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By Timothy J. Haddon

For the mining industry in general and gold mining in particular, the past few years have been difficult. Economic conditions, coupled with growing regulatory restrictions, have led to increasingly important reasons for managing assets wisely. From a public company perspective, such asset management makes sense because it ultimately provides for an increase in shareholder wealth, and that is why we are in business. Regardless of whether a company is public or not, assets must be managed effectively to remain a player in today's competitive environment. So, as the chief executive officer of a gold mining company, how do we manage our assets to ensure that we are satisfying our obligations to our customer-the Amax Gold shareholder? The gold industry has been under siege. We have just completed the third year with average prices below $12.85/ g ($400/oz). When finding, and/or acquisition costs and development costs to operating costs are added, there isn't much of a profit margin left. What this environment provides, however, is opportunities for growth. In the gold business, you either grow or you die. Today, most North American gold producers have, at most, a 10-year mine life. We are all scrambling to add reserves so we do not become extinct. As prices remain low, opportunities abound for increasing diminishing reserves. This is the time for the opportunistic company to take advantage of market conditions and that is precisely what Amax Gold has done. There are six components to running a successful gold business: • finding reserves through exploration, acquisition or joint venture, • financing the project, • permitting and constructing the project, • operating the project, • cash management and • communication.

Jan 1, 1992

By VASU GANGRADE, Marcia Harris, Kumar Vaibhav Raj, Jim Addis, Khaled Mohamed, Snigdha Sarkar

The National Institute for Occupational Safety and Health (NIOSH) conducted a ventilation assessment for a recently established underground room-and-pillar stone mine implementing split-mine ventilation. The primary objective was to examine the impact of the length of the in-place stone stoppings on face ventilation efficiency. These stone stoppings serve to separate the intake and exhaust entries and align with the mining direction. To achieve this, computational fluid dynamics (CFD) modeling was utilized. The appropriate turbulence model was selected, and a mesh convergence analysis was conducted for the CFD model. Following that, the CFD model was validated using the conducted ventilation surveys. Two configurations of in-place stone stoppings, designated as Layout-I and Layout-II, were simulated using the validated CFD models. Layout-I featured a shorter in-place stone stopping, while Layout-II had a longer one. The results obtained from the CFD models demonstrated that the increased length of the in-place stone stopping in Layout-II resulted in a notable enhancement in ventilation efficiency at the advanced faces (last stopping), elevating it from 4% in Layout-I to 8.4% in Layout-II. However, no significant impact of the in-place stopping layouts was observed at other faces. In general, Layout-II exhibited a greater circulation of air at the outby stoppings.

Feb 1, 2024

By Tristan Joubert, Fabio Panella, LiLing Chen, Yung Loo, Michael Devriendt, Nasir Qureshi, Ahmad Ali

Tunnel inspections have traditionally been carried out manually by inspectors writing up observations and taking photos of defects. The results from the inspection and the defects observed are dependent upon the rigor of the inspectors and may be subject to repeatability and consistency issues and is often time consuming with elevated health and safety risks. This paper will discuss work that is being carried out in developing and implementing an innovative hardware and software solution integrating machine learning to automate the process of capturing objective tunnel condition information, offering cost and programme savings as well as health and safety improvements

Jun 13, 2023

By John S. Summer

The induced polarization (IP) method of geophysical exploration is capable of detecting even small amounts of metallic luster minerals in a rock mass. Consequently, in the years since discovery, IP surveying has become the most popular ground geophysical survey method. It is not too difficult to understand many applications of IP surveying as used in the search for mineral deposits. However, the basic theory of the IP phenomenon is not well developed or understood, and there has been some disagreement on fundamental concepts. In order to most effectively apply the IP method in the field it is necessary to know the physical characteristics of the sought-for deposit including its size, shape, depth, and electrical properties. With this information an optimum IP search arrangement can be devised and one could use the best possible electrode interval, type of array, and line spacing. With uncertain target characteristics as encountered in the real world, geological guidance must be used to help direct an optimized IP survey.

Jan 1, 1972

By P. Somasundaran, D. R. Nagaraj, Tarun Bhambani, P. Patra

Flotation separation and recovery of value minerals from ores containing fibrous silicate minerals are known to be quite challenging. Earlier studies have established that the metallurgical challenges (poor selectivity and recovery, high energy consumption, etc.) arise from the impact of the fibrous minerals (with high aspect ratio) on pulp rheology, which was found be rather complex. The complex rheological behavior of ore suspensions containing particles with high aspect ratio and its influence on flotation outcome are investigated in this study. Flotation tests and rheological measurements were carried out with both ores (containing fibrous minerals) and a model system comprising nylon fibers (chemically inert) added to a copper ore that had no fibrous mineral. These studies allowed the determination of contributions of physical properties of the fiber to pulp rheological behavior. Optical microscopy images of the fiber pulp indicated that the fibers entangled to form two levels of microstructures: two-dimensional (2D) aggregates under semi-dilute (< 20% solids) conditions and three-dimensional (3D) microstructures at concentrations > 30% solids. The yield stress (σ) values determined for the fiber pulp were logarithmically related to the volume fraction of the 2D/3D structures. The relationships developed here for different ARs showed that the yield stress of a flotation pulp changes with respect to shape, size, and the concentrations of the microstructures. Implications to the effects of such entangle networks on selectivity of flotation separation are discussed.

By Nikhil Dhawan, SHAILA MIR

The emerging problem of electronic waste has promoted the interest in exploring metal recovery from secondary sources under the umbrella of urban mining. This study presents the physical and chemical characterization of various components present in end-of-life laptops to help ascertain the sites of metallic values and develop sustainable and environment-friendly recycling. The recycling potential of a laptop is evaluated by sequential disassembly, separation, and characterization of components such as body (49.8 wt.%), printed circuit board (9.7 wt.%), hard disk drive (4.9 wt.%), and battery (12.4 wt.%). The printed circuit boards comprise metallic values, majorly copper (25 wt.%), tin (5.8 wt.%), and lead (3.1 wt.%). The precious metals (Au, Ag) with an economic advantage are abundantly present in electronic components such as integrated circuits, capacitors, resistors, and processors. Critical elements such as lithium, cobalt, and rare earth elements are detected in the discarded laptops' batteries and hard disk drives. The recycling potential representing the amount of material that can be recycled in various components, depending on the type, concentration, and purity, is determined in the range of 36–100%. On average, a unit laptop contains~ 386 g of Cu (14.45 wt. %), 49.73 g Co (1.86 wt. %), ~346 mg Ag, ~141.2 mg Au, ~650 mg of rare earth elements (Nd, Dy). This study presents a database for investigating integrated and economical recycling techniques from different components of a laptop, and an overall process flow is also proposed.

Jul 24, 2021

By John W. Stevenson

At the No. 4 Mine of Jim Walter Resources in Tuscaloosa County in the North Central part of the State of Alabama, the Mary Lee and Blue Creek coal beds lay 2000 feet below the surface. The quantity of methane gas stored within the coal bed reservoir at this depth and released during development mining necessitates that each coal producing section be ventilated using large air quantities approaching 100,000 cfm. In order to meet coal contractural commitments in the early stages of mine development by installing the necessary number of continuous mining machine units and to develop the mine to projected air shaft sites, high pressure, large volume mine ventilating fans were required. This presentation discusses the installation start-up and changeover procedures when two size GAF 31.5-28-1 TLT-Babcock 3500 Horsepower fans with adjustable pitch in flight blades were put on line while phasing out two Jeffrey Mining Machine Company 8HUA 117 Fans. A graph will be presented to depict the most economic diameter shaft size under 2000 feet of cover with different air quantity requirements.

Jan 1, 1982

By W. J. D. Stone

Many of the common valuable minerals have a magnetic susceptibility which is sufficiently high to render them amenable to magnetic separation. In addition,, many minerals which form the unwanted constituents of an ore can be removed by magnetic means. Magnetic separation in general has suffered seriously from, the lack of a high intensity wet separator. It is only recently that such a separator has become available to the industry. Prior to this, high intensity magnetic separation has been limited to the use of the dry techniques. Since the introduction of the Jones Wet High Intensity Magnetic Separator, extensive test work has been conducted to investigate possible applications. From the investigations conducted and the discussions that have taken place in the industry, it is apparent that the important mineral characteristic of magnetic susceptibility is not receiving the attention that it deserves. Applications for high intensity wet separation are being found in areas hitherto not considered.

Jan 1, 1963

By P. W. Conrad, C. Todd, N. A. Degerstrom, N. West, R. Kramer

"Surface subsidence caused by underground room-and-pillar mining operations and by solution mining operations have been studied separately but never in combination. In 2008, FMC Minerals began using solution mining at its Westvaco Mine as a secondary extraction method in an area that had been previously mined using the room-and-pillar mining method. Mining regulations require that subsidence associated with underground mining activities be monitored and measured annually. Using Salt_Subsid, a subsidence software package from the Solution Mining Research Institute, and ArcGIS, Esri's mapping platform, researchers at Montana Tech were able to develop a relationship between measured surface mine subsidence and solution mining that can be used at the Westvaco Mine to estimate the production of trona from solution mining operations. Project backgroundFMC Minerals has increased the production of trona from its Westvaco Mine near Green River, WY, using solution mining as a secondary extraction method in an area previously mined using the room-and-pillar method. The area of interest was mined until 2001 with the use of a borer miner at a depth of approximately 488 m (1,600 ft). Currently, FMC determines the amount of trona produced using its solution mining operations by measuring the dissolved solids pumped from the mine. This approach, however, does not account for the location from which the trona was removed.The location from which the trona is removed and the size of the cavern created by the solution mining operations are important to FMC’s mine planning. FMC believed that with proper investigation of the subsidence at the Westvaco test site, a correlation might be found between surface subsidence measurements and the amount and location of trona production from the solution mining activities. The primary goal of this project, conducted by Montana Tech, was to find relationships between the measured subsidence and the solution mining activities. The project attempted to develop an equation that could be used to predict solution trona production based on measured subsidence. The project attempted to model the relationship between the measured surface subsidence and solution mining production using Salt_Subsid, an existing subsidence software package from the Solution Mining Research Institute (SMRI, Clarks Summit, PA) to estimate the location, size and shape of the solution mining cavern. This study would determine the program’s usefulness for locating and developing the cavern created by secondary solution mining activities. The subsidence and production data sets used in this study were collected over a seven-year period from 2008 through 2014."

Jan 4, 2018

By T. R. Ellis

"In August 2013, the Appraisal Practices Board of the U.S. Appraisal Foundation issued its “APB Valuation Advisory #4 - Identifying Comparable Properties,” which contains analysis and examples that may suggest a broader meaning of the term “comparable properties” than is current convention in real property value appraisal in the United States and internationally. The advisory is directed at the appraisal of real property of all kinds, including interests in mineral properties, as indicated by the inclusion of two mineral property appraisal papers in the appendix that lists suggestions for further reading.This paper firstly reviews as background the historical meaning of a comparable property, with its perceived constraints, against real-world examples of transacted mineral properties that are adjusted to subject properties to provide market value indications. The advisory’s findings are then examined and evaluated as to whether they may influence and benefit the work of mineral property appraisers, particularly in situations where their sales comparison analyses may be challenged. The conclusion is that the combination of constraints that the advisory’s findings specify for use of the term “comparable” will for mineral properties be met infrequently or rarely. As a result, mineral property appraisers are advised to avoid using the terms comparable or “comp” when referring to transactions of mineral properties that they analyze to derive data for appraising the value of their subject mineral properties. IntroductionA mineral property appraiser rarely finds a sale of a mineral property that meets the literal meaning of the term “comparable sale,” by being directly comparable to the subject property of the appraisal in all factors of significance in the determination of the value of the property interest being appraised. Real estate appraisers have long used a more liberal interpretation of the meaning of comparable sale and its commonly used abbreviation, “comp.” Real estate appraisers compare sales to their subject property on the basis of price per hectare or acre of land and price per square meter or square foot of building floor area. Adjustments totaling to within the range of +30 to -30 percent from the sale property to the subject, before factoring in the property area, have generally been viewed as appropriate for the sale to be considered a comparable sale."

May 1, 2016

By Eugene A. Hickok

Seismic surveys utilizing the MD-1 have been performed by Geophysical Specialties Company since 1957 in many parts of the, U. S. and Canada and in several foreign countries. These surveys have proven the refraction seismic technique to be applicable to a wide variety of engineering problems. The best known applications of the instrument have been in the, construction industry, where it is used for the delineation of material and mineral deposits and for bedrock depth determinations. Fast on-the-site depth determinations give reliable subsurface&apos; information even in boulder-strewn soils. A widely publicized use of the MD-1 is to make rippability studies in which the instrument is used to determine the seismic velocity of the materials to be excavated. By use of special tables which correlate rippability with seismic velocities, such as those prepared by the Caterpillar Tractor Company using the MD-1, the rippability of-a specific material may be determined.

Jan 1, 1962

By Bronson Stringham

The close area! relationship of Cretaceous or later intrusive porphyries to larger hydrothermal deposits of Pb, Zn, Au, fig, Cu, Mo, Hg,, and U of similar age in the Basin Range Province, was statistically shown in a recent paper (Stringham1) During the past year this study has been expanded to cover p11 of the larger hydrothermal deposits of similar nature occurring in the entire western United States. The sandstone type uranium deposits of the Colorado Plateau and Wyoming have been excluded since considerable controversy exists regarding their origin. The close relationship between intrusives in general and hydrothermal ore deposits has long been-recognized, but the association involving intrusive porphyry only, was suggested in 1954 when Sales concluded that the formation of porphyry may be an intermediate stage of activity between the development of granitoid rock and certain types of copper deposits. However: he applied this concept to only a few copper deposits. The relationship appears to be true also for a great majority of the hydrothermal deposits of the other metals mentioned above of Cretaceous and later age, at least in the western United States. This situation then leads to the conclusion then when exploring for similar types of hydrothermal deposits of the metals considered one may feel reasonably sure that if an intrusive porphyry of considerable size is. not present he may be facing much greater risk of finding an ore body than if a prophyry were presents Since, there are many intrusive porphyritic rocks which do not seem to be associated with hydrothermal deposit, it is believed that some distinct value can come from the recognition of intrusive porphyry which might be barren as well as the intrusive prophyry which might be productive This paper deals with that problem.

Jan 1, 1960

By G. Ferrara, P. Bozzato, B. Chinè

To obtain a reliable comparison between conical and cylindrical separatory vessels used in dynamic dense-medium separation systems, the following two studies were made: a study of the swirling flow in conical and cylindrical vessels using laser-Doppler velocimetry (LDV) and a study of the behavior of suspensions of magnetite and ferrosilicon in water in both separators. It was found that the tangential velocity profiles differ in conical and cylindrical vessels. In a conical cyclone, free vortex conditions affect the largest part of the vessel, while in a cylindrical vessel, the motion approaches that of a forced vortex, i.e., that of a centrifuge. It was also found that the conical vessel manifests higher centrifigal acceleration and very strong densifying (the density differential) and, hence, the density gradient inside the vessel is large. It was found that the cylindrical vessel manifests lower centrifugal acceleration and low densifying, i.e., low-density differentials, and hence, the density gradient inside the vessel is small. Also, due to greater densifying, the density cut-point in cyclones is higher than the operating medium density, while, in cylindrical vessels, the density cut- point is closer to the medium density. The results provide an interesting description of the differing behaviors of conical and cylindrical vessels, and they help explain the differences in pegormance between the two types of separators.

Jan 1, 2000

By J. H. Kim

Since the Hardy Cross numerical algorithm was applied to the solution of mine ventilation networks, there have been numerous developments in ventilation network analysis procedures. The Newton-Raphson method, the linear theory method, and the second-order approximation method are three of the additional approaches that have been applied. The efficiency of a ventilation network analysis procedure depends not only on the method of solving the system of equations derived from ventilation networks, but also on the method of deriving the equations through selection of the meshes. This paper investigates the impacts of three mesh selection methods on the efficiencies of four ventilation network procedures. The minimum-resistance spanning tree method is the most popular procedure for selecting meshes. The shortest-path method was suggested by Epp and Fowler (1970) for improvement of the Newton-Raphson method. The minimum-resistance-path method is suggested here as the third method of selecting meshes. The effects of these three methods on the Hardy Cross method, the Newton-Raphson method, the linear theory method, and the second-order approximation method are analyzed in this paper. These network analysis methods have been summarized in the paper by Kim and Mutmansky (1991).

Jan 1, 1992

By T. J. De Mull

The Alligator Ridge Mine is located 70 miles northwest of Ely in White Pine County, Nevada. Development of the mine began in the late 1970&apos;s as a joint venture between Amselco Minerals, Inc. and Occidental Minerals Corporation, with Amselco as the operating partner. Early in 1983 Nerco Minerals Company acquired Occidental&apos;s share of the property. The mine and ore processing facility have operated at capacity since 1981 producing 680,000 tonnes of ore and 1,900 kg of gold per year. The gold ore deposits at Alligator Ridge consist of disseminated micron-size gold particles in a silicified siltstone matrix. The deposit comprises three separate but adjacent areas of mineralization that are designated as Vantage 1, Vantage 2, and Vantage 3 after the name of the basin in which the deposits lie.

Jan 1, 1983

By Karoly (Charles) Kocsis, August Greth, Jon Fox

"It is the duty of the mine operator to ensure the mine environment is healthy and safe for the mine workers. For deep and hot underground mines, this requires maintaining adequate working temperatures by means of mitigating the heat load generated by strata, auto-compression, mining equipment, explosives, ground water and human metabolism. The heat load is best reduced by minimizing the amount of heat transferred to the mine air from these sources and through the use of efficient ventilation with effective cooling systems. The heat emitted by mining equipment and vehicles contributes a significant proportion to the combined heat load of an underground mine. This is especially a problem for diesel equipment due to the fact that besides heat, a large amount of water vapor is produced, which increases the humidity in the production workings. Diesel engines have proven advantageous in recent history due to their high power output and reliability. However, as mines continue to become more mechanized and deeper the climatic problems introduced by elevated heat generation will continue to rise. With that, the issue of heat generated by diesel equipment must be addressed.The economic alternative for diesel engine equipment fleets in underground mines is the electric engine. Technological advances in battery technology, increased mechanical output and improved reliability have made the electric engine significantly more competitive in comparison to diesel engines. Because electric engines do not utilize internal combustion, the heat produced by them is significantly less than the diesel engines. Battery-powered mining equipment likewise eliminate diesel particulate matter (DPM) produced by diesel engines. Utilizing battery electric equipment in underground mines provides many advantages, such as: (a) reduced heat load, (b) healthier and safer environment for the mine workers and (c) reduced mine operating costs due to lower ventilation requirements"

Jan 8, 2018

By E. Watkins, V. Gangrade

Large-opening stone mines often rely on natural ventilation and a network of auxiliary fans to produce adequate ventilation conditions in the mine instead of main mine fans, which are commonly utilized in coal mines. Large air volumes in underground stone mines, poor ventilation practices, and low operating budgets for mine ventilation potentially increase mine workers’ risk for dust, silica, and diesel particulate matter (DPM) emissions exposure. To help improve mine ventilation practices, the optimal auxiliary fan location for maximum airflow production from a ventilated intersection was determined using a combination of field measurements and computational fluid dynamics (CFD) modeling. In this study, conducted by researchers at the National Institute for Occupational Safety and Health (NIOSH), airflow quantity and fan data were collected at a partner mine to be applied as CFD model input parameters and comparison data for model validation. A six-foot diameter auxiliary propeller fan was introduced into the validated CFD model at three locations at a mine entry intersection with established ventilation flow perpendicular to the fan direction. Placing the fan on the opposite side of the intersection from the target active face area produced the highest ventilation flow rates at the downstream locations tested and produced the lowest amount of air re-circulation. The findings show that optimizing the placement of an auxiliary fan may increase the net effective ventilation flow rate by 70,000 cfm and reduce recirculation by 26%, which maximizes the potential effectiveness of large-opening stone mine ventilation systems and decreases mine worker exposures to airborne contaminants.

Mar 2, 2022

By B. Birol, M. N. Saridede

"Slag density is a significant factor in determining the process efficiency of the electroslag remelting (ESR) process, where calcium fluoride (CaF2)-based slag is formed synthetically to refine metal ingots. Although there are some former studies investigating the density of CaF2-containing slags, the prediction models focusing on them are applicable only to some specific systems. The present study aims to build a model to predict density for a wide range of CaF2-containing ESR slags. To investigate density for various slag compositions, CaF2-Al2O3-based and CaF2-Al2O3-CaO-based slag compositions were prepared. Additionally, some minor constituents like FeO, MgO and MnO were added to a 5:3:2 CaF2-Al2O3-CaO slag in order to investigate the effects of these constituents on the slag. The volumes of the prepared slags were measured in a tube furnace at 1450-1550 °C using the sessile drop technique, and their densities were calculated. The results showed that for the slags, density is related to optical basicity, and therefore a prediction model based on an Arrhenius equation was built. The model was tested with data from literature, and its limitations and validity are discussed.IntroductionThe electroslag remelting (ESR) process is a refining method in which a metal ingot is remelted under a synthetic slag. These synthetic ESR slags are mainly composed of calcium fluoride (CaF2), calcium oxide (CaO) and aluminum oxide (Al2O3). Other constituents like iron oxide (FeO), magnesium oxide (MgO), manganese oxide (MnO) and chromium oxide (Cr2O3) are added to this system in relatively low amounts, according to the type of steel ingot to be refined. The prediction of slag properties, such as electrical conductivity, viscosity and density, is crucial for the selection of the synthetic slag in order to obtain the required process parameters, like temperature, the passing time of the molten metal droplet through the slag, and metal-slag separation (Akbari, Reitz and Friedrich, 2009; Hara and Ogino, 1981; Mattar, El-Faramawy and Fathy, 2002; Mehrabi, Rahimipour and Shokuhfar, 2005; Presoly, Korp and Schneider, 2008).As slag density affects metal-slag separation in the ESR process, predicting the density of an ESR slag is important for appropriate refining and improved product quality. Although there are many studies investigating the density of slags (Akbari, Reitz and Friedrich, 2009; Aune, Hayashi and Sridhar, 2005; Hara and Ogino, 1981; Matsushita, 2011; Mills and Keene, 1987, 1981; Seetharaman et al., 2013; Shu, 2007; Shu and Chou, 2013; Sikora and Zielinski, 1974; Xu et al., 2012; Zhang and Chou, 2010), the prediction models built are generally valid for oxide-containing slags (Aune, Hayashi and Sridhar, 2005; Bottinga and Weill, 1970; Mills and Keene, 1987; Seetharaman et al., 2013; Shu, 2007; Xu et al., 2012; Zhang and Chou, 2010). These models were built on either the molar volumes of the constituents (Bottinga and Weill, 1970; Mills and Keene, 1987) or the thermodynamically calculated enthalpy or free energy of mixing, which can be applied to a system containing constituents sharing an ion, such as an O- ion for oxide systems (Aune, Hayashi and Sridhar, 2005; Hillert, 1980; Persson et al., 2007). Some recent studies modeled the density of some oxide slags on their optical basicity (Shu, 2007; Shu and Chou, 2013; Xu et al., 2012; Zhang and Chou, 2010)."

Jan 1, 2016

By M. McPherson, G. Danko

Methods of measuring in situ rock thermo-physical properties are rapidly evolving. Among those existing in the literature, a particular measurement procedure was selected for further development. The measurement is based on creating a spherical temperature field in a drill hole using a point source heater of constant heat flux. The bivariate temperature distribution 0 (r, t) is measured at several points along the length of the drillhole, radius r from the heater and at particular time intervals (t). A number of different evaluation methods were tested for calculating the unknown thermal conductivity (k) and diffusivity [] from the measured temperature and the known heat flux. The results showed that evaluation using the finite difference scheme and small temperature differences measured at points close together, cannot give a reasonable result. In order to solve the problem a new general analytical evaluation method is developed. Using an appropriate technique, it is possible to simultaneously obtain values for k and [], incorporating a semi least square technique to reduce the uncertainty in the evaluation. The new device and evaluation method makes it possible to obtain from a single drill hole highly precise k and [] values within an 8 hour period. The method has been used in several underground mines in the U.S. with good results.

Jan 1, 1987

By D. R. Wilburn

This summary of international mineral exploration activities for the year 2009 draws upon information from industry sources, published literature and U.S. Geological Survey (USGS) specialists. The summary provides data on industry 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 by the mineral industry based upon these data. Two types of information are reported and analyzed in this annual review of international exploration for the year 2009: 1) budgetary statistics expressed in U.S. nominal dollars provided by Metals Economics Group (MEG) of Halifax, Nova Scotia, and 2) information on regional and site-specific exploration activities that took place in 2009 and were compiled by the USGS. The MEG information summarizes planned company budgets for worldwide exploration activities in 2009, primarily for base metals (copper, lead, nickel and zinc), diamond and precious metals (gold, platinum-group metals and silver). Information on uranium exploration was included in the MEG overview for the first time in 2007, although this information was not included in the USGS analysis prior to 2008. The MEG survey methodology was changed in 1999 to include companies with exploration budgets greater than $100,000, as well as those companies included in prior studies whose anticipated budgets were above $2.9 million. MEG estimates that its post-1999 surveys cover at least 90 percent of world nonferrous nonfuel mineral exploration budgets. The 2009 survey is reported by MEG to cover an estimated 95 percent. Companies who chose not to participate in the MEG study, private companies that do not publish data and government-funded exploration activities make up the majority of the remaining 5 percent. MEG included 86 more companies in its 2009 survey than it did in 2008.

May 1, 2010