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By Craig J. Nelsen, David A. Smith

In 1987, LAC Minerals (USA), Inc. conducted a high resolution helicopter electromagnetic (EM) and magnetic geophysical survey on the Ortiz Mine Grant, New Mexico. The primary purpose of this survey was to assist in geologic mapping of a major structural zone, the Tijeras-Canoncito Fault System (TCFS). This structure is a very important ore- controlling feature in the area. Geophysical signatures over known deposits was a secondary goal of the survey, but direct detection of mineralization was not anticipated. The TCFS was revealed to be a complex, branching and anastomosing system of faults which locally form the bounding structures of a graben. The geophysical survey guided subsequent geologic mapping by redirecting field investigations, and geophysically redefining some features which previously had been only partly defined.

Jan 1, 1989

By John Batty, Rennie Stallknecht, Dave Dew, Rennie Marais

GENCOR was contracted by Lonrho Plc of London to design a treatment plant for the benificiation of ores from the Amantaytau Goldfields in Uzbekistan (CIS). The testwork required for determining the design parameters was conducted at GENCOR Process Research in Randburg South Africa, on large bulk samples of ore shipped from the CIS. The initial milling and flotation testwork was designed to both optimise the conditions for maximum gold recovery, and to provide flotation concentrate for subsequent testwork. The concentrate produced was fed to a pilot scale BIOX® plant, and at the client's request a portion was shipped to specialists in roasting and pressure oxidation technology for comparison. Besides the testwork conducted at the GENCOR Process Research Laboratories in South Africa, the client also requested that the testwork be repeated at the Ingichki Research centre in Uzbekistan to demonstrate to their CIS joint venture partners that the results obtained in South Africa are reproducible and to demonstrate the ease of operation of a BIOX® plant. Pilot scale equipment was air freighted to Ingichki where the results of the testwork obtained in South Africa were successfully duplicated. BIOX® technology was shown to achieve higher gold recoveries than either roasting, whole ore roasting or pressure oxidation.

Jan 1, 1995

By Houston Kempton, Tim Dyhr, Andy Davis, Mark Bloom, Connie Travers, Dave Atkins, Jeff Deen

INTRODUCTION Historical mining activities in the Robinson Mining District, in the Egan Range of east-central Nevada (White Pine County), resulted in five open pits (Veteran, Tripp, Liberty, Ruth, and Kimbley Pits), several large mine-waste dumps, and numerous underground workings developed for copper, zinc, gold, lead-silver, and manganese (Figure 1). Groundwater percolating downward through the copper sulfide ores produced a blanket-like supergene zone enriched in copper, which has been one of the primary objectives of mining since the early part of this century. To obtain permits for future operation, an EIS was conducted that evaluated future pit- lake chemistry, groundwater quantity and quality issues, transport of water and solutes subjacent to a proposed tailings impoundment, and the potential for waste dump acidification. AREA HYDROGEOLOGY The mine area is on a ridgeline draining to the Steptoe Valley to the east and to the White River Valley to the West. Precipitation in the Robinson Mining District ranges from a low of 15 cm (6 in.) per year in the valley to more than 50 cm (20 in.) per year in the surrounding mountains. Evapotranspiration exceeds precipitation, leading to a net loss of water from the basin as either surface flow or underflow to the north at Currie, Nevada (Eakin et al. 1967). The White River Valley, which lies to the south and west of the mine area, includes approximately 4,200 km2 (1,620 mi2) of the upper part of the Colorado River Basin. This valley is 112 km (70 mi) long, 32-48 km (20-30 mi) wide, and like Steptoe Valley, evaporation and transpiration exceed precipitation (Maxey and Eakin 1949). The local groundwater flow system in the Robinson Mining District and the proposed mine area is dominated by two main components: (1) a groundwater mound or high between the Ruth Pit and Murry Springs, and (2) a shallow groundwater flow divide that follows the ridge crest south of Ruth, which contains the Veteran and Tripp pits. Besides the alluvium, the main hydrostratigraphic units controlling groundwater flow are limestones, shales, and sandstones, along with the intrusive quartz monzonite stocks. Based on the piezometric surface measured in October 1993, three distinct groundwater regions were identified. In the Giroux Wash area, an apparent fault runs between WCC-G1 and WCC-

Jan 1, 1995

By Lane White

The nature of the new Mining Law in Mexico, how it works and its implications for foreign investors were discussed from a variety of points of view by speakers participating in SME's special programming on Mining in Mexico at its An¬nual Meeting in Albuquerque, NM Feb. 14-17, 1994. Following are summaries of three papers whose primary objective was to give foreign investors some insight into the nature of doing business under the current Mexican Mining Law and its regulations. Lane White, Publisher.

Jan 1, 1994

By P. Zhang

Previous studies have shown that separation of clay minerals from non-clay minerals is the key to economic recovery of the phosphate from the waste phosphatic clays (slime) which represent about 20- 300/0 of the phosphate mined. Small hydrocyclones of different sizes (4" and 6") were tested for sizing the slime at +10 microns in order to remove most of the clay minerals. The effect of design variables and operating parameters were evaluated. Multi-stage cycloning and the effect of dispersant were also investigated. Chemical and mineralogical analyses of different size fractions of both the underflow and overflow samples indicated satisfactorily separation efficiency.

Jan 1, 1998

By Brij M. Moudgil, Shoulian Zhu, J. L. Pinault

A new technique, prompt neutron activation probe (PNAP), for analyzing phosphate rock slurry in-situ was evaluated both in the laboratory and at the plant. The technique yielded a high precision in the analysis of Ca, Si and H using 252Cf source. Low accuracy of the direct measurement of P using 241Am/Be in the laboratory tests was attributed to the interference of rare earth elements present in the samples, particularly Gadolinium. No significant effect of variables such as solids loading, particle size distribution, and flotation reagents was observed on the probe performance. The probe can detect the compositional changes of the feed, tailings and the concentrate streams in the plant.

Jan 1, 1993

By Ernest Koenigsberg

In 1961 Lerchs and Grossman presented a method, based on graph theory, to determine the optimum ultimate pit limits for an open-cast mine. At the same time they demonstrated a dynamic programming algorithm for the optimum pit limits for a two-dimensional open-cast mine. Since then many methods for determining optimum limits for three-dimensional mines have been programed, and even more have been reported in the literature. The methods include computer "simulation" of the manual methods used by engineers, the development of sets of conic sections and fitting to exclude overlap, integer linear programming (and its equivalent network flow model), and dynamic programming. Many of the methods do not guarantee optimal solutions but seem to satisfy the user. Other reported methods have never been applied, partly because they did not yield optimal solutions. We have developed a three-dimensional dynamic programming algorithm which requires a single pass through the data. Large problems can be solved on a small computer because only a small part of the data is required at any time. In this paper we will review the state of the art and to demonstrate the connection between linear programming (and network flow) models and the dynamic programming method.

Jan 1, 1982

By Irina Melekestseva, Beltenev. Victor, Victor Ivanov

"One of the major problems discussed over the last years is a possibility of mining of seafloor massive sulfide deposits. In spite of the pessimistic points of view on their commercial development, they are still of great interest and continue to be studied (Hannington et al., 2011). Recently, Barriga (2012) paid special attention to the underestimated amount of massive sulfide hydrothermal fields and pointed to the importance of the buried fields and subseafloor mineralization.This study examines the geochemistry of seafloor and subseafloor precipitates collected at the Peterburgskoe (19°52´ N) and Irinovskoe (13°20´ N) hydrothermal fields (MAR) during the 34th cruise of the R/V Professor Logatchev in 2011. These fields were discovered by the Polar Marine Geosurvey Expedition in 2010 and 2011, respectively (Shilov et al., 2011; Beltenev et al., 2012). The Peterburgskoe field, associated with basalts, is located 16 km west of the main rift valley at the depth of 2800-3100 m at the junction of a large non-transform discontinuity with the second rift ridge parallel to the rift valley. The Irinovskoe field occurs at depths of 2700-2850 m and has a northwestern satellite sulfide site, both confined to an oceanic core complex (MacLeod et al., 2009), which includes mafic and ultramafic rocks. The details of geological structure of the fields may be found in the relevant papers.Diverse samples were collected from the hydrothermal fields: seafloor massive sulfides, Fe-hydroxide crusts, SiO2-rich sulfide-bearing precipitates, and subseafloor mineralized rocks (Melekestseva et al., 2014a). Massive sulfides may be subdivided on the Fe-rich and Cu-rich types. The marcasite-pyrite, pyrite, hydroxide-marcasite, and chalcopyrite-pyrite (Fe-rich) mineral types are dominant in the Peterburgskoe field at lesser amounts of sphalerite-hydroxide-chalcopyrite and pyrite-covellite-chalcopyrite (Cu-rich) massive sulfides. The mineralized sulfide-talc-carbonate-chlorite, chlorite-sulfide-quartz, and hematite-sulfide-quartz rocks host stringer-disseminated sulfides including chalcopyrite, covellite, and pyrite."

Sep 1, 2014

By J. C. Cawley, J. Sottile, J. L. Kohler

Control circuit failures contribute significantly to continuous miner downtime. The time required to put the machine back into production is a function of the time required to diagnose the problem, obtain parts and make the repair. Of these, the diagnostic time is often the largest. A microprocessor-based system with the ability to diagnose all of the common control circuit failures was designed, installed on a continuous miner and tested. This paper summarizes the development of the diagnostic system and provides examples of the system's diagnostic capabilities. Implementation issues and the hardware used for the prototype are briefly described. Comments on the system's performance are also presented.

Jan 1, 1995

During foundry sand reclamation process development, molds formed from reclaimed chromite sand showed a rapid decline in tensile strength during thermal cycling tests. Because this characteristic could limit reuse of chromite sand in the foundry, the sand was examined in detail. Scanning electron microscopy, x-ray mapping, magnetic susceptibility, and x-ray diffraction were utilized to evaluate processed chromite sand. It was found that process variables such as binder composition, reclamation temperature, and processing method had a significant effect on the chromite sand particle surface. X-ray diffraction indicated a crystallographic change in the processed sands. Magnetic susceptibility also increased after processing. Diffusion of iron to the particle surface and increased surface roughness were identified as potential causes of the decreased tensile strength in the molds.

Jan 1, 1993

By E. M. Cukrowska

The evaporative pan complex consists of two adjacent seasonal pans. These pans carry an exceptionally high salt (TDS) load due to over 50 years of effluent discharge via the pipeline from mines. The nutrient, heavy metal, radionuclide load in the water and sediments of the pans are very high affecting groundwater around the pans. The groundwater in the region contains TDS > 40 000 mgl-1 and sulphates > 7000 mgl-1, whereas groundwater in areas assumed to be unpolluted by mining activities have TDS < 500 mgl-1 and sulphates < 200 mgl-1. The extent of continuity between the pans and the groundwater is unknown, although there appears to be seepage of contaminated groundwater into the river system.

Jan 1, 2006

By Arash Habibi, Anna Cable, David Loring, Aleksandar D. Bugarski, Logan Ingalls, Calvin Rutter

The results of diesel particulate matter (DPM) monitoring were used by the underground mining industry to mitigate adverse effects of exposure to DPM. NIOSH Method 5040, currently used for ambient and personal exposure monitoring, does not provide needed real-time information. The objective of this study is to develop a methodology for continuous monitoring of DPM concentrations in an underground environment, founded on the application of the Dekati electrical particle sensor (DePS). The DePS, which measures concentrations of submicron aerosol in real time using a diffusion-charging sensor, was evaluated by comparing the results of the concurrent measurements with reference methods at several locations downstream of the diesel-powered equipment. The DePS results were found to correlate well to those obtained by reference methods. However, it was found that dependence of the response on the physical and chemical properties of aerosols necessitates sitespecific correlation factors for the targeted matrices. The site-specific factors for number and mass of diesel aerosols were derived using the results of concurrent measurements with TSI NanoScan, FLIR Airtec, and carbon analyses performed on the concurrently collected filter samples. The results showed that methodology based on compensated DePS measurements would be suitable for continuous monitoring of DPM in underground mining operations.

Dec 1, 2022

By Fritz Grübl

Modern shield TBMs allow tunnel drives through almost any type of ground. Thanks to high elaborated technical measures, significant subsidence of the ground surface can be almost entirely avoided. The tunnel lining behind the TBM must be capable of withstanding all loads without deforming, especially during ring erection and advance. Single-shell tunnel linings behind the TBM, usually reinforced concrete segmental rings, can be designed to fulfill this demand. With many projects, however, damage occurs to the lining. Repair costs may be extremely high. Reasons for damages and possibilities to avoid them are shown and explained.

Jan 1, 2001

By P. K. Davis, B. Gharib

The results of a previous basic study of the flow and design characteristics of hydrocyclones demonstrated that a recovery as high as 99% with a product rating* of 0.95 can be achieved on a batch+ basis with a single, water-only cyclone if it is configured properly. The next logical step was to demonstrate continuous processing of gob for the efficient recovery of coal by means of a laboratory-size demonstration system. A project to design and construct such a single-¬cyclone system was sponsored by the US Department of Energy, which also sponsored the initial study. A recovery of 93% with a product rating of 0.89 was demonstrated. The system design and the data taken are discussed.

Jan 1, 1990

By S. A. Bunk, W. P. Wood

In the early 1980's BHP identified several potential gold deposits in West Africa. One of these deposits was located in Mali, near the village of Syama. As a result of extensive explo­ration activities, an oxide ore as well as an underlying sulphide ore was identified. After agreement with the government of Mali was reached the development of the deposit was undertak­en. The plan for the development of the mine included the treat­ment of the oxide ore followed by the treatment of the underly­ing transition and sulphide ore. The development of the deposit was extremely aggressive. Following the approval of the project in early 1989, engineer­ing was started, equipment purchased sitework was started, and the first ore was introduced in December of 1989. This was accomplished in spite of the difficulties of the site. These diffi­culties included: • remote site location without air or road or water access • no existing infrastructure including water, power, or communication • high health risks • limited construction and manufacturing support in West Africa The operation began with a conventional crushing/grind-ing/CIL/elution and electrowinning facility. The facility was designed to treat 2000 metric tonnes of ore per day. After start­up in December of 1989, the operation was improved to the point that plant throughput was averaging nearly 3000 tpd and running at 92 to 93% availability.

Jan 1, 1996

By N. Edmonson

During the last 30 years, a dramatic increase in the supply of byproduct sulfur substantially reduced the share of the market held by Frasch-mined (non-by-product) sulfur in North America. Even though Canadian sulfur production is not discretionary, the geographic remoteness from the large US markets and the high transportation costs associated with delivering sulfur to those markets has meant that Canadian producers act like discretionary producers in many important ways. They have effectively replaced the US Frasch producers as the cost-marginal sulfur source to large US markets. Implications of this change in market structure include more volatile sulfur prices and longer sulfur price recessions.

Jan 1, 1997

"?irovski Vrh" Uranium deposit in Slovenia is type of mineralized sediments in ore bearing belts of deflected S-structure, in which the belt is less than 25% mineralized. Ore bodies of irregular small thickness, unreliably contoured, made difficult estimation of correct contours, which are necessary for design and exploitation works. The deposit was explored by vertical boreholes made at the surface and by boreholes fanned from drives. For the purpose of application of this estimation method, 1 m composites have been made in slices which were parallel to the referential belt plane. Estimation was made for 1,5m x 1,5m x lm blocks which do correspond to the size of the containers in the ore transport stage. Two variables have been used: the first, indicator of function (ore=1, waste material =0) and kriging method; the second, logarithmical content of Uranium and Minimum Mean Square Error Estimation (MMSEE) method. Based on estimated values of those variables, probability of ore quantity as well as Uranium content over determined cut-off were calculated for each block. Those two parameters enable determination of the most probable form of the ore body in ecah one metter slice. Estimation of sixteen small blocks in a large 1,5m x 1,5m x 1m block made possible estimation of ore quantity and its content for the determined cut-off, as well as categorization of exploration. This method is being used for estimation of ore reserves and planning of exploration operations. The described&apos; methodology was tested in an exploitation block.

Jan 1, 1986

By D. Panias

Alumina hydroxides such as gibbsite (Al(OH)3) and boehmite (AlOOH) are precursors of many types of alumina that find important industrial applications. The thermal decomposition of AlOOH, which is a more energy saving precursor compared to gibbsite, gives rise to the formation of ?-, d-, ?- and a-aluminas that are used for the production of catalysts. The applications of the aluminas are governed by their properties that are a function of the precursor material and its microstructure. The microstructure in turn is a factor of the method and conditions applied, as well as, in the case of soft chemical processes, on the anions present. Towards these ends, this study was focused on the effect of different anions on the physicochemical characteristics of the alumina hydroxides precipitated in the first 5 minutes after the perturbation of the stability of a supersaturated sodium aluminate solution (Bayer liquor).

Jan 1, 2006

By Andrew M. Garvie, William W. Plotnikoff, Eugenia Y. Kuo

Water infiltrating the surface of waste rock dumps transports pollutants into the environment. Lysimeters have been used to quantify the infiltration rate. To date their design has been guided by modeling under steady-state conditions. Recently a two-dimensional finite element code has been developed to model the response of lysimeters to time-dependent infiltration rates. It was used to investigate the response of lysimeters installed in a waste rock dump and subject to a monsoonal rainfall pattern. The results are presented and compared with field data.

Jan 1, 2000

By C. H. Bucknam

Acid neutralization titrations were applied to the characterization of soil and overburden for the control and prediction of acid rock drainage in the coal fields of the eastern United States in the 1970?s (1). These became known as the Sobek methods as a result of the early United States Environmental Protection Agency publication and the methods have been modified (2) to be adapted to many applications in the metal mining sector (3,4,5,6,), and, as a result, there are a large number of acid neutralization potential methods being used that are referred to as Modified Sobek methods. Standardization of neutralization potential methods for metal bearing ores and related materials based on carbonate carbon, rather than titration, commenced in the 1990?s through the American Society of Methods and Materials (ASTM) Committee E01 on Analytical Chemistry for Metal Ores and Related Materials Subcommittee E01.02 on Ores, Concentrates and Related Metallurgical Materials (7). A subcommittee section, E01.02.05 on Environmental Methods, was organized to coordinate the method and material standardization efforts of ASTM and the Acid Drainage Technology Initiative Metal Mining Sector (ADTI-MMS) Prediction Committee (8), which took on the project of standardization of the acid neutralization potential acidity titration method (ANPA) to supplement the carbonate carbon method in E1915 (9) for application to samples which have metal carbonates (10), in particular, which result in overestimation of the neutralization potential using the carbonate carbon methods (11).

Jan 1, 2010