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By Ernest Bohnet

Each mining operation is unique in some aspect ownership; ore body location, size, geometry, grade, mineralogy, hydrology, or geotechnical parameters; or constraints such as environmental regulations. However, all mining operations are alike in one aspect; the prime objective of any mining project is to maximize the return on the investment. This is the golden rule, or in the language of mining, the investor?s law of conservation. A mineral resource, by definition, does not become a minable reserve unless the mineral or minerals can be extracted economically (and legally). The three preceding sections have covered the various types of surface mining options. The choice of the most economic method is dictated primarily by the type of de-posit to be mined, the mining rate, and the physical characteristics of the deposit.

Jan 1, 2008

By T. H. Phillips

The Mission Mine is an open-pit copper mine located 18 miles south of Tucson, Arizona in the eastern foothills of the Sierrita Mountains. Mining is done on 40 foot benches using P & H 2100 shovels and 170-ton Terex trucks. Drilling is accomplished With two (2) Bucyrus-Erie 45R?s, one (1) Bucyrus-Erie 60R and two (2) Ingersoll Rand T-5?s. For secondary drilling. a Joy VCR-ISO truck mounted drill is used. The mine is currently operating 3 shifts/day, 7 days/week at 59,100 tons per day, with the mill receiving 28,500 tons per day. The management of the drilling and blasting program requires extensive record keeping in all phases of the operation. This is essential in order to evaluate different products and procedures.

Jan 1, 1988

By K. S. Olson

My reaction when first asked to present this paper was; "What could I possibly say that would hold the audience?s attention for 15 minutes? What could I offer that anyone familiar with the Nevada Barite Industry wouldn't already know?" Well, quite frankly I can't. The industry has certainly been anything but exciting for the past 10 years and, in fact, quite depressing. The challenge, for those few of us left in it, has been to keep it alive. At times it has felt like a doctor must feel with a terminally ill patient. All I can do is recap the past ten years, review the present state of the industry, and offer a few personal opinions and observations as to where I think we are headed.

Jan 1, 1993

By Patricio Zarate

Due to the intrinsic variability in orebodies, similar metallurgical behaviour of all material sent to the concentrator is expected to have some variability. Still some specific ores have anomalous performance which can severely impact on the concentrator’s production of metal, in this case copper. The study first will show the mineralogical characteristics of “usual ore” and of this specific “abnormal ore” which will have to be processed by the concentrator in the future. After that base conditions on both ores and flotation test procedure will be explained. Later the different alternatives tested regarding collectors and modifiers results will be compared. Finally, after discussing the different results with different reagents and considering operational variables of the concentrator, Floticor PD 702 is recommended to obtain the best copper recovery without increase in excess mass recovery.

Feb 1, 2025

By Raj K. Rajamani

In ball milling the rates of breakage vary primarily with the size distribution of powder in the mill. In wet grinding viscosity of the slurry varies continually as size distribution changes and hence the breakage rates change. In this study a simpler estimation scheme is used to determine breakage rates in batch grinding. Using an approximate solution to the batch grinding equation, acceleration and deceleration of breakage rates of all individual size classes is determined when the grinding environment is varied. Experimental results with limestone and copper ore show time-dependent breakage rates under both dry and wet grinding conditions. In general the breakage rates increase for coarse sizes and decrease for fine sizes with increase in the fines present in the mill. Such variations have strong implications in closed-circuit grinding.

Jan 1, 1991

By Paul Kents

The Canadian Javelin Limited Cerro Colorado copper-porphyry deposit in Panama, possibly the largest known copper-porphyry, contains between 1350 and 450 meter elevations, drill proven and probable ore in excess of 3.0 billion tons averaging 0.65% of copper equivalent. The deposit is located in the Central Cordillera Range, straddling the Continental Divide at 1500 meter elevation. Local topography is very steep. Accessibility is difficult, all logistics made by helicopter, and only recently a 52 km. road from the Pan-American highway was completed into the area. The deposit was discovered in 1969, and since then 75 shallow exploratory holes and 98 deep holes, the deepest 1340 meters, totalling 45,000 meters have been drilled. Deep holes were drilled at the corners of a regular rectangular 150 meter grid.

Jan 1, 1975

By Sergio Godoy P.

The Los Bronces porphyry copper deposit is located in the high Andes of Central Chile. Ore is mined from several tourmaline breccias and from an earlier porphyry. After years of experience in the geostatistical estimation of reserves in different zones of the ore body, we believe that success lies in considering the evaluation as an integrated process beginning with the analyses of the drilling density and sampling methodology, ending with the critically important reconciliation between the estimated and the actually extracted ore, in general, when errors or differences occur, focus is centered in the calculation stages of geostatistics. However, this paper demonstrates that all the evaluation stages are equally important and require the direct and continuous geologic input to ensure the best possible estimate within the frame of the geologic constraints.

Jan 1, 1992

By A. Kalmes, B. Dehler, D. Kopp

Nutrien has six potash mines in Saskatchewan and has been proactive in maintaining the integrity of their tailings facilities through ongoing assessment, design, operation, inspection, and monitoring. Nutrien commissioned a system inventory and semi-quantitative risk analysis (SQRA) of all dikes to further environmental stewardship at their potash facilities. The inventory assessed nearly 100 dikes; each dike was rated according to a probability and consequence factor and assigned a risk score. The risk scores were used to develop a risk matrix for each of the six sites and risk-response actions for each dike and segment. The inventories and SQRAs will help each site assess priorities for investigation and risk mitigation, if necessary. The study results will also help Nutrien refine corporate wide tailings governance standards and demonstrate compliance with various governance regulatory obligations.

Mar 2, 2022

By Steven W. Hunt, Steven B. Fradkin, Roger J. Maurer

During the 1980s and 1990s, twenty deep shafts were constructed in Milwaukee to depths from 85 to 91 m (280 to 300 feet) through soil and weak rock thicknesses ranging from 37 to 69 m (122 to 227 ft). Adjacent compressible soils, settlement sensitive structures and high groundwater levels required that shafts be constructed without dewatering. Contractors attempted several methods of ground support and groundwater cutoff. Significant problems developed during construction of 11 of the 20shafts. One shaft collapsed; groundwater blow-ins occurred at five of the shafts; and seepage caused unfrozen windows at three of the freezewalls. Ultimately, combinations of grouting and ground freezing were utilized to complete all of the shafts into bedrock. This paper discusses the main design and construction challenges experienced and the lessons learned.

Jan 1, 2003

By Greg Adel, Darren Thornton, Julius Krutschnitt, Toni Kojovic, J. Mark Richardson, Bryan Smith

Mine-to-Mill® optimization is a total systems approach to the reduction of energy and cost in mining and mineral processing operations. Developed at the Julius Krutschnitt Mineral Research Centre in Queensland, Australia, it attempts to minimize energy consumption through the optimization of all steps in the size reduction process. The approach involves sampling and modeling of blasting and processing, followed by computer simulation to optimize the operation and develop alternatives. The most promising alternatives are implemented, and sampling is conducted to quantify energy savings. In the current DOE-sponsored research project, the primary objective is to adapt the Mine-to-Mill® technology to the aggregates industry. The project is being carried out at two quarries operated by Luck Stone of Richmond, Virginia. This paper presents work conducted at the Bealeton quarry.

Jan 1, 2005

All coal preparation unit operations in which fine coal is handled depend to some extent on wettability of coal surface by water. The wetting results from interactions between the coal surface and water molecules that are determined by the composition of coal matrix (interrelated with coal rank) and heterogeneous constituents such as oxygen functional groups, mineral impurities and pores. The contact angle of water on an unoxidized, homogeneous coal hydrocarbon matrix is calculated to be 100o, and much lower values measured on real coal specimens result from contributions from the heterogeneous constituents. While the effect of wettability is critical in flotation and oil agglomeration, suppression of respirable dust, and coal water fuels, it has been shown to play a significant role also in coal flocculation with semi-hydrophobic and totally hydrophobic flocculants.

Jan 1, 1995

By Graeme Lyall, Oy Leuangthong, Clayton V. Deutsch

There are many variables to consider in the evaluation of nickel laterite deposits including the concentrations of nickel, iron, silica, and magnesia. These variables show complex relationships with each other such as mineralogical constraints, non-linear correlation, and heteroscedasticity. The complex multivariate relationship between the variables cannot be reproduced by conventional Gaussian or indicator geostatistical techniques. We introduce the stepwise conditional transformation method as a pre- and post-processing multivariate transform for the stochastic simulation of a nickel laterite deposit. Transformed data are multiGaussian and independent at h = 0; thus, cosimulation can be avoided after verification that variables are independent at all lag distances. Back transformation restores the features of the input multivariate distribution to the simulated realizations. The complex multivariate correlations are reproduced and sensitivity issues are addressed.

Jan 1, 2002

By M. Leduc, M. Backens, M. E. Smith

An emerging technology for sustainable development in mineral development, tailings co-disposal™ is a means to dispose of conventional mill tailings within the void space of a waste rock dump. This method, while not applicable to all tailings systems, can offer a significant reduction in short-term and long-term environmental liability, land disturbance, closure costs, and negative public image. The concept is to dispose of the tailings simultaneously with the waste rock or leach ore, controlling the ratio of tailings to coarse material such that the resulting dump is stable both physically and chemically. The resulting co-disposal dump can be as safe as a conventional waste dump. In the case of alkaline tailings in a potentially acidic waste dump, the acid production can be buffered or slowed.

Jan 1, 2004

By Majid Ataeepour, Ernest Y. Baafi

High level programming languages such ass C, FORTRAN and BASIC have been used in the mining industry to simulate truck-shovel systems. In addition, some special languages for simulation such as GASP, GPSS, SLAM, PROOF and SIMAN are commonly used. The most recent simulation system ARENA uses graphical modelling approach as well as animation notion. In this paper, the main elements of ARENA required to perform a truck- shovel simulation and to view the simulation results by means of the model animation are presented. The layout of the haulage system including shovels, trucks and dump sites was generated using draw tool in ARENA. All the components of the haulage system were represented by graphical modules. Animation tool was used to depict the performance of the haulage system as the simulation progressed.

Jan 1, 1996

By B. Ainsworth

The 1972 discovery of the Howards Pass lead-zinc deposit was the product of systematic regional geochemical surveys used to evaluate conceptual geological models for the metal-rich black shales of the Selwyn Basin. Motivation of personnel involved in all aspects of work was as critical a factor to the success as the existing corporate attitudes and infrastructure. Exploration programs were flexible but maintained a focus only on targets of sufficient economic potential to support operations in remote locations. Direct costs for the programs that lead to the discovery were in the order of $500,000 (Canadian 1972). Geological reserves today stand at over 500 Mt (511 million st) of 7% combined lead-zinc, containing a higher grade zone of nearly 10 Mt (11 million st) of 16% combined lead-zinc.

Jan 1, 1991

By P. Somasundaran, Brij M. Moudgil

All the major interfacial technologies encountered in mineral processing involve adsorption of surfactants and/or polymers. With the need for processing low grade complex ores it is imperative that conventional techniques such as flotation and flocculation be extended to meet the challenge of treatment of fines. Addition of surfactants or polymers is indeed not limited to the solid-solid separations but extends to particle size reduction in the form of grinding aids and dewatering operations as well. Although progress has been made in recent years to understand the science involved in various interfacial processes, more challenges and opportunities exist today than ever before in processing of the low grade finely disseminated ores. A brief review of the recent advances and the challenges in mineral processing, especially, those related to the interfacial technologies is presented.

Jan 1, 1989

By K. J. Stratford

The selection of a suitable mathematical function for the modelling of the partition curve for dense medium cyclones is discussed. Five alternative functional forms (based on three basic functions) are compared using data obtained in the course of an extensive experimental study of a 610mm dense medium cyclone. It is shown that, for adequately sampled tests, any of the functions may be used, although a function based on the Weibull distribution is shown to be most suitable. Where data are poor, all functional forms exhibit disadvantages, notably in terms of a reduction in precision of parameter estimation. This problem can be exacerbated by the complex numerical techniques required to estimate the parameters of a particular function. A set of ideal requirements for a performance function are presented.

Jan 1, 1986

By Roshan B. Bhappu

The extraction of gemstones, except for diamonds, continues to be a more or less handpicking type operation all over the world. However, considering the physical properties of gemstones such as density (sp.gr.), color, size, shape, luster, brilliance, reflection of light and the like in contrast to the relatively ‘dull’ physical characterization of the associated gangue minerals, it should be feasible to recover several gemstones using modern mineral processing techniques. This paper illustrates the unique physical characterization of several gemstones and suggests appropriate mineral processing techniques that could be used to recover these precious stones. Special emphasis is placed on the versatility of the Heavy Media Separation (HMS) process for processing of the gemstones. Finally, a few examples of commercially viable operations involved in the recovery of emeralds and rubies are presented.

Jan 1, 2005

By David M. Spatz

Team, as defined by Katzenbach and Smith (1993), is a small number of people with complementary skills who are committed to a common purpose, performance goals and approach for which they hold themselves mutually accountable. As the mining industry searches for new ore discoveries increasingly under post-mineral cover, the process of mineral exploration has taken us from prospector to geologist to multidisciplined explorer to multi-disciplinary team. Multidisciplinary exploration techniques have improved in terms of sensitivities and penetration and more than ever before each technique requires specialists with appropriate training and skills to process data and interpret results. To produce a quality product, specialists must collaborate openly and honestly in an atmosphere where the collective result takes into account the knowledge and expertise of each individual and the relationships between all pertinent data sets.

Jan 1, 1998

By K. Verghese, H. M. Lee, R. P. Gardner, K. Boateng

Results of work on the development of a phenomenological model for the continuous flotation process wing short-lived radioactive tracer techniques for determining model parameters is reported. A model that incorporates a flotation first-order rate constant and a residence time distribution based on the cross-flow finite-stage (CFFS) model has been derived and investigated. The short-lived radioactive tracer techniques and the nonlinear search methods necessary to extract the model parameters have been developed. The conditions under which all the model parameters can be extracted from a single radiotracer experiment are detailed and illustrated. A micro- computer-based unique data logging system has been designed, assembled, and implemented for collecting the necessary transient radiotracer data. Results are reported for a continuous laboratory flotation process for the two systems, mica ore and coal.

Jan 1, 1987