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By F. L. Pirkle, D. L. Pirkle, E. C. Pirkle, W. A. Pirkle

Heavy minerals have been mined from the sands of the United States’ Atlantic Coastal Plain since the early part of the twentieth century. Production of ilmenite from beach sands near Mineral City (Ponte Vedra), Florida, began in 1916. The first reported large-scale recovery of zircon in Florida was reported from this deposit in 1922 and of rutile in 1925. These operations ceased in 1929. Today the Ponte Vedra Country Club and Golf Course is situated in the center of the former mining site. In 1942 heavy-mineral operations were established on 202 hectares of land situated in Duval County, Florida. The location is about 16 kilometers east of the center of Jacksonville, Florida, in an area known as Arlington. This operation demonstrated that low-grade sand containing only 2 to 3 percent titanium minerals could be concentrated economically with the Humphreys spiral and that the oxides could be separated from the heavy silicates by electrostatic methods. Much of this area is now covered by a large mall and is a major retail- commercial center. Between 1958 and 1964 the Skinner tract, a deposit about 4 kilometers south of the above deposit, was mined. Today the area of this deposit is known as Deerwood, a gated country club community on the southside of Jacksonville. Further inland, E.I. du Pont de Nemours and Co. has been mining heavy minerals from a physiographic feature known as Trail Ridge since 1948, and a deposit near Green Cove Springs, Florida has been in production since 1972. Since the start of heavy-mineral mining in the southeastern United States, nine heavy-mineral ore bodies either have been or are being exploited in Florida and Georgia. Other deposits either have been lost to mining or are yet to be mined. These deposits have different origins. Some formed along shorelines at the heights of marine transgressions while others formed on regressional beach ridge plains during periods of temporary stillstands or slight transgressions. These different origins are reflected in the chemical and physical characteristics of the deposits. Ilmenite in older, more western deposits has a higher TiO2 content than ilmenite in younger, more eastern deposits. TiO2 content does not very with north-south direction. Garnet and epidote are absent or rare in the older Trail Ridge deposits, but progressively become common in the younger Duval Upland, Crestal Pamlico, and Holocene deposits. Grain size is coarsest for Trail Ridge sediments and finest for sediments in Duval Upland and Crestal Pamlico deposits. The average grain size for Holocene deposits is intermediate between Trail Ridge and Duval Upland deposits. The two models for the origin of the heavy-mineral deposits – deposits formed at the height of major marine transgression; and deposits formed during periods of temporary stillstands or slight transgressions that occur during a general marine regression; - are consistent with known sedimentological data and depositional trends.

Jan 1, 2005

By Murray Jacobson

A method for determining airborne trona dust concentrations using a midget impinger was developed. During sampling, the trona dust, composed of sodium carbonate and bicarbonate, dissolves in the collecting medium (water). Resulting solutions are then titrated using 0.1 [N] hydrochloric acid solution. The mass concentration of the trona sample is determined from a calibration curve relating the volume of acid required for neutralizing a collected sample to the mass of the dust. Test results obtained using this method are equivalent to those obtained using a gravimetric sampling method.

Jan 1, 1971

New Bio-Adsorber with Activated Carbon and Nano Tube Carbon for Separation of Nickel and Cadmium

Sep 13, 2010

By Thomas O. Meyer

Laboratory test results are presented for the determination of elastic modulus made with the NX borehole jack. Determinations were made in massive pieces of aluminum so as to satisfy conditions of linear elasticity, homogeneity, and isotropy. Results indicate a large discrepancy (approximately 200 percent) betwen material modulus as determined by laboratory block-loading tests and that indicated by the jack under relatively ideal circumstances. Effects due to interface friction, finite block size, incomplete plate-bore contact, and other factors were examined and found not to be significant. Finite element results indicate that assumed loading conditions for the jack differ from those actually occurring, at least in materials of high elastic modulus (approximately 10 million psi), such as quartzite.

Jan 1, 1974

Thallium is an uncommon heavy metal that may be found in concentrations that exceed regulatory limits in mining influenced water associated with processing cadmium, copper, gold, lead, and zinc ores. This study evaluated cost-effective modifications to lime precipitation treatment to reduce thallium concentrations to below the EPA drinking water MCL of 2 ppb. The oxidative precipitation of Tl+ to Tlß+ by potassium permanganate was explored for thallium removal at low concentrations (1 ppm initial thallium). Laboratory batch tests were performed to evaluate the removal of thallium from synthetic solutions. Three ratios of potassium permanganate to oxidizable metals in solution were used (one-half, one and two times stoichiometry). Thallium was removed to less than 1 ppb for all stoichiometric ratios evaluated within 10 minutes of reaction. The efficacy of oxidative precipitation for thallium removal is presented.

Jan 1, 2011

By A. M. Poston

Introduction of radioactive elements into ore samples and/or pregnant liquors and radiometric tracing thereof have greatly improved control of fusion and extraction studies on beryllium ores and products. Extractive metallurgical research on beryllium, normally guided by the usual laborious analytical methods, is both costly and slow. Recognition of this problem by the Bureau of Mines led to the development and application of radioisotope tracer techniques" as a substitute for chemical analysis at the Salt Lake City Metallurgy Research Center, The result was that much faster progress at significantly lower cost was achieved. This report discusses the problems encountered and resolved in using radioactive tracers and radiometric methods, defines the conditions and techniques for their effective use, and delineates the limitations and flexibility inherent in applying such methods in laboratory-scale beryllium research.

Jan 1, 1962

Stress induced, gravity-assisted failure processes typically dominate long before stress levels approach the strength of the intact rock (at approximately smax > 0.4UCS where smax = 3s1 ? s3 and UCS is the Unconfined Compressive Strength of the intact rock (Martin et al. 1999)). Under these conditions, discontinuities typically become clamped and the failure process becomes brittle. This brittle failure process is dominated by new stress induced fractures growing subparallel to the excavation boundary. While it is possible to identify areas with the potential for brittle failure, for example, using the general assumption that brittle failure will occur in areas at right angles to the major principal stress (Hoek et al., 1995), when the threshold smax > 0.4UCS is reached in areas around the tunnel boundary, or elastic modelling and the Hoek-Brown brittle parameters proposed by Martin et al., (1999) (i.e. m? 0 and s ? 0.11), amongst others, recent observations discussed by Everitt & Lajtai (2004), and Kaiser (2005; 2006) suggest that brittle failure processes are enhanced when structural features such as joints, weakness zones, bedding planes or foliations are preferentially orientated around the excavation boundary creating stress raisers which in turn facilitate the stress-driven rock mass disintegration process (e.g., as illustrated by Everitt & Lajtai (2004) on Figure 1b). Such weaknesses induce stress heterogeneities that thus promote tensile-spalling failure processes (Diederichs 2000). The observations suggest that stress induced damage can occur ?prematurely? depending on the orientation of micro and macro structures in situations where the known stress conditions should not yet initiate brittle failure processes. In general, when structural features (micro and/or macro), especially foliations, are present in a rock mass, the strength is effectively reduced, largely due to tensile strength heterogeneity in areas depending on the orientation of the structural features with respect to the excavation boundary. As a result, stress induced damage could occur in areas not normally considered due to the influence of anisotropy (Figure 1).

May 1, 2009

By S. E. Haszko

SEVERAL new XGa2 intermetallic compounds, Table 1, where X is a rare earth, having the AlB, structure were prepared as part of a continuing study of the magnetic and structural properties of rare-earth alloys.' In this note, the crystallographic results of these compounds are presented. Chart, Eq. 121 for the data in Fig. 1 can be adequately represented by The corresponding standard free-energy change is AF; = -4.576 T log K = -20,900 + 10.20T [5I At low nitrogen concentrations the ratio of mole fraction to weight percentage is a constant so that the mole fraction X of nitrogen is given by X = 0.0392 [%NJ. At low values of X, the activity and the concearation approach each other, hence K, = 0.0392 K,, where K, is expressed in terms of the mole fraction of nitrogen. Hence Eqs. [4]. and [5] become

Jan 1, 1962

By S. K. Chan, C. Badeen, S. Goldthorp, H. Feng, I. Alilovic, R. Turcotte

Over the last few decades, water-based explosives and their precursors, despite their apparent insensitivity, have been involved in a number of accidents around the world. A large proportion of these accidents occurred when these emulsions were pumped either for their manufacture, transport, or handling. In Canada, this has led to the development of “Guidelines for the Pumping of Water-Based Explosive”, which state that “using pumping pressures well below the laboratory measured minimum burning pressure (MBP) of the corresponding emulsions or watergels is a good safety practice”. However, in the above document, there is no description on how the MBP should be measured. In the last few years, a research program at the Canadian Explosives Research Laboratory (CERL) in collaboration with Orica has been focused on the development of a validated measurement protocol for realistic MBP measurements.

Jan 1, 2014

By P D. Katsabanis

The dynamic tensile strength of geomaterials is known to be highly dependent on the strain rate of the load applied. This is significant in applications where the material is subjected to shock waves and impact loading. This paper proposes the use of a simplified method to determine the dynamic tensile strength of hard brittle rocks using an explosively impacted version of the Hopkinson Pressure Bar. A compressive stress wave was propagated in a sample, representative of the material of interest, by detonating a small charge at one end of a cylindrical sample. The tension wave, generated upon reflection at the free face, causes spalling in brittle materials. Strains at four points in the specimen were continuously measured and the dynamic tensile strength was determined by applying the one-dimensional wave theory.

Jan 1, 2010

By A. J. Buchan

The wear of steel pipelines used for the transportation of backfill slurries is frequently regarded as an erosion problem only. An investigation was undertaken of the likely contribution to the total 'wear rate' made by corrosion. Use was made of a pipe flow loop with catholically protected specimens and corrosion inhibitors. Laboratory electrochemical tests utilizing a rotating-cylinder electrode were also conducted. The slurries used were classified tailings from two mines at a relative density of 1,7. The velocities were between 2 and 4,9 m/s. Substantial decreases in the wear rate of up to 80 per cent for one slurry and up to 67 per cent for the other were obtained with the use of corrosion control, showing that corrosion and, more importantly, interaction between erosion and corrosion, contribute a significant portion of the overall wear in steel pipelines

Jan 1, 1994

Kroemer(1-3) and Kroemer et al.(4) define the isoinertial technique of strength assessment as one in which mass properties of an object are held constant, as in lifting a given weight over a predetermined distance. Several strength assessment procedures possess this characteristic. Most commonly associated with the term is a specific test developed to provide a relatively quick assessment of a subject's maximal lifting capacity using a modified weight-lifting device.(1,5) The classic psychophysical methodology of assessing maximum acceptable weights of lift is also considered an isoinertial technique under this definition.(6) While the definition provided by Kroemer(1) and Kroemer et al.(4) has been most widely accepted in the literature, some have applied the term "isoinertial" to techniques that differ somewhat from the preceding definition, such as in a description of the Isotechnologies B-200 strength testing device.(7) Rather than lifting a constant mass the B-200 applies a constant force against which the subject performs an exertion. The isoinertial tests described here apply to situations in which the mass to be moved by a musculoskeletal effort is set to a constant. Is Isoinertial Testing Psychophysical or Is Psychophysical Testing Isoinertial? As various types of strength tests have evolved over the past few decades, some unfortunate developments in terminology have arisen to describe and classify different strength assessment procedures. This is particularly evident in sorting out various tests that have been labeled "isoinertial." One example was cited earlier. Another problem that has evolved is that the term "isoinertial strength" has two connotations. The first is the conceptual definition: isoinertial strength tests include any strength test in which a constant mass is handled. In practice, however, the term is often used to denote a specific strength test in which subjects' maximal lifting capacity is determined using a machine and a constant mass is lifted.(1,5) Partially as a result of this dual connotation, the literature contains references to both "isoinertial strength test" as a psychophysical variant(8) and the psychophysical method as an "isoinertial strength test" (4,9) To lay the framework for the next two chapters, the authors will briefly discuss some operational definitions of tests of isoinertial and psychophysical strength. In stating that the isoinertial strength test is a variant of the psychophysical method, Ayoub and Mital(8) refer to the specific strength test developed by Kroemer(1) and McDaniel et al.(5) Clearly, this isoinertial protocol has many similarities to the psychophysical method: both are dynamic; weight is adjusted in both; and both measure the load a subject is willing to endure under specified circumstances. However, while both deal with lifting and adjusting loads, there are significant differences between the psychophysical (isoinertial) technique and the Kroemer-McDaniel (isoinertial) protocol in their procedures and the use of the data collected in these tests. For our purposes, we designate the

Jan 1, 1998

By R. H. Duval

"In May 1936, Pamour started producing gold by cyanidation of flotation concentrates, and in 1939 was milling about 1, 600 tons per day.Refining records dating from 1939 show two oil-fired furnaces in use, (Rockwell type 46 11 x 29 11 inside oval shell).Refining time averaged 7. 83 hours during the year 1939, indicating a complete refining shift of about 9. 33 hours. That year appears to be characteristic of the period with regard to time required and results obtained.For that year total fineness (gold + silver) of the bars averaged 940 (approx.), but it frequently dropped below this figure, sometimes far below.Furnace lining life varied widely from three to seven or more months. Sillimanite was the standard lining but Mullfrax 41 was frequently used.For many years refining practice remained practically unchanged, and in 1960 procedure still consisted essentially of mixing a flux(% Composition Borax 41, Silica 11, Soda-Ash 11, Nitre 15, Mn02 22) with cyanidation precipitate in the ratio of l. 2 to l and heating to a medium heat (yellowishred, 2000° F) with a low flame for a long time. Time required was about 10. 5 hours per refining. Results were still much as detailed above.At this time it was decided to revise refining procedure, in an effort to shorten refining time and obtain consistently good bullion fineness."

Jan 1, 1965

By I. Mihajlovic

This paper investigates a potential method for arsenic removal from copper concentrates using hypochlorite leaching. The problems concerning pyrometallurgical processing of copper concentrates with high arsenic contents are discussed. A possible solution to the problem by leaching of natural enargite crystals with sodium hypochlorite under alkaline oxidizing conditions, with enargite converted into crystalline CuO and the soluble arsenic forming AsO43-, was experimentally investigated and results are presented. Kinetic parameters were calculated for enargite leaching, using a model-free approach. Advanced isoconversional methods were used to investigate the dependence of activation energy (Ea) on reaction rate (a). Keywords Enargite, copper concentrate, isoconversional method, kinetics, activation energy.

Jan 1, 2011

By Nixon C. A

The exploration of Mount Isa Mines' new copper source will require the development of a five kilometre 4.7 x 5.5 metre blind decline commencing 1000m below the surface and extending to 1600m below the surface. With virgin rock temperatures approaching 60¦C, the ventilation strategy represents a complete departure from any previously used at this mine, in that refrigeration becomes essential. The use of direct water to air cooling techniques has become commonplace in mines throughout the world and their application is being adopted at Mount Isa Mines. A heat load simulation routine has been implemented to allow for the design of refrigeration requirements, as well as to aid in the selection of diesel or electric equipment. This enabled planners to determine the size of a surface based refrigeration plant. Future refrigeration demand for expansion into the ore production stage has also been investigated.

Jan 1, 1988

By J. Evans

Including: Tailings thickeners, CCD?s, paste thickeners, HI-rate thickeners, lamella thickeners, high compression thickeners, clarifiers etc. Flocculant dosing control for mining thickeners and clarifiers is influenced by a number of process factors. 1. Flow rate into the thickener or clarifier a) As the flow rate increases into the thickener or clarifier ?retention time? decreases which causes a greater affect hydraulically on the settling solids. So as the flow rate increases it will generally mean an increase in flocculant dosing rate. b) As the flow rate decreases into the thickener or clarifier the retention time increases which reduces the hydraulic affect on settling, improving settling rates. This will generally mean that as the flow rate decreases, we will decrease the flocculant dose rate.

Jan 1, 2011

By G. K. Derby

Five different types of drilling systems were developed under the flexible drill program that was initiated by the Federal Bureau of Mines to protect roof bolter operators. The systems were designed for underground coal mines with seams as low as 30 inches, and with roof bolts longer than the height of the seam opening. Four of the developed systems were true flexible drills; the fifth was a remote-controlled, automatic rod changer concept. Only two of the five firms successfully completed testing requirements under the original contracts: BendixCorp.,4 with a true-flex drill; and Ingersoll-Rand Research, Inc., with the rod changer concept. The Bendix drill was rated best, and the Ingersoll-Rand drill was rated second. Because of the closeness of the ratings and the vast differences in the two development concepts, both systems had sufficient potential to justify further development funding for design updating and testing. Also, both systems warranted consideration for inclusion into other ongoing development projects under both safety and energy directed programs.

Jan 1, 1978

By I F. Bell, K P. Hammerschmid

Well planned and executed environmental management plans can reduce life-of-mine operating costs and the need to deal with major environmental issues at the time of mine closure. With proper planning during the exploration, feasibility and execution phases of a project, final closure costs can be reduced. The reduction of closure costs should be considered during exploration and initial feasibility studies and when process facilities, waste rock dumps and tailings impoundments are designed. During the mining of the resource, closure cost reduction will depend on effective and efficient environmental management plans for ongoing land clearance, segregation of mine waste materials, management of mine site water and workshop wastewaters, and the establishment of progressive rehabilitation strategies. These issues are the responsibility of planning, production, technical support and maintenance personnel at an operating site. The successful implementation of environmental plans will ensure that all impacts are reduced and that closure issues with major cost implications are addressed prior to closure of the mine.

Jan 1, 1995

By J. H. Clemes

The process of leaching silver ores with sodium hyposulphite is comparatively new, and published accounts of the details and losses of the process are as yet very few. The following account of a careful series of experiments to determine the actual loss in this process may therefore be acceptable to members of the Institute. The ore treated was highly calcareous, and the principal sulphide present was iron pyrites. Following is an analysis by Professor Price, of San Francisco, of the ore treated : Per cent. Silica,..........15.13 Sulphur,.........13.31 Arsenic,.......... 9.82 Iron............ 17.33 Alumina,..........1.35 Zinc,...........4.92 Lead,..........1.78 Carbonate of lime,..33.78 Magnesia,.......... 2.58 100.00 Ten tons were crushed dry with a 30 X 30 screen = 900 holes per square inch. In order to feel our way with this ore, two experimental or "pilot" charges were roasted. Pilot Charge No. 1. Treated 1000 pounds in a four-hearth reverberatory. 8.30 p.m.—Entered fourth hearth, remaining there one and onehalf hours; sulphur began to burn. 10 p.m.—Changed to third hearth; ore became red-hot half an hour after entering; the fireplace was kept almost destitute of fuel. 2.30 A.M.—Changed to second hearth. Charge continued, giving off a large quantity of sulphurous fume; the fireplace was kept dark.

Jan 1, 1884

By L. D. Tracy

"The first study of this subject has been made in Illinois, but as opportunity affords, similar studies will be made in other States. It is hoped that the data obtained will assist the coal—mining industry to standardise the forms of leases, and so avoid some of the abstruse and ambiguous clauses which may be found in many of then and the consequent liability of costly litigation.In some of the publications of the Illinois Mining Investigations prepared under a cooperative agreement with the U. S. Bureau of Mines, the Illinois State Geological Survey and the Engineering Experiment Station of the University of Illinois, the coal areas of the State have been dividedinto eight geological districts, each district being treated separately.report covers District No. VI of that classification, and it is hopedstudies of the other districts will be completed in the near future and similar results published.The report includes a short description of the geological condition the character and quality of the coal and the nature of the surface, data for which have been taken largely from the Illinois Geological Survey publications.Mining methods and percentages of recovery are mentioned, together physisal conditions, market and transportation facilities, because all of these factors have a bearing on royalties and leasing conditions."

Jan 1, 1926