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By J. R. Mattern

The engineering geology of the Rio Tinto Borax Boron Mine creates challenges in providing practical slope design recommendations to mine planning engineers. Low strength sedimentary units interbedded with very low strength lakebed clays surround the orebody. Faulting has offset and juxtaposed these units into variably adverse orientations, while groundwater is compartmentalized both vertically and horizontally within fault blocks. A collective program of geologic data collection, geomechanical strength testing, geologic modeling, slope depressurization, confirmation of underground stope locations, and documentation of slope behavior provides vital information for design investigations and sensitivities. Analysis results lead to risk assessments and operational procedures that add value to the business by optimizing slope configurations and minimizing risk.

Jan 1, 2004

By E. D. Dainty, B. E. Enga, D. L. McKinnon

Following considerable laboratory studies concerning particulate control systems for underground use, a program was commenced to develop practical real life implementation systems. This program covers the implementation in seven mines of particulate filter systems to 10 engine models from three engine manufacturers in 12 different vehicle types, a total of 24 vehicles. As the program ran, one mine had to drop out and a mutually agreed upon system could not be arrived at for another. Hence, the program included five Canadian mining companies. Several of the vehicles trialed at Brunswick Mining were trialed by Brunswick themselves. Nonetheless, the data is presented. This paper covers the work performed from the beginning to the end of the demonstration program. Data collected to properly select and design filter systems along with technical conclusions of the demonstration are presented. Also presented are the results of a survey that highlights the participating mines' acceptance of the technology.

Jan 1, 1991

By Bernard J. Reddy

This paper describes in detail the economic forces affecting cobalt supply, demand, and prices. The major factors that will determine the growth or decline in the use of cobalt in each of its applications are discussed. The flows of cobalt from mine to refinery are described on a company-by-company basis. The paper concludes with a discussion of how the characteristics of the supply and demand sides of market interact to determine cobalt prices.

Jan 1, 1986

By A. Vargiu, R. Ciccu, G. Massacci

Based on the current results of field practice and on experimental data obtained in the laboratory with a suitable testing apparatus, the industrial operation of diamond wire cutting can be simulated by means of a mathematical model capable of predicting the cutting velocity and the wear rate of the tool, and thence the cost figures, achievable for a variety of conditions (kind of rock, size and shape of the cut, position of the equipment) according to a predetermined setting strategy (peripheral velocity, pull- back force). The paper gives a short outline of the model and discusses the simulation results obtained in a number of cases aiming at singling out the most favourable conditions for a cost-effective use of diamond wire.

Jan 1, 1996

By S. P. Liebenberg

During the past fifteen years significant progress has been made on carbon-in-pulp (CIP) technology for the extraction of gold. While most research on the mechanisms and kinetics of CIP sub-processes has focused on the adsorption step only, auxiliary unit operations such as elution have received less attention. The mathematical models which have been developed for elution at the University of Stellenbosch can be used for design as well as process optimisation by incorporation into an overall CIP simulation program. Except for these models, no other comprehensive models for the complex elution process are available. It is the aim of this paper to review recent modelling work on competitive elution from activated carbon.

Jan 1, 1995

Almost all of the world?s zirconium is mined in the form of zircon (ZrSiO4), the majority as a coproduct of titanium mining from heavy mineral sands deposits. These are placer type deposits, in which the dominant mineral is silica but which also contain a suite of ?valuable minerals,? often consisting of a mixture of titanium minerals, various alumino-silicates and zircon plus a range of other mineral species. The composition of the valuable minerals in such deposits is known as the mineral assemblage. There is no reasonable consistent geological relationship between zircon and titanium minerals. They can derive from separate igneous rock deposits that rarely occur together. The connection emanates once these separate rocks have been eroded by weather and water, often across a very long geological period. Once this has happened, zircon and titanium minerals often find their way to the same locations because they share two major characteristics:

Jan 1, 2011

By Dirk van Zyl

Three conditions are required for a risk to be realized: (1) a source of risk (i.e., hazard) must exists (2) some process must take place which will lead to the exposure of people, animals, and/or the environment to the hazard: and (3) as a result of the expense, undesirable effects are produced on the people, animals, and/or the environment. A comprehensive risk assessment addresses all three of the conditions through the following four steps: (1) risk source (hazard) characterization, (2) exposure assessment, (3) dose-response assessment, and (4) risk estimation. Although the terminology may differ, the overall approach of financial, public health, and environmental risk assessments is the same (National Science Foundation, 1985).

Jan 1, 1988

By Allison L. Hornbaker

Millions of years ago, in late Cretaceous time before man existed on Earth, tremendous orogenic forces began to change the face of the western part of the North American Continent. Catastrophic events marked by huge uplifts of thousands of square miles in the Cordilleran Belt, some of which are barely discernible in the geologic record, were accompanied by long periods of batholithic intrusions and volcanic eruptions. These events produced the great Rocky Mountain systems, which were at the time even higher and more rugged than they are today. Such activity continued into Tertiary time, and during the Pliocene and Pleistocene periods millions of tons of volcanic ash were hurled skyward by explosive volcanic activity and carried by the westerly winds to the east where it settled out of the atmosphere and deposited over thousands of square miles of the high plains. Unusually heavy rains, probably caused in part by the volcanic activity itself, together with high winds, reworked and redeposited the freshly fallen ash into lakes and depressions of varying sizes and shapes. Subsequent deposits of sand, gravel and loess covered the deposits of volcanic ash, preserving them in the condition in which they are found today. In many places erosion has cut through the sand, gravel, loess, and volcanic ash so that in favorable localities on hillsides and gullies, exposures of volcanic ash can be seen interbedded with sand and gravel.

Jan 1, 1970

By William Gleason

"More than 6,300 people converged on the Colorado Convention Center for the 2017 SME Annual Conference and Expo and 119th National Western Mining Conference in Denver, CO on Feb. 19-22. Many of them crammed in to hear Douglas Silver deliver the keynote address to the conference.Silver is a portfolio manager for Orion Mine Finance, a private-equity fund focused on providing funding to advanced-stage base and precious metal projects and is one of the most respected voices in the field of mineral economics. Prior to joining Orion, he served as chief executive officer and chairman of International Royalty Corp., a global mineral royalty company, which he founded in 2003 and sold in 2011.Those who were hoping that Silver would deliver at least a bit of optimism during his 90-minute presentation got what they came for from the talk titled, “When are commodity prices going to rebound?”It marked the second time Silver has presented the keynote address to SME, the first was in 2008 and was delivered during the height of mining’s super cycle (ME, June 2008). In his 2017 address, Silver looked back on the previous 10 years and the massive contraction of the global economy that resulted from the great recession that began near the end of 2008.It has been a challenging time for the mining industry. About US$1.4 trillion was lost in the global mining stocks from 2011 to Jan. 6, 2016. Major mining companies exceeded $60 billion in write downs between 2012 and 2013 and investors lost confidence in the sector, putting the global mining industry into a bear market that has taken mining equities to historic lows.However, that was then and this is now.Using numerous examples, including rising commodity prices, a steady decline in the U.S. unemployment rate, increases in discretionary income and the Dow Jones Industrial Average, which topped the 20,000 mark for the first time ever in February, Silver theorized the current down cycle is near its end and the demand for metals and other commodities will see a sharp increase by 2025. He also noted that investors are beginning to rotate back into mining equities."

Apr 1, 2017

By K. A. Natarajan, M. K. Yelloji Rao, P. Somasundaran

The bacterium Thiobacillus ferrooxidans triggers the surface modification of sulfide minerals to provide hydrophilicity or hydrophobicity for the flotation of sphalerite and galena. The effects of initial cell concentration, period of biotreatment and pulp density on the floatability of the minerals are discussed. With galena, flotation enhancement obtained through sulfuric acid treatment was retarded by biotreatment at all cell concentrations due to chemical effects. Such a decrease occurred for sphalerite only at cell concentrations sufficiently high for bacterial attachment to the mineral surface. The variables affecting surface modification (and, thus, flotation response of the minerals) include the cell concentration used for bacterial conditioning, the period of biotreatment and the pulp density. Although bacterial growth during biotreatment was observed even in the absence of nutrients, such growth was more common in the sphalerite suspension than in the galena suspension. Cell protein estimations suggest that more cells are attached on galena than on sphalerite. Probable reaction mechanisms associated with bacterial modification are discussed.

Jan 1, 1993

By Fred A. Glover

It's a pleasure to be included with this group. I am not here to sell my services, but rather to share with you some ideas and considerations on using environmental consultants. Environmental consultants have developed some problems as well as created new costs for companies that are as legitimate as engineering costs. Each day the mining industry is becoming more affected by the proliferation of environmental regulations and their interpretations by federal and state agencies. How does a modern mining company cope with all the demands for environmental consideration by regulatory agencies and special interest environmental groups-- yet produce a product and make a profit? One way is to make efficient use of environmental consultants. But, as everyone here knows, this approach has been fraught with seemingly inherent frustrations, difficulties, and much justified criticism.

Jan 1, 1979

By C. Haycocks

In spite of the increasingly high capital investment required for longwall mining equipment, there continues to be a steady trend towards this form of mining. This move is caused in large part by improved productivity of longwall mining systems combined with greater percentage of coal recovered over room and pillar mining, reduced manpower requirements, and the inherent safety of the system. Longwall mining is most amenable to the greater depths experienced by many mining operations, particularly in the coalfields of the Eastern United States. Two primary problems in the installation of a longwall panel are determining whether a particular seam is suitable for longwall and, secondly, type and capacity of equipment required for such a mining operation. In addition, recent legislation has forced an evaluation of the surface effects of longwall mining with a view to determining what, if any, surface damage might result from extracting any particular panel. These factors must be determined using large and often complex quantities of geological, structural, mining, and surface data. This makes the problem most attractive to solution using the computer.

Jan 1, 1979

By A. G. Naguib

In essence, any magnetic separator operates on the basis of imparting a preferential magnetic force on particles of higher magnetic susceptibility which are to be separated from particles of lower magnetic susceptibility. A certain amount of directional deviation to the particles takes place thus allowing for collecting each category of particles separately. The forces in action on particles in a wet magnetic separator of the established designs can be analyzed in a simple manner as shown in Figure 1.

Jan 1, 1972

The implementation of NAFTA in January 1994 was expected to have small but beneficial effects on the Mexican economy, mostly through increased investments. Mexico's mining industry was especially likely to benefit, as mineral investment funds would be diverted to the now safer Mexico and away from similarly endowed but more risky Latin American mineral economies. The results during the past two years have shown that it is government and macroeconomic factors that influence investment flows, rather than the fine tuning of trade flows through so called “free-trade" agreements.

Jan 1, 1998

Traditional finance theory recommends discounted cash flow (DCF) analysis as the tool to value mineral properties. Yet, the calculated values by this method are usually lower than the market value. Finance theory also advises us to develop an undeveloped project immediately if its net present value is positive. Most projects are, however, only developed when the economics are highly favorable. This paper uses insights from option-pricing theory to explain these divergences between market behavior and finance theory and presents simple modifications to discounted cash flow analyses that will lead them to produce correct valuation and development timing advice.

Jan 1, 1999

By Lennart Malmqvist

Decision-making in exploration deals with experience, knowledge, and sometimes faith, but very often financing and profit, mineral resource aspects, employment, and general political ambitions are parts of the scene. At one end of this spectrum, there is the prospector and his decision on the actual project. The exploration business now expands from its pioneering phase for the benefit of a single company to a wider spectrum which includes the benefit of the large mining consortium and a national development program. Its objectives are also to maintain employment and to favor long-term stability in a mining district or a mining company. The prospector then has new aspects and questions to consider such as, what to do in mining districts where there is a shortage of ore resources but there are still useful investments in mines, processing plants, etc. To analyze the exploration process, therefore, seems to be of great importance in a time of rapidly changing conditions. As in other areas of complex decision-making, for example, in the fields of investments, of production, and of the armed forces, computers most certainly have an important role to play in future exploration decision-making systems. However, we must first analyze our own business as closely as possible to find out what kind of information we need, i.e., why we recommend an exploration program as a good or a poor one. An important part of the debate about exploration is the case study. Case studies on exploration are few and most of those written are only about successful exploration programs. Where are the case studies of the failures and the not so successful programs? Every prospector knows that the majority of exploration projects fail. Consequently, the most important experience seems to be hidden in the failures.

Jan 1, 1979

By Y. M. Jiang

Longwall faces can move at high advancing rates, but many geological variations can cause unexpected instabilities and production losses. The rapid movement makes it necessary to evaluate different geologic conditions in the rock mass as fast as possible to assess their effects on the longwall face and shields. It is believed that prompt awareness of geologic conditions is the key to preventing instability at a longwall face. This paper introduces the application of fuzzy set theory for characterizing and evaluating roof conditions. Real-time monitored data coupled with fuzzy set analysis provides valuable information, such as shield leg pressure, developing load on shields, intervals of periodic weighting and the ratio of developing loads during periodic to normal times.

Jan 1, 1997

By J. A. Finch, J. Yiantatos, A. R. Laplante

This paper re-examines the mixing conditions in the collection zone of flotation columns. These have in the past been characterized with a single uniaxial dispersion coefficient, E. The relationship between E and column diameter, Dc, is examined based on residence time distributions (RTDs) in columns of Dc ranging from 5.lcm to 184cm. Results agree with published correlations in chemical engineering, i.e. E a Dc '" , Data explain why pilot columns display significant upgrading between the feed level and the interface, whereas plant columns do not. It also suggests that, for plant columns, the full collection zone (up to the interface) can be considered when calculating the residence time. A mathematical model considering two regions of different mixing was compared to the single E model. Both models adequately fitted measured age distributions inside the column and overall RTDs. Measured and simulated mixing characteristics are compared to those of flotation banks, using a tanks-in-series approach; banks of comparable mixing to columns are identified.

Jan 1, 1988

By G. G. O. O. Uwadiale, E. G. Okafor

A study was performed to characterize the Ishiagu lead-zinc deposit prior to beneficiation. The study included the use of XRD, SEM and both reflected- and transmitted-light microscopy. The results showed that the ore consists mainly of galena (PbS), sphalerite (ZnS) and quartz (chert), with pyrite, siderite and chalcopyrite occurring as trace minerals. The textural relationships among the minerals, their grain sizes and their locking characteristics, coupled with the chemical analysis of the ore, indicated that the galena and sphalerite can be separated by conventional beneficiation methods.

Jan 1, 1998

By R. L. Grayson, S. Yuan

A goal-programming-based, worker-scheduling model has been incorporated in the Mine Management Support System (MMSS) for assigning workers to prioritized jobs on a shift basis. In the model, the accomplishment of each regular and non-regular job is a goal, and the objective is minimization of the deviations from the goals. A number of coefficients are employed as premultipliers of the decision variables to address practical considerations associated with the utilization of workers and the requirements of jobs. This model is applied to a 41-worker problem.

Jan 1, 1992