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By Alfred Weiss

At the end of the first decade of digital computing in the minerals industry, geostatistics in North America was still in its infancy. This was in contrast with the rest of the world where the technique of kriging was already widely practiced. By the end of the 1970s, there was increasing awareness among practitioners of its potential. But it was not until the late 1980s that geostatistics was universally applied and accepted. This was due, in large measure, to contributors at Applications of Computers and Operations Research in the Minerals Industry (APCOM) symposia. Such an evolution in new computer methods could again be observed at APCOM 26.

Jan 1, 1996

By Z. Zhang, R. G. Reddy

Viscosities of industrial lead slags with various compositions were measured as a function of temperature using a Brookfield viscometer. Based on the experimental data from this study and other investigations reported in the literature, an expression has been developed to correlate the viscosities of lead silicate slags as functions of composition and temperature. The effect of each individual slag component on the variation of the slag viscosity is identified. The composition dependency of viscosity of lead silicate slags is discussed. The calculated results using this viscosity expression are in good agreement with the measured data.

Jan 1, 2001

By Daniel Tao, Jike Qiao, Hao Ren, Feifei Ji, Gonglun Chen

The floatation of niobite was studied using a number of collectors at various dosages and solution pH’s. Octyl diphosphonic acid was found to be an effective collector for niobite flotation with good selectivity. A flotation recovery of 91.2% was obtained with 140 mg/l octyl diphosphonic acid at pH’s less than 5.0. Infrared absorption spectroscopy (IAS) and X-ray photoelectron spectroscopy (XPS) were used to characterize the interactions of niobite with octyl diphosphonic acid. Species distribution diagram of octyl diphosphonic acid and niobium species was used to elucidate the flotation behavior of the mineral with octyl diphosphonic acid. A chemical adsorption mechanism of niobite with octyl diphosphonic acid was proposed. Keywords: octyl diphosphonic acid, electrokinetic measurements, niobite flotation, XPS.

Jan 1, 2005

By J. A. Botín

NPV is a static measure of project value which does not discriminate between levels of internal and external risk in project valuation. Due to current investment project?s characteristics, a much more complex model is needed: one that includes the value of flexibility and the different risk levels associated with variables subject to uncertainty (price, costs, exchange rates, grade and tonnage of the deposits, cut off grade, among many others). Few of these variables present any correlation or can be treated uniformly. In this context, Real Option Valuation (ROV) arose more than a decade ago, as a mainly theoretical model with the potential for simultaneous calculation of the risk associated with such variables. This paper reviews the literature regarding the application of Real Options Valuation in mining, noting the prior focus on external risks, and presents a case study where ROV is applied to quantify risk associated to mine planning.

Jan 1, 2012

By D. R. Wilburn

This summary of international mineral exploration activities for the year 2013 draws upon information from industry sources, published literature 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 analyses of exploration activities performed by the mineral industry. Three sources of information are reported and analyzed in this annual review of international exploration for the year 2013: 1) budgetary statistics expressed in U.S. nominal dollars provided by SNL Metals & Mining (SNL) of Halifax, NS, Canada (formerly Metals Economics Group (MEG); 2) regional and site-specific exploration activities that took place in 2013 as compiled by the USGS; and 3) regional events that affected exploration activities, including economic, social and political conditions, that were derived from published sources and unpublished discussions with USGS and industry specialists. Commodity and regional compilations are presented in this summary. Because multiple sources are used to develop commodity and regional compilations, reported statistics may vary depending on the source and type of data that are being reported. The SNL data summarize planned company budgets for worldwide exploration activities in 2013 for 20 nonfuel mineral commodities based on surveys returned by companies primarily focused on precious metals (gold, platinum-group metals and silver), base metals (cobalt, copper, lead, molybdenum, nickel, tin and zinc), bulk commodities (coal, iron ore, phosphate and potash), and specialty commodities (diamond, lithium, niobium, rare-earth elements, tantalum and uranium). Information on uranium exploration activities was included in the MEG overview for the first time in 2007. MEG included data on the commodities lithium, niobium, phosphate, potash, rare-earth elements and tantalum for the first time in 2010 because of the increased topical significance of these commodities. Since 1999, companies with exploration budgets of $100,000 and greater were included in the MEG and SNL compilations. SNL budget estimates exclude aluminum, coal, and oil and gas. Budget estimates for iron ore have been compiled since 2011 but reported separately. The post-1999 budget surveys by MEG and SNL cover at least 90 percent of world?s reported nonferrous, nonfuel mineral exploration budgets; the 2013 survey is reported by SNL to cover an estimated 95 percent of these budgets. The 5 percent that is not covered is accounted for by companies that chose not to participate in the SNL survey, private companies that do not publish their budget data, and government-funded exploration activities.

By Steve Wiig

In 1987, the Rock Springs, WY district office of the US Bureau of Land Management (BLM) began to develop an automated system to store, maintain and manipulate more than 14,000 drill hole logs contained in the district's office files for various solid leasable minerals. The development of this system was based predominantly on a trial-and-error basis, with many procedural changes incorporated over time. The current Automated Drill Hole Database and Analysis System will continue to evolve with new software developments and increased personal expertise in this field. The mission of the BLM's Branch of Solid Minerals is mandated by a series of federal laws. The most important are The Mineral Leasing Act, the Federal Land Policy and Management Act, the Federal Coal Lease Amendments Act and the Surface Mining Control and Reclamation Act. Several regulations, promulgated from these laws, dictate that BLM must perform certain tasks and functions as part of its specific duties. The regulations that apply to the BLM Solid Minerals program are codified at 43 Code of Federal Regulations (CFR) 3400 for coal, and at 43 CFR 3500 for non-energy solid leasable minerals, such as sodium, phosphate and potash. Specific functions required of the Branch of Solid Minerals necessitates the use of geologic and drill hole data analyses. These functions can be divided into pre-lease and post-lease. Examples of pre-lease functions that normally require some level of drill hole data analyses include:

Jan 1, 1992

Over 800 mines have closed in Australia in the past 25 years. This paper summarizes the data obtained from those closures and includes all Australian States and Territories and all commodities, including metalliferous, coal and industrial minerals. Twenty five percent of the mines closed due to resource exhaustion or depletion; 24% due to high costs, price drops, or declining grades; 8% due to open pit resource depletion (but with underground reserves remaining) or underground reserves depleted (but plans to open cut remainder) and 7% due to receivership or voluntary administration. The environmental, social and economic impacts of these closures are also significant and include acid mine drainage and impact on mine employees. An understanding of the causes of premature mine closure will better equip mining companies and governments to better manage future mine closures, wherever in the world the mines are operating.

Jan 1, 2007

By V. T. McLemore

The mining industry is at a crossroad. To sustain our technically based society, demands for commodities are increasing, and exploration for these commodities is a must. The debate is between sustainable development and the status quo and begins with exploration, where it is determined if a mineralized area contains enough potential ore to be mined economically. Mineral deposits are relatively rare and depend upon certain natural geologic conditions to form and may not always occur in locations that are most suitable to society. Exploration can be compatible with environmental protection and social responsibility, but difficult challenges face the industry to develop a property that is environmentally, economically, and socially responsible.

Jan 1, 2004

By D. R. Wilburn

his summary of international mineral exploration activities for the year 2011 draws upon available information from industry sources, published literature 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 [ ] analyses of exploration activities performed by the mineral industry. Three sources of information are reported and analyzed in this annual review of international exploration: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia; 2) regional and site-specific exploration activities that took place in 2011 as compiled by the USGS and 3) regional events including economic, social and political conditions that affected exploration activities, which were derived from published sources and unpublished discussions with USGS and industry specialists.

Jan 1, 2012

By J. L. Hoover

The goal of the drill bit consumption study was to develop an equation(s) based on various components that affect bit drill wear and use the equation(s) to estimate the consumption of bits during production drilling. Drill bit data from various geographic locations were compiled and used to develop linear regression equations using the Microsoft Excel Software. Multiple drill bit consumption equations were developed and statistical analysis was used to verify the accuracy of those equations. The equations will allow mining companies to more accurately forecast drill bit consumption when evaluating new mine properties. This capability becomes increasingly beneficial to forecasting as the cost of consumables increases.

Jan 1, 2012

By G. J. Joy

Although rates of pneumoconiosis in coal miners have declined substantially in the United States since the passage of the Federal Coal Mine Health and Safety Act of 1969, new cases continue to occur, including cases of rapidly progressive disease. In contrast, Australia?s underground coal mining industry has reported few new cases of pneumoconiosis for over twenty years. Mortality from Coal Workers? Pneumoconiosis in official health statistics and the prevalence of pneumoconiosis among miners screened in x-ray surveillance programs are also lower in Australia. To understand this disparity, the National Institute for Occupational Safety and Health was requested by both industry and labor stakeholders to examine this issue, with the ultimate aim of reducing the rate of pneumoconiosis among United States coal miners. A number of factors, including coal dust exposure, silica exposure, and coal rank were examined as potential contributors to the above observed differences. Comparison of coal rank data from each country did not show any significant differences. Air sample data from the coal mining industries in both countries show that coal dust levels in Australian mines are somewhat higher than those reported in similar U.S. mines; however, quartz exposure for Australian miners is lower than for many U.S. miners. Assuming that quartz is contributing to the greater number of cases of advanced pneumoconiosis in the U.S., more effective dust control measures, as well an independent exposure standard for respirable quartz in coal mining, need to be implemented to prevent this potentially disabling condition.

Jan 1, 2011

By M. Wiber, P. Nicoll

Rio Algom has embarked on a major programme of expansion with the goal of becoming one of the world’s top-performing base-metal mining and metals distribution companies. To assist the company and its operations in achieving its business objectives, we are implementing an environment, health and safety (EHS) management system, built to be compatible with the 14001 model. We recognize that a sustainable development approach for Rio Algom includes outstanding performance in EHS and community responsibility and is essential to earn acceptance within the communities where we operate or wish to locate; raise capital; obtain permits, and operate efficiently. We are committed to triple bottom line accountability, i.e. full consideration of environmental, social and economic concerns in our business decision making.

Jan 1, 2000

By S. Frimpong

Shovel excavation constitutes a significant component of production costs in any surface mining operation. This makes shovel loading an important cost center that needs to be improved to lower production costs. Optimization of tool design will improve energy efficiency in earthmoving operations. However, modeling the soil-tool interaction is a complex process due to the fact that forces for excavating particulate material are functions of many variables. The magnitude of this resisting force depends not only on the type of soil but on the size, shape and orientation of the cutting element. Moreover, part of this complexity is attributed to the fact that the behavior of the material during excavation is not yet well understood. For the past five decades, researchers have mostly used the passive earth pressure theory to study the soil failure patterns around a cutting tool and to develop force prediction models for design optimization with some success. Although the force models developed from the passive pressure theory have been successful to some extent, they can hardly be extended to a general case because of the underlying assumptions and simplification of tool shapes. This paper aims at reviewing some of the existing empirical and analytical methods of cutting and excavation tool modeling with a focus on their merits and limitations. The paper also explores the use of numerical methods, specifically the discrete element method, for dealing with the unresolved aspects of soil dynamics in excavation.

Jan 1, 2011

By William W. Edgerton, Calvin Locke

INTRODUCTION King County, Washington operates a regions wastewater treatment system that provides treatment to 18 cities and 16 sewer districts in the greater Seattle metropolitan area. The system serves 1.4 million people and currently includes two regional treatment plants. In 1999, a long-range planning study identified the need for a third regional treatment plant, now known as Brightwater. Prior to this project, the county has almost exclusively used the traditional design-bid-build delivery process for its capital projects. However, with the adoption of the RWSP, the county began to study the potential application of innovative project delivery methods. This paper looks at the project delivery methods used for the Brightwater project, based on the specific needs of this large, complex, and multi-faceted project. THE KING COUNTY WASTEWATER TREATMENT SYSTEM In 1958, voters approved the formation of a regional agency called the Municipality of Metropolitan Seattle, or Metro, to build and operate a regional wastewater collection and treatment system. Prior to the formation of Metro, there were no regional wastewater treatment facilities and pollution of Lake Washington and Puget Sound from untreated sewage was a concern for many residents. In 1994, King County merged with Metro. The county’s 1,087 square kilometer (420 square miles) wastewater service area covers most of urban King County and extends into portions of two neighboring counties. The system includes two regional treatment plants, a local plant, 61 pump and regulator stations, and 571 kilometers (355 miles) of conveyance pipeline which convey wastewater from local districts to the treatment plants. As with other areas, the greater Seattle/King County region has seen rapid population growth. The RWSP estimates that the current system would soon reach capacity, and called for the construction of a new third regional treatment plant, called Brightwater, to be operational by 2010.

Jan 1, 2005

By Dick T. Atkinson

Due to improvements in the safety of other aspects of mining (primarily in roof control), haulage related accidents, particularly rail haulage accidents, are about to become the most common category of hazards causing death and injuries to underground coal miners. The major causes of these accidents are collisions between vehicles, men caught between rib and trip or between cars, derailments, and runaway cars. Such hazards can be greatly reduced if the motorman has the capability to selectively couple and uncouple cars from the cab of the locomotive, to transmit braking intelligence to the coupled cars, to determine if the trip is intact, and if brakes are automatically applied in any uncoupled car. These capabilities can be provided through an improved coupler system, designed and built by Foster-Miller Associates under a Bureau of Mines contract. Early in the program, a survey of rail haulage patents and literature was conducted. Manufacturers of couplers, mine cars and braking systems were contacted and information relevant to the remote control mine haulage application was collected. From this information evolved a working specification and a design concept. The key elements of the specification, shown in Table I, are the result of a detailed tradeoff study and considerable thought given to the specific problems encountered in the mining environment. A brief explanation of each element is as follows: Automatic Coupling - The couplers operate similarly with most already in underground use - they latch together when a trip is backed into a car intended for coupling. Remote Uncoupling - From the locomotive, the motorman can decide how many cars are to be uncoupled, operate the appropriate controls, and the desired coupler is opened.

Jan 1, 1977

By R. M. Schuster, F. M. Benavides

Samuel G. Bonasso The article by Benavides and Schuster provides an in-depth study of three transportation alternatives for a four-mine complex in western Kentucky. The examination of aerial tramways was not undertaken as an alternative solution. We feel this is an oversight since industrial ropeways are competitive with both belt conveyance and overland truck hauling. In fact, there are aerial tramway systems, operational today, which are 100 years old and operating with some original components. Maybe unfortunately, there are no fixed rules or guidelines whereby the most cost-effective means of transporting and handling material for a given situation may be selected. Each situation must be evaluated so the variables that influence the selection of the desired alternative can be clearly defined. However, there are in-place industrial ropeway systems that have proven economically feasible over a range of 1.6-50 km (1-31 miles). The more difficult the terrain, the greater the cost efficiency.

Jan 1, 1983

By Daniel Journeaux

Introduction Daniel Journeaux is President of Janod Incorporated. Janod is a family owned and operated company that has been working in the field of slope stabilization since 1970. Daniel has worked in the rock stabilization industry for 25 years and has been President of Janod since 1992. Daniel has been an invited speaker for the Federal Highways Administration for the Northwest and Southwest divisions, Queens University in Kingston Ontario, The University of Laval, Vulcan Materials Company, CSX annual meeting for the Northeast Division. Daniel has written several articles and has been published in Pit and Quarry, World Tunneling, and American Shotcrete Association magazines. What is Required to Remediate Highwalls There are several techniques available to stabilize highwalls or temporary rock walls to allow for safe mining practices. The following are some of the techniques that can economically be used.

Jan 1, 2005

By H. A. Taylor

Graphite is elemental carbon that crystallizes in the hexagonal system as six-sided platelets. It occurs naturally and is mined. And it can be made artificially from petroleum coke in the form of shapes (electrodes) and powders. The market for most kinds of graphite in most end-uses was good in 2004. The 2005 graphite market looks positive. The major graphite prices, as given in Industrial Minerals, remained unchanged throughout the year. The preliminary 2004 U.S. Geological Survey (USGS) prices for natural graphite showed almost no change for crystalline flake. They were $600/t ($544/st) in 2004 and$622/t ($564/st) in 2003. Mexican amorphous graphite was almost unchanged at $150/t ($136/st) in 2004 from$152/t ($138/st) in 2003.

Jan 1, 2005

By S. G. Hardcastle, C. K. Kocsis

Ventilation is an expensive prerequisite for underground mining. Current mining trends, including increasing depth and mechanization and more stringent health regulations would generally dictate that more air volume is required in order to provide good working conditions underground. However, any increase in the mine’s intake airflow can produce a disproportionate increase in power consumption and hence operating costs due to the cubic relationship between the sup-plied air power and the airflow (Power a Flow3). Furthermore, forecasts of significant increase in energy prices and new commitments with regard to reductions of greenhouse gas(GHG) emissions, determined the mining industry to look into developing new concepts, design tools and incorporate the latest mining technologies in order to lower capital and operating costs while meeting commitments regarding GHG emissions. The advances in computing power and modelling software now make it possible to design, model and schedule a mine from opening to closure. A developing trend is to design and plan the mine by means of orebody modelling software, followed by using discrete-event simulation techniques to predict production rates and evaluate various operating scenarios throughout the life of the mine. The authors are currently evaluating how such process simulators could be adapted in order to forecast the need for materials or a specific resource, and one of these would be the mine’s “life-cycle” airflow demand as a function of scheduled production rates and mine operating characteristics. Further to this, based upon the mine’s life-cycle airflow demand schedule, the ventilation system could then be designed using a mine ventilation simulator. This new design approach would integrate in parallel the development of the ventilation system with the current mining conditions, therefore, heading towards “develop-as-you-go” as opposed to developing the system for final requirements with high upfront costs. This new ventilation system design criteria would also incorporate the use of the “ventilation-on-demand” technology, which will further lower development and production costs and implicitly, the mines’ GHG emissions.

Jan 1, 2004

By Andrew Finney

INTRODUCTION The Sacramento Regional County Sanitation District (SRCSD) serves unincorporated areas of Sacramento County, parts of the cities of Sacramento and Folsom, and the cities of Citrus Heights, West Sacramento, Rancho Cordova, and Elk Grove. SRCSD maintains 145 kilometers (km) (90 miles) of interceptors that convey a combined total of 0.6 million meters3 per day (160 million gallons per day) or more of waste-water, with additional miles of sewer interceptors that are scheduled to be built by 2020. Wastewater is conveyed to the Sacramento Regional Wastewater Treatment Plant in the southwestern portion of the County, also managed and operated by SRCSD, in interceptors with diameters as large as 3.0 m (120 inches.) As part of its overall expansion program, SRCSD has constructed a number of major interceptors over the last few years with tunneling methods due to concerns associated with either the impacts of open cut construction in an urban environment (traffic, safety, noise, environmental concerns) or the need to achieve a crossing of a stream, river, or transportation corridor. This paper focuses on a specific issue that affected construction of the Upper Northwest Interceptor (UNWI) Sections 3&4 project, located at the northern limit of the SRCSD service boundary and within the limits of the City of Sacramento. This project involved the construction of 3.2 km (2 miles) of 2.1-meter (84-inch) and 2.4 km (1.5 miles) of 1.7-meter (66-inch) diameter reinforced concrete pipe (RCP) using MTBM, EPBM, and 3.3-meter (130-inch) two-pass TBM methods. The owner elected to install the RCP using tunneling for a number of reasons including a desire to avoid traffic impacts in a dense urban corridor, to minimize disturbance to the neighborhood, and to avoid potential dewatering-induced settlement issues along the western one-third of the project. For the western portion of the alignment the 2.1-meter (84-inch) reinforced concrete interceptor pipe was to be installed using a 2.7-meter (105-inch) earth pressure balance machine (EPBM). No external dewatering of shafts or tunnels was permitted for reasons of concern about settlement, discussed previously. At the intersection of Elkhorn Boulevard and Natomas Boulevard (at the extreme northwest corner of the project) the 2.7-meter (105-inch) EPBM tunneled past a recently constructed 11-million liter (3-million gallon) water storage reservoir, passing within 3 meters (10 feet) of the tank?s shallow foundation while tunneling through clean sands with a shallow groundwater table. The paper will discuss the implemented solution to mitigate additional settlement risk that was developed as a joint collaboration between the owner, CM, designer, and contractor.