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By William E. Bonini

Gravitational field anomalies have been observed over many igneous intrusives of medium (4000 km2) to small (100 km2) size in outcrop area. These studies give good results because the residual anomalies can be separated from larger scale crustal anomalies and density contrasts usually are present. Although unique solutions are not possible, the analysis of the gravity anomalies can put limits upon the geologic interpretation of such bodies. Three examples in Montana, U. S. A. are discussed: (1) the Boulder Batholith, a late Cretaceous quartz monzonite series of intrusives of 4000 km2 outcrop area; (2) the Little Rocky Mountains, an up-domed area, in which an Eocene porphyry (130 km2) has intruded the Precambrian crystallines and lower Cambrian sediments; and (3) the Crazy Mountains, an Eocene diorite (100 km2), which has intruded the Paleozoic and Mesozoic sediments. In both the Boulder Batholith and the Little Rocky Mountains, intrusive rocks are less dense than the surrounding rocks and negative anomalies are found (40 and 28 mgal, resp.). In the Crazy Mountains, the intrusive is more dense than the surrounding sediments and a sharp positive residual anomaly of 42 mgal is observed. The analyses of the gravity anomalies predict that: (1) the thickness of the Boulder Batholith is on the order of 10 to 15 kms and is concave upward; (2) the Little Rocky Mountain syenite is not a simple laccolith, but is T-shaped and extends in depth to about 16 kms; (3) the Crazy Mountain diorite is not a simple small scale series of stocks, but a large connected body extending in depth 5 kms to the basement (although nothing can be said of it within the basement because there is little density contrast). The analyses of the anomalies place important limits on both the areal and depth extent of the intrusive bodies. Of all possible geophysical techniques, gravity studies offer the most promise in the determination of the shape in depth of intrusive bodies.

Jan 1, 1969

By James J. Komadina

INTRODUCTION Newmont Gold Company's Rain operations are located in Elko County, Nevada, approximately 9 miles southeast of the Town of Carlin.The property was submitted to Newmont Exploration Limited in 1979 and underwent development drilling over the course of the next four years, culminating in the completion of a project feasibility study in October 1986. Initial project scope included development of an open pit mine, an 815,000 DSTPY heap leach, a 572,000 DSTPY mill (Mill No. 3), and associated support facilities. Approval to proceed was given by Newmont Gold Company management in June 1987. Detailed engineering began in early July, followed immediately thereafter by procurement of major equipment components through various second hand sources. PROJECT DESIGN Keep It Simple In early August, Newmont Mining Corporation, parent company of Newmont Gold Company, became the takeover target of an "investor" group headed by T. Boone Pickens. Details of the ensuing events have been well documented by the press; suffice to say their impact on this project was material and required immediate flowsheet changes. Project design throughputs were increased to 1,000,000 DSTPY and 760,000 DSTPY for the heap leach and mill, respectively, in mid- September. These changes caused major project headaches as all general arrangement drawings had been approved and structural steel as well as concrete contracts were in place. Additionally, ground breaking was to commence in two weeks time! Rain project management assembled shortly after the announced changes, to devise an engineering and construction strategy capable of handling these new business conditions. The project had been justified using a gold price of $325 per ounce with a forecasted overall cash cost per ounce of $230. Hence, strict control of capital expenditures was necessary to maintain development economics. Mill start-up had also been moved forward one month, to August 1, 1988. To meet an already ambitious schedule, construction techniques needed to be simple and proven as most of the facilities were planned for erection during winter at a site with design criteria of -40F and 90 mile per hour winds. Perhaps the most critical factor requiring consideration was that of personnel. Newmont Gold's revised business plan called for corporate-wide production increases from 587,000 ounces per year in 1987, to 1,400,000 ounces by mid- 1989. Labor requirements were forecasted to grow from 900 employees to over 2,100. This fact, in combination with the rapid growth of Nevada's gold industry, led to the expectation that turnover of operating personnel would be extremely high. It was concluded that, to meet cost, time, and operational goals, the necessary strategy could be succinctly put - "Keep It Simple." Mining/Metallurgical Factors The Rain deposit consists of three interconnecting mineable shapes with host rocks ranging from 90%+ barite to a highly silicified jasperoid. Due to a limited number of mining faces in the first two years, in-pit blending

Jan 1, 1990

By H. Vedrine

A modelling study has been carried out on the flotation of the Moinho (Portugal) polymetallic sulphide ore, based on pilot plant data. It shows that successfully modelling the flotation of such an ore needs to take into account not only the influence of particle size, but also that of the mineral liberation of the ore. The benefits deriving from the research have been twofold in that the study has: 1. Improved the understanding of (a) the response of the ore to froth flotation and (b) the influence of regrinding the zinc middlings; and 2. Provided models for the optimization of the industrial flotation circuits when the plant starts up in 1991.

Jan 1, 1991

By J. H. Elledge

Hydraulic Transportation of Phosphate Ore from, a 40,000 Cubic Yard per Day Strip Mine IMC is transporting 1500 yards per hour of phosphate ore in a water slurry a distance of approximately five miles from a strip mine to a flotation beneficiation plant at their Noralyn Operation. in Barrow, Florida. This ore, which consists of approximately 1/4 phosphate, 1/2 silica sand, and 1/4 clay slimes, is being pumped through a 20 inch O. D. pipeline using seven 20 and 18 inch GIW metal pumps direct connected to electric, motors. This paper details some of the problems involved and the specific methods used to accomplish this bulk material handling requirement.

Jan 1, 1966

By M. S. Celik

Salt-type minerals are usually floated with anionic and cationic collectors. Flotation of a number of systems has been reported to remarkably increase above the concentrations where surface precipitation of collector-metal salt is initiated. Some studies attribute this phenomenon to heterocoagulation of oppositely charged collector colloid and mineral particles. In this study, examples are given on boron minerals to demonstrate that the high flotation region occurs when particles, colloidal precipitates and bubbles acquire a similar charge which induces Van der Waals interactions resulting in hydrophobic bonding.

Jan 1, 1995

By J. E. Russell

The purpose of this paper is to describe an independent study which forecasts Texas coal production, specifically for electric power generation. This study, extending to the year 2000, is justified on the following basis. Texas produces and consumes considerably more electric energy than any other state, has consistently high growth rates in the population and industrial sectors, and has large lignite reserves. Also, since recent forecasts have been criticized as overly optimistic, this study is timely when considering the long lead times required in obtaining new power sources. In the study demand for electric energy was assumed to rest on two dominant factors: 1) overall state of the Texas economy as measured by the Texas Gross State Product (TGSP) and 2) Texas population. Demand models were prepared and tested following a study of several options. A final linear regression demand model with time lags for the two variables was chosen on the basis of good correlations. On the supply side, uncertainties such as impact of nuclear sources, gas-fired cogeneration, and ratio of imported to lignite coal exist. These uncertainties were studied with high and low cases for effects on lignite. Finally a simple supply model was chosen. Results of the study indicate that lignite production in Texas will rise from the current (1984) 40 million tons per year (XTPY) to the range of 77 to 124 MTPY and more probably 100 HTPY in the year 2000.

Jan 1, 1984

By James Paone

Subsidence movements have damaged houses, schools, streets, and public utility lines in some undermined sections of Belleville and Maryville, Ill. In cooperation with local officials and the State of Illinois, the Interior Department's Bureau of Mines is sharing experience in backfilling abandoned coal mines to demonstrate that bituminous coal mine workings in south-western Illinois can be successfully backfilled and subsidence-prone areas stabilized. Subsurface investigations revealed that mine workings are dry and underlain by underclay deposits susceptible to instability upon wetting. Backfilling will therefore be accomplished by pneumatic injection instead of the hydraulic methods used in previous subsidence-control projects.

Jan 1, 1977

By Byron R. Berger

Disseminated Au-As-Hg mineralization is localized along the Getchell Fault system at the Getchell Mine in north-central Nevada. Replacement ore bodies occur in Cambrian carbonaceous limestone and limy shale beds. Cretaceous granodiorite, dacite porphyry, and andesite porphyry dikes parallel the fault zone and are spatially associated with the mineralization. Hydrothermal alteration and mineralization occur continuously along 4-5 km of the fault system, and extend more than 1 km down-dip. Alteration consists primarily of removal of carbonate and deposition of quartz, pyrite, and carbonaceous material. Marcasite, sericite, kaolinite, calcite, barite, and fluorite are common. Gold content reaches more than 43 ppm in parts of the altered zones and averaged 9.3 ppm in the mined ore bodies. For the mineralized zones as a whole arsenic averages 0.28%, and occurs primarily as realgar, orpiment, and arsenopyrite. Mercury (22 ppm) is finely disseminated and mercury-bearing minerals are seldom recognizeable. Accessory mineralization includes antimony (100 ppm), copper (47 ppm) , lead (18 ppm) , molybdenum (10 ppm) , tungsten (16 ppm) , and zinc (50 ppm) . Geologic field studies and K-Ar dating suggest that the mineralization is related to a hydrothermal system produced by the granodiorite and related dikes.

Jan 1, 1975

By David S. Young

All pigments and extenders or fillers whether organic or inorganic fall into the following broad general classes: I. Colored II.-White III. Black IV. Metallic A pigment- is any particulate matter that is essentially insoluble and chemically unaffected by the media into which it is dispersed. According to this very broad definition, colored pigments, white pigments, fillers, extenders, and functional pigments would all be included. The particulate size range would also be quite broad ranging from very fine colloidal particles (~0.01µ) to relatively coarse particles (~100.0µ). This broad definition is usually subdivided into more practical divisions which tend to relate the classification of the pigment to its primary function in the system in which it is used. Hence, the word extender implies that its major purpose may be to extend the system.

Jan 1, 1985

By John Sasadi

Several years ago I wrote a comprehensive paper 'entitled, "Future Trend of Bulk Carriers" dealing with the principle dimensions of vessels and how they can be predicted; then with loading and unloading of large carriers, especially considering various designs of "Self Unloaders". Since writing the paper, many large bulk carriers were basically built along the, predictions made. Maximum size today is in the 150,000 DWT class, with few exceptions, which are combination carriers (ore-oil) or OBO's (oil-bulk-ore) in the 200-250,000 DWT class in the same paper, many references were made cautioning engineers not to design ports which could be "obsolete tomorrow", however, these were not always followed. Nevertheless, during the past few years many modern ports were built signaling the beginning of a new area of "Super Ports". Super Ports can be built for various reasons, most important to provide transfer stations where bulk material is received from large carriers then transferred to smaller vessels or barges for distribution. Obviously, opposite movement of bulk commodities can justify the building of "Super Ports", however, these are not as difficult to build for many reasons. The Material Handling Industry has developed efficient means of unloading smaller vessels or barges with continuous-type unloaders and has mastered the art of storing, reclaiming, and moving large quantities of bulk material to high-capacity shiploaders. Nevertheless, the industry has failed to design and market efficient ship unloaders which in any way could match the presently attainable shiploading rates. For these reasons, it is considerably more difficult to build "Super Ports" for incoming rather than outgoing bulk materials with large bulk carriers. The purpose of this paper is to elaborate on problems affecting high-capacity, continuous ship unloaders, especially involving large bulk carriers. For better understanding, some references will be made to the smaller, continuous barge or ship unloaders, but only as the principles affect the larger units. Additional references will also be made to exploit the present "State-of-Art" of the grab

Jan 1, 1972

By S. Mathur

Polyacrylic acid (P AA) was evaluated as a selective flocculant for dolomite-apatite system. P AA of 4 million MW was found to flocculate both dolomite and apatite. However, their flocculation behavior was significantly different with 450,000 MW PAA which was the lowest molecular weight fraction capable of flocculation. In single mineral tests, at a dosage of 2kg/t 90% of dolomite and 35% of apatite flocculated. Selectivity was achieved in mixed mineral tests where apatite of 90% grade at 70% recovery level was obtained in the concentrate from a feed consisting of 80:20 mixture of apatite and dolomite. The dolomite rejection was about 75% which corresponds to 1% MgO in the concentrate.

Jan 1, 1995

By Downing Terry L.

Dry mineral beneficiation methods have been developed for separation of borate minerals from montmorillonite claystone gangue. The methods include the use of newly developed dry high intensity magnetic separators. The application of these methods has the potential for economic benefit at U.S. Borax Inc. in three areas: ? Processing surface impoundments (ponds) material. ? Pre concentrating ore to be fed to primary refinery. ? Concentrating borate minerals to produce potential products.

Jan 1, 1995

By K. R. Griffin, K. D. Luxbacher, E. C. Jong

The schlieren technique describes an optical analysis method designed to enhance light distortions caused by air movement. The ability to visualize air flow has significant implications for analyzing underground mine ventilation systems, including the enhancement of surveys and models. Currently, traditional schlieren methods are impractical underground. Background-oriented schlieren (BOS) provides a solution to this problem. BOS requires two primary components, a professional quality digital camera and a schlieren background. A schlieren background is composed of a varying contrast repetitive pattern, such as black and white stripes. This background allows the camera’s sensor to capture minor light diffractions, such as those caused by air flow. Although BOS shows great potential for ventilation analysis, sensitivity is an issue. This paper seeks to validate the BOS technique for imaging flow through a regulator by comparing BOS images with traditional schlieren images. This paper also outlines initial experimental efforts used for the validation.

Jan 1, 2011

By M. M. Foss

Geophysical methods are gaining acceptance in the evaluation of coal mine ground control condition. The use of in-seam seismic investigations has contributed significantly to the body of information concerning ground control feature identification and analysis. Seismic methods have been used successfully in locating voids, faults, fracture zones, roof and floor rock interfaces, and more recently in characterizing in-seam stress distribution. Seismic tomography is an effective tool in data interpretation for several of these applications, but as is the case with other engineering application of geophysical techniques, there are limits as to how much substantive information can be interpreted from a given data set. This paper discusses some of the applications of in-seam seismic geophysical tomography, and the limits to which the transformation from raw data to information should be taken.

Jan 1, 1995

By Edward P. Larsen

At our annual meeting in St, Louis, Mo. in February 1961, we presented a comprehensive paper (No. 61-B-22) on the subject of "Blending and Handling of Materials for Agglomeration". In that paper you will find a discussion on the difference between "blending" and "mixing". With regard to "blending" we brought out the facts of its usefulness for the preparation o materials in an agglomerated mass to attain controlled chemical and physical uniformity. "Mixing" was discredited as not being useful for the attainment of uniformity of any kind.

Jan 1, 1962

By J. J. Kellar

The near-infrared (NIR) (12,000-4,000 cm-1) region of the electromagnetic spectrum, between the mid-infrared and visible, has often been viewed by spectroscopists to be of limited utility. This is unfortunate, and recently the use of the NIR has increased greatly, primarily for the quantitative analysis of food and agricultural products. However, many other areas of application of NIR spectroscopy remain unexamined. In this paper a novel use of NIR in the area of flotation chemistry is demonstrated. Specifically, it is shown that NIR/Internal Reflection Spectroscopy (IRS) can be used to quantify collector adsorption reactions in-situ.

Jan 1, 1990

By Richard B. Stein

This paper will present an overview of several hydrometallurgical processes which can be used for sea-nodule metal recovery and some simplified economics. Before going any further, here are some of the basic figures from which the economics were developed. The first is to establish a representative composition for a typical nodule feed (Slide 1). This set of chemical analysis figures can be taken as typical for a deep Pacific nodule feed and shows manganese at 30%, copper at 1.1%, cobalt at 0.2%, nickel at 13% and iron at 10% for the metals of economic interest1.

Jan 1, 1982

By James J. Brady, Kenneth L. Faught, Chadi El Mohtar, Chaoshi Hu

"During construction of a 9.5-ft. diameter sanitary sewer tunnel, the City of Edmonton encountered a large pocket of flowing sand that flooded their TBM and caused significant surface subsidence, stopping further tunneling by the TBM through this zone. A unique collaborative effort ensued between the authors representing the city, consulting engineers and academic researchers to develop the optimal strategy for grouting the problematic soils. The site has a layer of very find sand between 20 and 30 ft. in depth with fines contents ranging from 5% to more than 40%. The collaboration extended from requesting additional site investigation efforts to shipping samples to the UT-Austin laboratories for grout testing plus ground and grouting characterization tests resulting in field recommendations for a full scale ground improvement program. New research information on the grouting of fine sands along with a collaborative framework for the design of in-situ grouting projects are the key topics presented. INTRODUCTION Encountering a large unexpected pocket of flowing sand with an open-faced TBM while excavating a tunnel below the groundwater table is never a good thing. This was certainly true for the City of Edmonton when one of their Lovat TBM’s became inundated by flowing sand while excavating the 9.5-ft. diameter Millwoods Double Barrel Replacement Tunnel in September 2013. However, since the City of Edmonton self-performed this work, a rare situation existed where the site could be investigated objectively, without the prejudice of contending parties selectively influencing how information was gathered and presented, to accurately examine site conditions with a goal of identifying the best remediation measures."

Jan 1, 2016

By B. E. Davis

A problem that has continued to plague the Florida phosphate industry is the loss of coarse phosphate in the flotation circuit. Attempts to remedy this problem such as floating the coarse material (plus 425 µ m) in a separate circuit have resulted in limited success, but recovery is still not optimum. The Bureau of Mines is investigating ways to improve the recovery of coarse phosphate through improvements in the conditioning step. Studies to optimize conditioning parameters such as agitation energy, conditioning time, conditioner solids, and residual clay content have resulted in improved P2O5 recovery. Optimizing these and other conditioning parameters resulted in a rougher concentrate grading 30 pct P2O5 with a P2O5 recovery of 97 pct.

Jan 1, 1993

By John C. Ferm

The role of geology in coal exploration, mine planning and mine development has, in the past, been relatively small. The primary reason for this lies in. the simplicity of geologic concepts that were necessary to bring these operations about. These concepts can be briefly stated as follows: 1) coal occurs in the beds or layers and is overlain and underlain by shales, sandstone or limestone in varying porportions, 2) each coal bed has been given a name and certain quality characteristics can often be associated with a named bed and 3) coal beds (and their adjoining rocks) are often folded into broad anticlines or synclines and, in some places, displaced or faulted. In actual practice, however, these simple principles have been found wanting. Thickening, thinning, pinch outs or changes in coal quality occurred but the occurrence was apparently unpredictable and the only real solution to such problems seemed to be practice and experience. This combined with ingeneous engineering solutions have provided answers to most questions. Perhaps a more fundamental reason that geology could offer so little input to coal mining is that the thickest, most persistant and best quality coal seams followed the above stated rules fairly well. In many areas, however, such seams are now nearing exhaustion and the increased demand for clean, non-polluting, safe energy is quickly bringing a need for techniques of exploration and mining procedures that will make development of formerly unminable seams a profitable venture. For the past 20 years some considerable body of knowledge has been added to the framework of the geology of sedimentary rocks and it is the purpose of this paper to present some of these newer ideas that will be useful in solving some of the present problems of coal exploration and development.

Jan 1, 1976