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By Oscar Morales

El presente texto describe el proyecto de expansión de producción de la mina Recuerdo a través del estudio de las estructuras, equipos, maquinarias y el personal que labora actualmente. En este sentido, el incremento de la producción se desarrolla por la mecanización del método de explotación, donde se utilizan los equipos LED Diesel y jumbo neumático Toyo ensamblado sobre ScoopHST-IA. El manejo del equipo optimiza la perforación en tajeos en un %50, a comparación de las perforadoras manuales. Asimismo, refiere el uso de la computadora para algunos trabajos en la mina como la preparación de informes mensuales, presupuestos y programas de producción anual para la División Mina.

Nov 8, 1984

By K. Bunney

A high-pressure laboratory elution rig was commissioned to simulate industrial Zadra and AARL elution conditions for the stripping of gold, silver and mercury from loaded activated carbon. It was found that cyanide was essential for the efficient elution of both mercury and silver, while gold was found to elute most effectively in hot, low-ionic strength solutions. Therefore, the standard AARL-type elution, which implements a cyanide soak and water elution, results in a lower recovery of mercury and silver from the carbon. No single set of conditions was found whereby gold, silver and mercury can all be effectively eluted in a single step. However, sequential elution conditions can efficiently recover all metals and provide a potential approach for separating these metals.

Jan 1, 2010

By L. R. Hougen

The Falconbridge Matte Leach Process yields high-purity nickel chloride by selectively dissolving nickel from copper-nickel converter matte with hydrochloric acid , purifying the solution by solvent extraction and crystallizing NiCl2 4H2O by further acidifying the purified leach liquor. In the Kristiansand Matte Leach Plant, a granular oxide is produced by high-temperature hydrolysis of the nickel chloride for subsequent reduction to a high-purity granular metal product, designated NICKEL 98. This paper describes the investigation of on alternate route to processing nickel chloride in which high-quality cathode nickel is produced by electrowinning from all- chloride electrolyte. The investigation was made in a pilot circuit containing two production-size electrowinning tanks operated in conjunction with the commercial-scale leach plant.

Jan 1, 1977

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Jan 1, 1907

By Dennis R. Dolinar

The danger to personnel, equipment, and pillar structure created by the spalling of a coal rib can be minimized by installing rib bolts. To assure that a configured support system will maintain a coal rib, the U.S. Bureau of Mines developed a rib bolt system based on a nonpreventable failure concept. A statistical equation quantitatively relates the amount of rib retained to the bolt spacing and the width of the spalled material. Laboratory test results show that the equation accurately predicts the amount of material retained and confirm the validity of the support concept. The examination of rib bolting at a coal mine experiencing rib sloughage provides evidence that the effectiveness of the support can be related to the failure pattern of the spalled material. An analysis of roof and roof support reaction to rib sloughage at the mine indicated that the rib sloughage had little effect on roof stability. Although supporting ribs might not affect roof stability, laboratory test results indicate that the material retained by the support can sustain a load up to 20 pct of the intact compressive strength of the material.

Jan 1, 2010

By W. Ivanick, Frank W. Glaser

ORDERING reactions of Fe-Si compositions in the a region have been mentioned in a number of review articles.7-8 However, little is known in regard to the critical temperature, T at which this transformation takes place. Greiner and Stoughton,' in a study of the constitution of iron-rich Fe-Si alloys below 800°C, placed the onset of order at a composition of about 4 to 5 wt pct (7.5 to 9.5 atomic pct) Si. They observed that at this composition the ductility and strength begin to decrease sharply and brittleness develops. During X-ray studies they observed only the appearance of superlattice lines for compositions containing 12.5 atomic pct Si. More recent X-ray diffraction studies- etected the appearance of superstructure lines (corresponding to the calculated positions of [Ill] and [ZOO] reflections) for alloys containing 9.5 atomic pct. This fact confirms Greiner and Stoughton's original hypothesis in regard to the onset of order at compositions containing about 7.5 to 9.5 atomic pct Si. The physical properties.of Fe-Si alloys containing more than 10 atomic pct Si have been studied only to a limited extent. Their extreme brittleness and difficulties of sample preparation render them of little industrial use in comparison with alloys in the 0 to 10 atomic pct Si range. The properties of Fe-Si alloys reported to date are mostly properties measured at room temperature on ordered compositions It appears that because of experimental difficulties fully disordered alloys could not be produced in the critical composition ranges and their properties could therefore not be reported. In Figs. la, lb, and lc, a summary of physical properties of Fe-Si alloys, measured during recent investigations of the influence of silicon additions to iron, is presented. No mention of determination of the critical temperature, T for disorder could be found in the literature. The following is an account of work done in an attempt to: 1) produce the disordered state of various Fe-Si alloys and establish the critical temperature, T for disordering, and 2) compare the electrical and thermal conductivity characteristics of the ordered and disordered phases as functions of composition. Materials, Preparation of Test Samples, and Testing Methods Fe-Si alloys with high silicon contents (about 10 atomic pct) are usually prepared using powder metallurgy techniques. This method insures accurate compositions and high purity through the use of protective atmospheres during solid state diffusion alloying of the mixed powders."" Iron and silicon powders were mixed in the desired proportions, cold or hot pressed, and then homogenized at 1150°C for periods ranging from 6 to 12 hr under a protective getter and in a hydrogen atmosphere. Fully homogenized samples were quenched in water from various and successively higher temperatures to establish the critical temperature for disorder. Temperatures were determined using Pt—Pt-Rh thermocouples in contact with the test samples. Test bars were approximately 0.6x1.25x7.5 cm. Electrical measurements were made at room temperature by determining the potential drop over a 1.5 cm span for a current of 10 amp. Densities of the samples were determined by immersion. High temperature electrical resistivities were measured using previously described techniques.'" Specific heat conductivity up to 200°C was measured by heating one end of the test bar and water-cooling the other; heat conductivity was then obtained by subtracting the rate at which heat entered the water from the

Jan 1, 1957

By C. D. Stahl, S. M. Farouq Ali, W. E. Culham

One- and two-dimensional mathematical models have been developed that simulate transient, two-phase flow of hydrocarbon mixtures in porous media in a manner that accounts for interphase mass transfer. Numerical simulations of one-dimensional depletion-drive experiments using a two-component hydrucarbon fluid were used to establish the validity of the mathematical models. In addition, the experimental and numerical data were used to demonstrate that production rate had a relatively insignificant effect on the recovery of individual hydrocarbon components from the experimental system, and that attainment of equilibrium between phases is possible for a wide range of liquid and vapor velocities in reservoirs containing light hydrocarbon fluids. Results of some two-dimensional numerical simulations are also presented. INTRODUCTION This study was undertaken to develop a mathematical model that would simulate transient, two-phase flow of hydrocarbon mixtures in porous media under conditions that result in interphase mass transfer and to test the validity of the assumptions used to set up the model. In addition, the study was designed to determine if production rate influences the recovery of individual hydrocarbon components from reservoirs producing by depletion drive. Two-phase flow in porous media, with interchange of components between the two phases, is important in many petroleum recovery processes. Studiesl-5 conducted within the last 3 years have outlined methods of solving multiphase flow problems incorporating mass transfer. Some of these studies have also indicated the importance of accounting for mass transfer under various producing conditions. An earlier work6 first demonstrated the importance of combining relative permeability data with equilibrium ratios in compositional balance methods. The mathematical model presented in this paper is formulated so that a phase behavior package, as described in previous papers,5,17 is not required as an integral part of the routine employed to solve for the primary dependent variables. The finite difference formulation is designed so that all the primary variables can be solved for simultaneously. This is accomplished by utilizing one basic set of equations. These innovations, which are in contrast to other models2,3,5 but are similar in some respects to the approach used by Taylor,l render the total problem computationally simpler than any of the previously referenced formulations. The mathematical model was developed by combining Darcy's law with a continuity equation for each hydrocarbon component. The principal assumptions invoked in the formulation were (1) that capillary forces and diffusional effects are negligible, and (2) that thermodynamic equilibrium exists in the reservoir at all times. No assumption as to the type of vaporization process was made in formulating this model. Experimental data were required to complete this study. These were generated by conducting several depletion drive experiments. The experimental apparatus consisted of a sandstone core enclosed in a pressurized casing. The apparatus was designed in such a manner that the core could be charged with a liquid hydrocarbon mixture and depleted at different production rates. The experimental tests were designed to determine the effect of production rate on component recovery. In addition, direct comparison of experimental and mathematically predicted

Jan 1, 1970

By R. J. Pugh

The surface chemical sites on several fillers (quartz, feldspar, calcite and granite) were studied by the adsorption of well defined acid and basic probe molecules (benzoic acid, benzyl alcohol, ethyl benzoate, pyridine and benzyl amine) from cyclohexane. The results provided a wide variation of adsorption data, emphasizing the extensive range of site heterogeneity on the filler surfaces. In addition, it was shown that the acidic probes were strongly adsorbed on all of the minerals, thus indicating that the basic surface sites dominate the acidic ones. Also, through FTIR studies with vapor-phase probes adsorbed on orthoclase, it was possible to identify the nature of specific sites and the type of bonding occurring between the filler surface and the probe molecule. These types of surface analytical techniques could give useful information for predicting the adsorption functional groups on dispersants, dyes, thickeners, etc. and could lead to enhanced interfacial bonding between the filler and the matrix.

Jan 1, 1993

Continuous remote sensing of air speed In underground mine airways. Approach An ultrasonic technique measures a form of air turbulence which is proportional to air velocity. How It Works The stainless-steel enclosed transducer consists of a sensing head with circuitry, and a telemetry card. The sensor uses a patented ultrasonic technique to measure a form of turbulence created In the air. This turbulence, known as vortex shedding, is related to the air speed through the sensor. Air flowing past a cylindrical post creates vortices which flow down the air stream on both sides of the post. Pulses from an ultrasonic transmitter pass through the vortices to a receiver; the effect of the vortices on the pulses is a measure of air velocity. The transducer contains a telemetry card, known as an accessor, which transmits reports on air velocity through a pair of wires to a monitoring system. The accessor contains an analog-to-digital converter and digital telemetry circuitry required for computer system operation. The transducer does not contain any read-outs or alarms and air velocities are displayed by means of a centrally located

Jan 1, 1982

By John Zeni

In Australia during the 1990s, Zeni Drilling took on several demanding shaft boring contracts. This paper describes the safety, operational, technical and environmental advantages derived through the implementation of mechanized boring methods for two of these projects. The paper first describes a 3-meter (10 ft) diameter access shaft blind bored from an underground location to 440 meters (1,444 ft) deep for a gold mine in Tasmania. The construction of a 5.8-meter (19 ft) diameter, 515-meter (1,690 ft)deep ventilation shaft for a longwall coal mine in New South Wales is also described.

Jan 1, 2001

By V. Miller

C. Hertzler The difference of means of milling characteristics by rock and ore type is tested in a statistical manner in the paper. The null hypothesis being tested is that the sample means of two different populations are equal. It is assumed that the null hypothesis is true when performing the test. Because of this, acceptance of this hypothesis leads to the conclusion that the sample means of the two different populations are equal (or there is no significant difference between the sample means), not that the samples come from the same population, as the author asserts. Rejection of the null hypothesis leads to the conclusion that the sample means of the two different populations are not equal. A P value for this test is reported in Table 2 and is incorrectly identified as the probability that the two samples came from different populations. Actually, what was recorded was 100(1 - p) where p is the usual p-value. The usual p-value measures, on a scale of zero to one, the extent to which the data agree with the null hypothesis. It is the probability of observing a value of the test statistic (Z score) that is at least as contradictory to the null hypothesis as the one computed from the sample data (McClave and Dietrich II, 1982). The author makes no mention of the fact that were these tests to be conducted together, the chances of determining that the null hypothesis is not true when it is really true are increased considerably (Snedecor and Cochran, 1980). This is a multiple comparisons problem and should be dealt with accordingly. The usual methods involve adjusting the level of the individual tests. Table 2 reports an incorrect 100(1 - p) value in the comparison of concentrate grades for other rock types with .30 to .69 % Cu vs other rock types with .70 + % Cu; 86 % should be 98.6 %. Although the article can be criticized for poor data presentation and discussion of that data, the point the author makes regarding the use of these statistics in the ore reserve estimation process is well taken. It does not appear that inaccuracies in the statistical interpretations have hindered that usefulness. References McClave, J.T., and Dietrich, II, F.H., 1982, "Statistics," Dellen Publishing Co., San Francisco and Santa Clara, CA, 766 p. Snedecor, G.W., and Cochran, W.G., 1980, "Statistical Methods," The Iowa State University Press, Ames, IA, 561 p. Reply by V. Miller After reading Ms. Hertzler's comments, it appears that the differences noted were basically semantics. If the paper is ever presented at a math symposium, some changes will be needed. When deciding the best way to present the data to mining engineers and geologists, I decided that presenting the probability that the two sample groupings came from different populations (reverse to the Null hypothesis) was easier and would require less verbage to explain. Hence, the 100(1 - p) difference which was noted. Ideally, I would have preferred to give the recovery and concentrate grades, then comment which ones had significant differences. Unfortunately, Kennecott Corp. did not grant permission to publish the ore body's actual recoveries and concentrate grades. The conclusion is that there was, as expected, a relationship between the ore's geologic properties and the metallurgical properties, and by determining this relationship, the overall mineral model was greatly improved.

Jan 8, 1984

By G. G. Meyerhof

The paper reviews the state of the art of estimating the bearing capacity and settlement of pile foundations in sand and clay soils, including the effects of pile installation, scale effects of pile size and embedment and non-uniform soil conditions. The lateral resistance of pile foundations and effects of eccentricity and inclination of the load on the bearing capacity and movements of pile foundations in sand and clay are considered on the basis of some recent investigations.

Jan 1, 2010

By R. A. Sharma, F. D. Richardson

Manganese oxide acitivities and sulfide capacities have been measured at 1650°C in mixtures of MnO + A1203 and MnO + SiO2 - Al2O3. Sulfide capacities have also been measured at 165O0C for melts of MnO + SiO2, MgO + SiO2, MgO + SiO2 + Al2O3, MgO + MnO + SiO2, and SiO2 + Al2O3 and for crystalline CaO. The activity coefficients of the sulfides of manganese and magnesium have been derived where possible. It looks as though the activity coefficients of sulfides are greatest at compositions where the free energies of formation of the silicate mixtures have their maximum negative values. The amphoteric nature of alumina is reflected in the results for the binaries and ternaries in which it is present with silica. The limiting solubility of CaS in CaO at 1650°C is 6.3 x 10-4 mole fraction. THE activities of manganese oxide have been measured in a variety of silicate and aluminate melts by use of the equilibrium (MnO)slag = [Mn]pt .½O2 [l] and the experimental techniques described previously.' Sulfide capacities (CS = wt pct S (PO2/PS2)½) have also been determined in a series of melts, by use of an established method2 which exploits the equilibrium (O°) + ½S2 = (S") . ½O2 [2] If CS and the activity of a metal oxide are known in a melt, the activity coefficient of the metal sulfide can be calculated by use of the equilibrium constant K, for the pure phase reaction MO i ½S2 = MS + ½O2 [3] The activity coefficient of the sulfide is then given by the equation

Jan 1, 1965

By S. Suwansawat, D. J. Maconochie, C. C. Chang

This paper describes the overall delivery of the tunneling for the Mass Rapid Transit Authority of Thailand’s Chaloem Ratchamongkhon Line in Bangkok and the constraints provided by the alignment. Eight earth pressure balance tunnel boring machines were employed under two major civil works contracts to drive approximately33 kilometers of tunnel in soft saturated ground beneath the crowded streets of Bangkok. Responsibility within the contract for building damage provided an inherent control for ground movement arising form tunneling when the right of way was narrower than the influence zone. These limits affect the earth pressure balance requirements and permissible ground loss. The methods adopted to limit ground movements and deal with the various obstacles to tunneling influenced the design and operation of the machines. The challenges provided by the need to tunnel through numerous lines of piled foundations of canal bridges and overpasses crossing the alignment are described.

Jan 1, 2001

By G. Mucsi, J. Faitli, K. Bohács

"The authors developed an online tube rheometer to supplement a Netzsch MiniCer (Netzsch GmbH, Germany) stirred media mill in order to monitor online the rheological characteristics of the suspension and therefore the result of grinding during the process. Previously it was demonstrated that the above measuring system was working appropriately based on the preliminary tests. The product related stress model was applied for the evaluation of the grinding results. It was found that the suspension concentration and the change of the material properties during grinding, consequently the rheology strongly affects the grinding result, i.e. specific surface area, median particle size as well as specific grinding energy. The tested model limestone – water suspensions behaved Newtonian initially, then after a given grinding time their properties had changed and they become Bingham plastic. INTRODUCTIONStirred media milling now is a common practice to produce fine and ultrafine granular materials for different purposes. With an increasing demand of ultrafine powders for industries (Kwade, 1999), wet and dry ultrafine grinding has been increasingly used in various fields, such as minerals (Mucsi, Rácz, & Mádai, 2013)(Rácz, 2014), ceramic materials (Becker & Schwedes, 1999), pigments (Ohenoja, Illikainen, & Niinimäki, 2013), chemical products (Baláž et al., 2013), microorganisms (Kwade & Schwedes, 2002) and pharmaceutics (Afolabi, Akinlabi, & Bilgili, 2014). It is well known that suspension rheology affects the wet comminution of materials (He, Wang, & Forssberg, 2006a). The rheological behaviour of the suspension containing the ground particles might indicate the level of interparticle interaction or aggregation and therefore it is an important variable factor of the process control (Muster & Prestidge, 1995). The influence of the rheological behaviour of mineral suspensions on their grindability has attracted more and more interests and attention, especially on ultrafine grinding performance (He, Wang, & Forssberg, 2006b) (Bernhardt et al., 1999). However, there are still many issues concerning the machine and the process for the different applications. When grinding is effective and the particle size range decreases significantly, the circulating suspension is becoming typically non-Newtonian. The changed rheological behaviour and the increasing rheological material parameters can negatively affect the grinding efficiency; therefore it is an important issue. Ultrafine stirred media milling as well as solid-liquid two phase flow have been studied for a long time at the Institute of Raw Materials Preparation and Environmental Processing of the University of Miskolc. Regarding ultrafine grinding the research is focusing on the description of materials’ grindability (energetic aspects) both in wet and dry circumstances (Mucsi et al., 2013; Rácz, 2014). Concerning rheology, the three measuring pipes tube rheometer was developed decades ago (Faitli & Gombköto, 2015). So far many different solid materials from all over the world had been tested in this rheometer (Faitli & Gombköto, 2015). Main aim of these tests was to gain basic data for large scale hydraulic transport applications. Among the many stirred media mills there is a Netzsch MiniCer mill at the Institute. It was reasonable to combine the two fields together, and the goal of the research presented in this paper is to develop an online tube rheometer for the Netzsch mill and to carry out grinding and rheological testing simultaneously."

Jan 1, 2016

By E. W. Mehal, R. W. Haisty, D. W. Show

The next generation of integrated circuits will probably include circuits constructed in and of GaAs. The existence of both semi-insulating and semiconducting forms of GaAs is the fact which will bring this about. In this paper we discuss the uses and limitations of semi-insulating GaAs for integrated-circuit applications. The two main areas considered are the electrical isolation that can be achieved between components on a semi-insulating substrate and the characteristics of p-n junctions in contact with semi-insulating GclAs. A process basic to attaining integrated circuits in GaAs to fully utilize the insulating properties of the substrate is selective epitaxial deposition. This process involves the deposition of a SiO2 layer onto a The trend in integrated circuits is towards the use of high-resistivity substrates or regions to achieve component isolation. The use of SiO, layers in the oxide isolation methods and the use of sapphire substrates are examples of this idea. GaAs is also a polished surface of a GaAs substrate, etching out selected area of the SiO, film to expose a GaAs surface, and deposition only onto the exposed GaAs surface. By using this process , islands of semiconducting GaAs are deposited onto a semi-insulating GnAs substrate, the islands being electrically isolated from one another by the substrate. The deposition of both p- and n-type semiconducting GaAs can be carried out in this nzanner to form p-n junctions in the island areas. This process can also be used to produce a planav structure by deposition of GctAs through a SiO, mask into holes etched into the GaAs substrate. This Putterned Epitaxial Technology (PET) is described. very promising material for use in future integrated circuits because of the existence of both semi-in-sulating and semiconducting forms. Active devices can be fabricated in the semiconducting material, and these individual components can then be electrically isolated from one another by using semi-insulating GaAs as the substrate. Epitaxial semi-insulating GaAs can also be produced thus making three-dimensional monolithic integrated circuits feasible.' This paper describes the research aimed at developing the methods for producing both two- and three-dimensional integrated circuits in GaAs, and examines some of the properties of semi-insulating GaAs as they relate to these integrated circuits.

Jan 1, 1967

By Alexander Squire

A brief study of the effects of material and processing variations upon the tensile properties of steel formed from mixtures of iron and carbon was made in order to provide information regarding the properties obtainable in iron-carbon compacts as influenced by forming pressure, sintering temperature, and graphite particle size. Sintered steels formed from mixtures of iron and graphite have been studied by Stern,' who investigated the effect of various percentages of graphite on compacts formed from electrolytic iron that were repressed and heat-treated after sintering. A further study, by Stern and Greenberg,l is concerned with the heat-treatment of steels formed by the car-burization of iron compacts, and Margolies3 has reported work on the simultaneous sintering and carburization of iron-powder parts. Glauch4 investigated the effect of various types of graphite on the properties of iron-carbon powder alloys but did not determine the effect of different particle sizes of the same graphite alloyed with different types of powder. In the investigation reported in this paper, powders typical of those produced by electrolytic deposition and the decar-burization of shotted steel scrap were used. The powders were mixed by tumbling in a jar mill with graphite powder ground to an average particle diameter of 2, 4, 6, and 16 microns (as determined by microscopic measurement). The properties of the iron and graphite powders are presented in tabular form as Table I. In order to obtain the maximum information from a minimum number of test specimens, the study was divided into two sections with one set of specimens treated identically in each section as a basis for comparison. In the first section, iron powder produced by the shotting and subsequent decarburization of scrap steel was mixed with 2-micron graphite powder, pressed at 50,000, 100,-000, and 200,000 psi, and sintered in hydrogen at 1200°C for the periods of time ranging from 15 to 120 minutes. In the second section of the investigation, electrolytic iron powder was mixed with graphite of an average particle diameter of 2, 4, 6, and 16 microns, pressed at 100,000 psi, and sintered at temperatures ranging from 1000° to r200°C'. for periods of time of 30 to 180 minutes. By following this procedure an indication of the effect of the following variables upon the density and tensile properties of iron-carbon powder compacts was obtained: (I) forming pressure, (2) sintering time, (3) particle size of graphite powder, (4) sintering temperature, (4) type of iron powder.

Jan 1, 1947

By Brajendra Mishra

Molten Salt electrolytic processes offer unique opportunities to extract and refine metals where gaseous or metallothemlic reduction, hydrometallurgical extraction and aqueous electrolytic methods are thermodynamically constrained. Production of aluminum and magnesium by molten salt electrolysis are well known commercial processes. Several other reactive metals, such as lanthanides and actinides, as well as beryllium and calcium, make use of molten salt processing for extraction and refining. This presentation describes the science of molten salt chemistry and electrochemistry for winning and refining of several metals. In addition, recovery of metals from waste process salts by molten salt reduction as well as oxidation have been discussed. Material issues in design of molten salt reactors have been included. Various applications have been presented through case studies. Experimental data have been included to justify the suitability as well as limitations of these specific processes.

Jan 1, 2003

By M. MacLaughlin, J. Whyatt

A case study is presented that relates statistical descriptions of joint sets to the distribution of local wedge failures along the crest of a catch bench at the Yellowstone Talc Mine. The fracture sets and bench width were mapped by teams of geological engineering students from Montana Tech under the direction of Dr. Mary MacLaughlin. The students analyzed the fracture data, conducted physical property tests, and used a beta version of a NIOSH program “Bwedge” to predict the distribution of surviving bench widths. In the course of this analysis the students developed evidence of software performance issues that, unfortunately, frustrated their analysis. These have now been addressed and a full analysis completed. The analysis confirms the validity of the student mapping program and provides insight into the effects of blasting and excavation practices on the bench. It also provides a tool for exploring the pattern of bench crest failure that would result from variations in both bench geometry and blasting practices.

By William Gleason

Despite a global slowdown in most mining sectors, Caterpillar, the world?s largest mining equipment maker continues to forge ahead with new, and improved offerings to the global mining industry. On Nov. 10, as part of its Loading and Hauling Mining Focus Session at its Tinaja Hills proving grounds south of Tucson, AZ, Caterpillar unveiled to customers and media its two latest mining products, the 994K wheel loader and 6020B hydraulic shovel. The Caterpillar 994K wheel loader builds on a nearly 25-year history of the 994 model but with one noticeable difference ? the 994K is bigger ? much bigger. Weighing in at 239,142 kg (527,218 lb) the 994 K is up to 20 percent larger and comes with up to 30 percent increase in payload capacity. This behemoth of a machine is currently being tested at Caterpillar?s Tucson Proving Grounds, Anglo Gold Ashanti?s Cripple Creek and Victor gold mine in Colorado and Taseko?s Gibraltor copper and molybdenum mine in British Columbia, Canada.