the Fraction Tuff. The east-west trending Oddie Rhyolite flow dome at Gold Mountain experienced possibly several periods of resurgence with repetitive silicification, brecciation and attendant precious metal deposition forming stockwork type mineralization. Silver-gold ratios average 10:1 for the mineralization phase of this 16.4 m.y. intrusive event. Similar chalcedonic mineralization registering a 3:1 silver:gold ratio cements conformable breccias within the Oddie Rhyolite basal flows unconformably overlying the Siebert Tuff on the northern flanks of Gold Mountain. Gray and red chalcedonic breccia matrix in the King Tonopah member of the Fraction Tuff contains a 50:1 silver :gold ratio.

Jan 1, 1990

By R. R. Fullerton

Diatomite or diatomaceous earth is composed of innumerable microscopic opaline skeletons of single-celled aquatic plants called diatoms. The unique properties of this material enable it to be used as an important filtration medium and filler. The Circumpacific contains several economic deposits of diatomite. The largest of these is located in Lompoc, Ca. This deposit is the world's largest, purest, and most uniform marine deposit currently being mined. The other Circumpacific deposits are of fresh water origin. These deposits and Lompoc's unique marine deposit are significant sources of the world's diatomite supply.

Jan 1, 1982

By Shailendra Chawla, Ashok Jaiswal, Sonu

Side spalling/skin failure occurs due to the high-induced stress in underground structures. In such cases, rock bolting or other support systems are being used to control the skin failure or spalling of the pillar. The nature of these support systems is passive, which acts during the deformation. These support systems restrict the displacement considerably of the side/or roof surface of the excavation. Ultimately, it improves the stability of the structure because of the increment in residual strength of rock mass. It is noted that these passive support systems give very low confinement in the range of 0–0.015 MPa at the onset of failure. As the level of confinement will be very low and dependent with progress of failure, triaxial test was not found practically suitable. Thus, an alternative procedure of testing has been proposed. In the procedure, sides of sample have been restricted little bit by using adhesive tape. It provides the limited boundness on the lateral direction (LBLD) of rock specimen. The uniaxial compression strength (UCS) test has been performed on 30 numbers of cylindrical rock specimens using the servo-controlled stiff testing machine. Specifically, two rock types (medium-coarse–grained and coarse-grained rocks) were studied in terms of stress–strain behaviour so that a full residual strength envelope for each specimen was obtained. This study reveals that the residual strength of limited confined rock specimens has been significantly increased as compared to unconfined rock for both groups of rock types. The average residual strength of LBLD specimens of fine-grained rock and medium coarse-grained rock has been increased around 12 times, and five times as compared to unconfined rock, respectively. The average peak strength of LBLD rock specimens has been increased in the range of 30.5 to 48.6% for coarse-grained rock. The results of this study have been presented in terms of peak strength, residual strength and Young’s modulus of rock, and the post-peak failure behaviour of rock specimens was also critically analysed through a stress–strain curve.

Mar 21, 2024

By W. G. Pariseau

Joints may be taken into account when using numerical modeling as an aid to mine design by embedding joints in the model. When using the popular finite element method, say UT3PC, a pre-analysis step is necessary, Step 0. This step is for the computation of equivalent properties of a representative elementary volume of jointed rock (REV) in the model. This Step 0 is taken before Steps 1, 2 and 3 for specification of a rock properties file, generation of the mesh, and model analysis are taken. A brief explanation of equivalent properties and several examples aid in explaining the details of Step 0. Focus is on procedures, input files, and output to show ease of computation. Theoretical details are relegated to references (e.g. Pariseau 2022). Comparisons of safety factor distributions about example mine excavations with direct scaling from mine observations then offer some insights concerning equivalent properties, especially strengths.

Feb 1, 2023