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By D. R. Wilburn

This summary of international mineral exploration activities for 2006 draws upon avail-able information from literature, industry and U.S. Geological Survey (USGS) specialists. The summary provides data on exploration budgets by region and mineral commodity, identifies significant mineral discoveries and areas of mineral exploration, discusses government programs affecting the mineral exploration industry and presents analysis of the mineral industry based upon these data. Two types of information are reported and analyzed in this annual review. They include budgetary statistics provided by Metals Economics Group (MEG) of Halifax, Nova Scotia, and information on regional and site-specific exploration activities that took place in 2006 compiled by the USGS.

Jan 1, 2007

By William O. Rasmussen

Exploration requires processing highly varying kinds and amounts of geologic information. Successful discovery dictates that this be done quickly with maximum confidence. Most phases of exploration are more or less applicable to computer reduction on a routine basis. The use of digital computers to reduce raw data into interpretable form, lets the exploration geophysicist concentrate on interpretation and presentation, and to consistently apply more sophisticated and comprehensive analytical techniques, not practical before. In applying these concepts for the past several years, various efficient programs have evolved which provide more complete evaluation of all data including the pro- vision for more unique solutions. This has resulted in greater refinement and ability to select the most advantageous drill sites in a minimum time at a minimum cost or, in rejecting as soon as possible a project on which additional effort is no longer justified. Practical examples of computer applications in magnetics (air and ground), induced polarization and resistivity are discussed.

Jan 1, 1969

By James M. Harrington, A. Azra Bilgin, JoAnn Silverstein

The prevention of AMD in situ is more attractive compared to subsequent downgradient treatment alternatives that do not involve source control. AMD source control can be achieved by shifting the microbial activity in the sulfidic rock from pyrite oxidation to anaerobic heterotrophic activity. This is achieved by adding biodegradable organic carbon amendments to the sulfidic rock. This technique was applied in an abandoned mine pool with a pH of 3-3.5. Following treatment, near-neutral pH and decreased effluent heavy metal concentrations were achieved. In situ bioremediation by enhancement of bacterial iron and sulfate reduction is a promising technology for AMD prevention.

Jan 1, 2005

By W. Burger

Mechanical excavation methods can significantly improve excavation performance and labor safety compared to drill and blast operations. Herrenknecht has developed a mechanized shaft sinking method for soft and medium strength rock. This system combines innovative technologies which allow simultaneous excavation, removal of cut material and the installation of rock support. This Shaft Boring Roadheader ?SBR? is flexible in diameter and can be used in shafts with changing diameters and different shaft support requirements for depth up to 2,000 m. During regular excavation personnel are not required to access or work on the shaft bench. The boom used to cut the shaft profile is based on roadheader technology.

Jan 1, 2012

By S. G. Ozkan

Boron minerals of economic importance are primarily colemanite, tincal, and ulexite. Turkey and the United States are the leading producers of boron minerals and compounds. Other production includes datolite in Russia and synthetic colemanite in Chile. This paper will discuss various types of chemical and physical treatments of boron ores to produce the marketable minerals and compounds that are consumed in commercial products.

Jan 1, 1995

By T. M. Biddle

If an accident occurs at a mine, the mining company, its parent and affiliates, and its supervisory employees may face substantial -- and sometimes unexpected -- liabilities and costs. This presentation surveys the likely sources for post-accident exposure, including wrongful death and personal injury claims, mine closure/operational disruptions, and government civil and criminal actions against the company and its employees.

Jan 1, 1986

By G. C. Presley

With plant construction scheduled for the Spring of 1997, U. S. Zeolites will become the new source for quality in natural zeolites. The company will selectively mine, dry process, package, and market a very high quality clinoptilolite possessing many unusual properties. These unusual chemical and physical properties provide a multitude of industrial, commercial, and consumer applications. Extensive testing has determined many potential applications.

Jan 1, 1997

The CERAMEC pressure filter is used for the filtration of fine materials whose cake moisture cannot be achieved with vacuum. Development work has been carried out to achieve a well-controlled cake forming and cleaning of the filter media as well as an efficient solids discharge system. Operating costs are low due to low energy input and negligible consumption of pressurized air.

Jan 1, 1999

By Ethan Steward, Kyle Perry

The study investigates the effects of high-velocity impacts of common mine materials on a reinforced mine seal rated to 120 psi. It found that materials propelled during an underground explosion could generate enough stress to crack or damage seals, even with little visible damage. This highlights the need for careful evaluation of mine seals after any impact or high-pressure event.

Aug 1, 2023

By F. Habashi

It has been estimated that about 45 tonnes of mercury are emitted annually in the USA in the atmosphere as a result of burning coal in power-generating plants. A similar situation had existed in the metallurgical industry particularly in zinc production plants but this problem has been solved long ago by introducing scrubbing systems. Methods of mercury removal and recovery are discussed.

Jan 1, 2010

By A. Fleming

The exploration process, like any other commercial activity, can only succeed if the objective of the exercise is clearly defined and persistently pursued. Successful exploration requires properties, funding, personnel and persistence. Many of us have years of experience in conducting exploration in our countries of residence. Conducting exploration in a foreign country, however, requires a number of significant other criteria.

Jan 1, 1997

By Rudolf Fahn

Bentonites are best suited for the preparation of acid activated clays with efficient adsorption properties. They are weathering products of acid volcanic ashes and their natural deposits are world-wide spread. The main constituent of bentonite is the aluminium hydrosilicate nontmorillonite with a high ability to swell. Süd-Chemie owns bentonite deposits in Germany and subsidiaries in Italy, Mexico and Arizona.

Jan 1, 1979

By Paul F. Ziemkiewicz, John J. Renton, Thomas Rymer

Any viable model or deterministic formula used to make predictions must follow certain criteria. The standard models and procedures used to project acid load from mining activities operate from a number of assumptions, some of which, although logical, are scientifically oversimplified and, hence, invalid. Highly variable field parameters have lead to highly variable acid projections. Kinetic tests are in themselves misnomers in that no parameters associated with chemical reaction kinetics are ever determined. Sampling error coupled with assumptions made as to the distribution mode of pyritic materials in rock units can lead to highly inaccurate conclusions explaining why acid generation often occurs where none is predicted. The fact that probability theory and paradigms governing luck and chance have not been incorporated into the science of acid prediction undermines any credence placed on such projections. To date, with few exceptions, the acid prediction is logically closer to a game of chance than practical science.

Jan 1, 1991

By David R. Wayman

This paper summarizes environmental compliance and related issues associated with underground construction and tunneling operations, whether new work or rehabilitation. Underground construction and tunneling operations have (in most cases) both an underground and surface component. Since many of the major tunneling projects occur in urban areas, often is areas inhabited for several decades or centuries, environmental problems may already exist in a project area, though that may not yet have been formally recognized. Large projects often attract more than their fair share of regulator attention. This paper addresses the issues with the greatest potential to be encountered by underground constructors, with the emphasis on minimizing contractor liabilities, both in the short- and long-term. Minimizing contractor liability begins with understanding bid documents, contract provisions and necessary means of protection, and carries through project execution by responsible control of hazardous materials, avoidance of media contamination, proper waste disposition, as well as compliance with other environmental requirements.

Jan 1, 1999

By David Martin Menne, Chris Campbell-Hicks

Optimisation of many oxide gold processing facilities, in most cases, either does not really take place or if it does take place it happens too late or takes too long. This is unf01tunate as extra profits and early cash flows are lost, in new projects, and/or may not be realised at all in others. The situation is easily avoid­ed by ensuring that the plant optimisation happens immediately following commissioning or for an established operation simply 'biting the bullet' and making it happen immediately as a 'better late than never' decision. This type of optimisation requires intense undiluted focus on each and every problem or restriction that contributes to reduced plant performance or bottlenecks, without letting go, until the predetermined outcome is produced. Thus a dedicated person with specific quantative goals is required for these tasks. Methodology and strategies for optimi­sation are discussed and numerous examples presented. The secret of successful heap leaching is discussed.

Jan 1, 1998

By D. Harney

Accurate measurement, tracking, and planning are vital for efficient utilization of energy in any mining operation, the major focus of this paper. This can be done with a number of assessments: 1) accurately measure KWH usage and track peak demand periods first; 2) identify the electrical equipment that affects your usage and the conditions that require it to be running; 3) remotely monitor and control as much equipment as possible, especially larger pieces of equipment; 4) with your utility determine that you are on the most suitable rate for your usage profile, then understand how your utility company calculates your electrical bill; 5) recognize how production affects energy usage and utility costs; 6) keep historical records of everything you monitor; 7) make information, live and historical, available to everyone; and finally, with the knowledge of your equipment and energy needs, automate controls that you have identified to optimize your energy usage and time of usage.

Jan 1, 2007

By Tim O’Neil

Many mining companies try to fight their way up from small operator and exploration company to major producer. Not many companies make it. Cambior Inc., formed in 1986, is one company well on its way to making it as a major operating company. In 1993, Cambior surpassed 15.5 t (500,000 oz) of gold production and began operations at its world class Omai gold mine in Guyana. At the same time, the company has embarked on a program of geographic and minerals diversification. Cambior, a Canadian company, now has interests in eight mines, three development projects and more than 100 exploration properties in North and South America. The company’s goal is to derive 70% of its income from gold and 30% from base metals and other minerals. Cambior’s moderate diversification into base metals gives protection against negative gold price fluctuations. It also balances the typically short term gold mines and the longer term base metal mines.

Jan 1, 1994

By W. Kemp Wait

Electronic ore sorting has been in use for over 15 years at many mining operations worldwide. Photometric ore sorting, which operates on the basis of measuring light reflectance levels of a rock surface, is in use at various locations on ores such as limestone, magnesite, gold, talc, spodumene, tungsten and coal. Radiometric sorters have been employed on uranium deposits in the western U.S.A. as well as at certain South African go1 d mines where preconcentrating gold is achieved using uranium association as a detector. A new ore sorter, employing two sensing parameters has been developed. Utilizing both photometric and conductivity sensing modes, this system has application to many gold ore types of North America. The first production machine has been installed at a gold mine near Beardmore, Ontario for the purpose of preconcentrating ore both from waste dumps from past production as well as within the ongoing mining operation.

Jan 1, 1987

By C. H. Rawlins

Deep bed media filtration is used as a tertiary treatment step (after hydrocyclones and flotation cells) to remove fine oil droplets and solids from oilfield water before reinjection disposal or to remove particulate material from surface waters used for waterflood injection. Oil and solids injection requirements are typically <5 ppm concentration at <2 micron diameter. The preferred media for produced water filtration is walnut or pecan shell, however the use of this media has evolved by trial & error and the fundamental mechanisms that occur during separation and media cleaning have not been investigated. A project was initiated to fill in this knowledge gap by analyzing the physical, mechanical, chemical, and hydrodynamic properties of six types of granular filtration media (12/20 mesh size): garnet, silica, anthracite, pecan shell, English walnut shell, and black walnut shell. Comparison of bed packing, oil wetting, attrition resistance, particle strength, and fluidization has led to an understanding of the preferred filtration media for separation of fine oil droplets and solids.

Jan 1, 2010

By R. Hogg, E. Kaya, H. Cho

Investigations were performed on fine grinding of bituminous coal in a laboratory-scale pulverizer. The results indicated that the breakage behavior at relatively coarse sizes (i.e., greater than about 20 µm) is essentially "normal." However, at fine sizes (i.e., less than about 10 m), there is clear evidence of reagglomeration. A simplified population-balance model for simultaneous growth and breakage is formulated. Breakage rates and breakage distributions were assumed to follow the patterns typically observed in simple grinding systems. It is recognized, however, that solid particles and agglomerates may exhibit different breakage behaviors. Agglomeration rates are assumed to be determined by contact probability, i.e., by the relative numbers of interacting particles. Based on comparisons between model simulations and experimental data, it appears that agglomerate rebreakage rates and fragment size distributions are quite different from those for solid particles. The result is that product size passes through a minimum and then increases with time as agglomeration begins to dominate.

Jan 1, 1998