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By Dae S. Young

The Disjunctive Kriging (DK) procedure was developed to estimate ore recovery figures within a deposit/ domain from limited diamond drill hole (DDH) core assay data taken at the exploration stage. Local recovery figures include minable ore tonnage and ore grades within relatively small areas such as stopes or small panels on a pit bench, for a given cut-off grade. The grade and tonnage should be computed based on the true selective mining units, that is, the average grade distribution of selective mining units within a panel. Local recovery figures are critical information for economic and engineering feasibility studies before mine development, as well as for short-term mine planning for operating mines. This kind of information can be provided only by non-linear geostatistical methods including DK and the Multivariate Gaussian Approach (MG) (Journel, 2, Parker, et al, 5).

Jan 1, 1982

By Charles A. III Cravotta

Streamflow and water-quality data for the northern part of Swatara Creek, which drains a 112-km2 area in the Southern Anthracite Field of east-central Pennsylvania, indicate iron, copper, and lead, and to a lesser extent manganese and zinc, are transported with suspended particles during stormflow conditions. During stormflow conditions, concentrations of these constituents typically peak prior to peak stream stage as a result of scour and transport of streambed deposits. In contrast, sulfate is transported mostly as a dissolved ion. Concentrations of sulfate, specific conductance, and pH are inversely related to streamflow, indicating dilution and acidification during stormflow. This effect is attributed to the mixing of poorly buffered stream water having pH 6.0-6.5 with weakly acidic storm runoff having pH 4.0-4.5 and low dissolved solids.

Jan 1, 2000

By L. Piga, G. Belardi, V. Alesse, N. Shehu, J. Freund

The physico-chemical interactions among minerals such as olivine, chromite and serpentine; the most commonly present ions in solution such as Ca and Mg; and flotation reagents such as EDTA and oleic acid were investigated. The study was conducted via release tests, electrophoretic measurements and microflotation of selected minerals coming from the Kukes deposit in Albania. The results were confirmed in beneficiation tests on two ores, one from the Kukes (Kalimash) deposit and the other from the Rizo deposit in Greece. It was demonstrated that, when Na-oleate is used as collector, chromite, olivine and serpentine can be separated at pH 2.5 and/or pH 5.5 when employing ethylenediamine tetraacetate (EDTA) on previously deslimed material. This approach ensures flotation concentrates with a Cr203 content better than 50% with a recovery of more than 75%.

Jan 1, 1998

By Lucien Duckstein

The purpose of this paper is to give recommendations for utilization of water resources in a mining region, considering also water supply and environment; the case study of mining for coal and bauxite under the karstic aquifer of the Transdanubian mountain of Hungary is used to illustrate the approach, which consists in formulating a static multiobjective control model and solving it by compromise programming. The three activities of regional mineral resource exploitation, water supply and environmental protection are represented by different objectives which cannot be expressed in commensuerable units. Thus, a solution which is optimal for one objective is usually far from being optimal with respect to the other two objectives. As a result, we are not seeking an optimal solution for the conjunctive regional system, but a good compromise, trade-off or "satisfactum" (1), (2).

Jan 1, 1979

By R. A. Wharton, Z. Yang, R. W. Smith

The electrokinetic and flotation behavior of the green alga Chlorella vulgaris was studied in the absence and presence of Pb(II), Al(III) and flotation collectors. It was found that the presence of Al(III) is necessary for good flotation of the organism, whether or not Pb(II) is present, when dodecylammonium chloride or sodium dodecylsulfate is used as collector. Best flotation using dodecylamine is at about pH 8, and best flotation when using sodium dodecylsulfate is at about pH 4. It appears because of the small size of the organisms that the Al(III) is necessary for flocculation to enhance bubble-cell contact and C. vulgaris removal from water. When N-dodecyl-2-aminopropionic acid is used as collector, good flotation occurs at about pH 4 without the addition of Al(III).

Jan 1, 1992

By I. K. Gilmore

PCS Phosphate operates an open-pit phosphate mine in the central coastal plane of North Carolina. The company has mining and refining facilities located on the south shore of the Pamlico River. Phosphate ore is recovered at the Aurora facility by open-cast mining techniques. Walking draglines and bucketwheel excavators remove the overburden and mine the phosphate ore. The mined ore is slurried about 8 km (5 miles) to the processing plant. At the plant, the phosphate ore slurry is passed through screens to remove material coarser than 2 mm (10 mesh) and then pumped through hydrocyclones to remove material finer than 75 mm (200 mesh). The resulting phosphate and sand mixture is treated with various reagents and subjected to an anionic flotation process. A cationic flotation process removes the sand from the final phosphate concentrate.

Jan 1, 1995

By L. G. Sobral, J. E. Hoffman, T. J. Keefe, A. J. Monhemius, O&apos

The kinetics of electrodeposition of gold from dilute solutions of alkaline KAu(CN)2 at different gold and free cyanide concentrations on a gold rotating disk electrode were investigated by use of a steady-state linear potential scan technique. The design and performance of a laboratory electrowinning cell with a reticulated nickel cathode, operating in the flow-through mode, for the removal of low levels of gold ions from aqueous cyanide media is described. During the batch recirculation of oxygen-free gold cyanide solutions, the gold concentration was reduced from 10 ppm to <0.5 ppm with current efficiencies of up to 80%. The influence of solution flow rate through the cathode and of the pore size of the reticulated nickel foam is discussed. The removal of gold ions from solutions of low ionic strength was also investigated.

Jan 1, 1993

By T. E. Garnar

Heavy mineral mining has been a small, but important Florida industry over the past sixty years. Early geologic history of each deposit is similar up to point of deposition in alluvium, deltaic sediments, or along shorelines. Later geological development through reworking and concentration is different for each deposit. The Trail Ridge deposit was formed by reworking Citronelle sediments of the Lake Wales ridge. Post depositional leaching of iron from ilmenite makes Trail Ridge an important source of titanium minerals for TiO2 pigment manufacture. Research leading to the separation and sale of by-product heavy minerals from Florida deposits has been important in maximizing profitability. Advances in mineral dressing technology will lead to future mining of lower grade reserves. Future needs for heavy minerals seem certain to expand, with increased activity in exploration and development of mining operations.

Jan 1, 1972

By Qun Wang, Elena A. Alonso, Janusz S. Laskowski

Primary normal long-chain amines are insoluble in saturated brine. Their colloidal solubility (dispersion) in concentrated electrolyte solutions is strongly affected by the presence of surfactants (frothers). This paper shows that a better usage of alcohol type surfactants, which are commonly used in potash ore flotation as frothers, can significantly improve the flotation of both coarse and fine sylvite particles. A new process of potash ore flotation is developed, which includes premixing an effective frother with an aqueous solution of amine or emulsion of extender oil containing amine. With such a combination of flotation reagents, KC1 particles up to 5 mm in size float very well in the short flotation column, and particles up to 2 mm float in a mechanical cell; when used to treat fine fraction-containing sample, this method may as well provide an improved concentrate grade.

Jan 1, 1995

By A. K. Sheik, W. G. Pariseau

A small underground mine in northern Idaho was used as an experimental facility for studying the role of water in the analysis of mine opening stability. Laboratory test data, borehole measurements and geological mapping assisted in constructing a coupled finite element model of the rock mass. The model was used to make quantitative estimates of: 1) rock stress, strain and displacement changes, and 2) water pressure and flow velocity changes that occurred during historical mining. Stope cuts and wet fills were included in the analysis. Stability of crown pillars between stopes was of particular interest. The relatively low effective stress and high rock mass strength showed that water pressure changes were of no great consequence in agreement with experience. The computational tools used in the analysis may be applied to other wet mines with appropriate changes to site-specific input data.

Jan 1, 1999

By D. C. Durgin

Located near Ely, Nevada, the Robinson Mining District has produced gold since 1868 from the Ruth? porphyry copper system. Gold occurs in at least seven different deposit types, including porphyry copper ore, silica-pyrite replacements along favorable horizons, fault controlled silica bodies, intrusive breccias, stockworks in bornfels and in retrograde skarns. In all of these the primary controls localizing gold ore are structural .preparation and permeable hosts. Indicator elements associated with gold are Ag, As, Te, and to a lesser extent Sb and Tl. Pb, Zn and F are peripheral to gold or with it depending upon position within the system. The district has produced 87,000 kg (2.8 million ounces) of gold thus far. An additional 19,300 kg (620,000 ounces) of reserves are established, and well over 31,100 kg (1,000,000 ounces) of reserves are anticipated. I

Jan 1, 1989

By F. Ferella

In this paper several leaching tests were per-formed to optimize the leaching section of a hydrometallurgical process for the recycling of alkaline and zinc-carbon batteries. Zinc and manganese oxides were dissolved by an acidic-reductive leaching using sulphuric acid and oxalic acid as reductant. Leaching tests were developed according to a full factorial design. The operational variables were pulp percentage, sulphuric acid concentration, temperature and oxalic acid concentration. Additional tests were performed to evaluate the precipitation rate of Mn and Zn oxalates. Finally a hydrometallurgical process were proposed for the recycling of alkaline and zinc-carbon batteries, in which Zn and MnO2 are recovered from purified solution by electrowinning: Zn is recovered as metallic compound, while Mn can be recovered as electrolytic manganese dioxide (EMD), but recovery of further manganese compounds is possible with simple process changes.

Jan 1, 2006

By J. Ugarte-Núñez

Biodiversity assessments that are developed in different stages of a mining project, have different objectives that define the methodology to be used in each of these stages. In this way, we define two stages of a project: 1) the time at which assesses the state of biodiversity or biological components, before any intervention in the project area, previously defining the area of direct influence and indirect influence of the project for each biological group to be evaluated and 2) the time when certain groups or biological, are monitored during the developmental stages of the project with you to obtain information about the level impact they may have, for project activities. It discusses the methodological differences that must be used in both biodiversity assessments: to develop biological baselines and in those assessments aimed at monitoring different components of biodiversity.

Jan 1, 2011

By Harrison A. Schmitt

During .the past five decades or so we have passed from a time when it was difficult to point to a mine or an ore body and verify that it had been discovered by geological methods, through the. Twenties when the common saying was, "Who ever heard of a mine found by a geologist?", to recent decades when hundreds of mines and ore bodies are acknowledged geological discoveries and the above query can be ignored. Recently, however, the application of mining geology appears to have been downgraded, or so it seems to me. Basic geology in mining has been cheapened and glossed over in favor of geophysics and outcrop sampling, even though the latter is merely one technique of mining geology and, to some extent anyhow, has been used for a. long time. (Locke, 3, pp 81-87). Geophysics by itself and in conjunction with geology has had success in certain geological provinces, but limited attainment in mountainous terrane except in those few cases where strongly magnetic minerals are associated with ore. Nevertheless, in the Cordillera .many experimental techniques are offered as proved ones. This is not an intent to try to depreciate honest geo- physics. Continued experimentation and use of it is approved by all, but at the same time it is foolhardy to throw mining geology overboard, Generally both approaches should be considered and usually, at first anyhow, geology is the most direct one.

Jan 1, 1960

By Sheldon P. Wimpfen

Back in 1970 Congress passed the National Mining and Minerals policy Act, which had as one of its basic tenets to rely on a strong and stable private minerals industry for the development and production of our mineral resources. Since then, a substantial amount of legislation has been introduced that impacts on the minerals industry. Although most of the bills proposed are not passed into law, each bill affecting minerals and mining is given careful review by the Bureau of Mines. Comment is forwarded with the object of being helpful to legislators by providing our assessment of the probable impact of each bill proposed along with suggestions to improve them. Actually few bills introduced become law. For example, in the 93rd Congress 4,260 bills were introduced in the Senate and 17,690 in the House. In the final accounting there were passed 123 private laws and 649 public, 3 percent of the bills introduced. There would be little merit here in attempting to analyze each mineral-related bill that was proposed. Many are similar and aim at making a certain aspect of our minerals activity fit needs. So, to simplify the task the many bills have been grouped by subjects. Slide 1 shows the principal topics and the number of related bills introduced. Putting it altogether, there are 26 principal subjects and almost 200 bills. And these numbers are probably off somewhat, as this accounting was made early in December.

Jan 1, 1976

By D. E. Ranta, John G. Stone

One of the steps in an ore reserve estimate is customarily a rigorous calculation of the in situ grade of the orebody itself. The result of this calculation is usually reduced by some purely arbitrary factor to force the calculation to agree with the observed grade of ore actually mined. The failure of the calculation to realistically depict the grade of ore actually extracted is in many instances not the result of either an incorrect calculation procedure or of sloppy mining practice, but is a direct consequence of unsuspected irregularities in the contact between the orebody and the surrounding wall rock. A pattern of holes spaced at 1.5-3.Om foot intervals, drilled as part of a pre-development program, will often reveal that a presumed "regular&apos; ore/waste contact is, in fact, so highly irregular that it will be next to impossible to separate ore from waste during mining. In such an instance, &apos;fingers&apos; of waste projecting into the mining block will substitute for equal volumes of ore left outside the mining limits. As a result, the grade of material actually mined will be less than the grade envisioned for the orebody. The volume of waste substituting for ore in the mining block is about 0.4X, where X = the average error in projecting the ore/waste contact between alternate holes in the test pattern, and is expressed in units of volume per unit of area of the contact surface.

Jan 1, 1992

By Michael Mccorkle

The Turnkey Project contracting approach is a very viable project delivery system for many mine and mill owners. Generally speaking, the Turnkey Project approach makes sense when the owner knows what it wants, is willing to accept the contractors judgement on process elements and maintenance standards, and early construction completion/facility stmt-up are of primmy importance. Projects with unclear process and project objectives make poor candidates for true Turnkey applications. If the objectives are unclear, under development or significant refinement, the owner's effort should go into a good schedule "A" package allowing Engineering, Procurement, and Construction (EPC) contractors to develop cost and schedule proposals for the final design ( engi­neering), procurement and construction of the facility. Figure 1 and 2 graphically depict (in general terms) the stan­dard Design-Bid-Build, Construction Management (CM) Fasttrack, EPC, and Turnkey Approach.

Jan 1, 1998

By Gary L. Simmons

Many large (refractory) sulfide gold resources exist in Nevada and other parts of the world that are not amenable to conventional flotation concentration using air as the flotation gas medium. Over the past five years Santa Fe Pacific Gold Corporation (SFPG) has investigated flotation process options to economically treat refractory ores and resources of this type at its Lone Tree and Twin Creeks mines. Conventional flotation technology applied to the original high-grade gold resources at Lone Tree and Twin Creeks was initially unsuccessful. Review and analysis of auriferous (gold-bearing) iron sulfide mineralogical characteristics and flotation ..:hemistry provided a fundamental understanding that led to the development of a new flotation process that SFPG refers to as N2 TEC. This paper discusses the development of this technology and compares N TEC results with conventional flotation practice.

Jan 1, 1997

By Mark L. Blanford, Roger M. Zimmerman

INTRODUCTION Volcanic tuffs on and adjacent to the Nevada Test Site (NTS) are being considered by the Department of Energy (DOE) for the possible geo- logic disposal of high-level radioactive wastes. The Nevada Nuclear Waste Storage Investigations (NNWSI) project was established in 1977 to evaluate such disposal. Sandia National Laboratories (SNL), one of the participants in the NNWSI project, has as one of its responsibilities the development of a rock mechanics program for the Nevada site. SNL conducted three small-diameter heater experiments in welded and nonwelded tuffs in G-Tunnel on the NTS, to investigate the thermal (heat transfer) and hydrothermal (thermal- induced water migration) behavior as part of the rock mechanics program. These two aspects were investigated to increase knowledge about the behavior of tuff so that predictive capabilities are available for use by repository designers, waste-package designers, and performance analysts. Also, knowledge of the behavior of the tuff is invaluable for planning and designing future in situ experiments at Yucca Mountain, the candidate site for the repository. The evaluations of these three experiments is the subject of this paper. Designers, analysts, and experimenters are seeking a better understanding of the behavior of tuffs under the influence of thermal loads expected from radioactive-waste storage, because of two physical features peculiar to tuffs. First, tuffs are inherently porous because of the manner in which they are deposited (Smith, 1960). Tuffs utilized in G-Tunnel testing have porosities ranging from 15 to 46%, which cover the ranges of expected porosities in the target horizon at Yucca Mountain. It has been established that the G-Tunnel tuffs have similar bulk, thermal, and mechanical material properties to those at Yucca Mountain (Zimmerman et al., 1984), thus, G-Tunnel testing can be used to evaluate the effects of porosity on the thermal and mechanical behavior. The second feature is that tuffs above the water table contain pore water that influences the thermal properties of the rock; displacement of the water must be accounted for in repository designs and analyses. For example, G-Tunnel tuffs, located some 600 m above the static water level, have saturations in excess of 60%. Similar percentages are expected at the target horizon in Yucca Mountain (Zimmerman et al., 1984). The presence of and the removal of the pore water affects the thermal behavior of the tuffs, and these three experiments were designed first to determine the phenomenological behavior and then assess influences on predictive capabilities. The focus in this paper is to present the results and evaluations of the experiments as they apply to improving predictive capabilities. The thermal aspects are emphasized by comparing the measured temperatures (in and around heater emplacement holes) with calculations of predicted temperatures using numerical models, so that the effects of significant parameters can be evaluated and integrated into future predictive models. Observation of the hydrothermal aspects is needed to assess the effects of loss of pore water and subsequent migrations on the temperature fields during the heating, and also to define the expected environment in the vicinity of the outer metallic surface around the waste. The metallic boundary can be either the outer shell of the waste package system, which is the main engineered barrier for waste containment, or the borehole liner. A final decision has not been made as yet about the necessity for lining boreholes; thus, the emphasis is on predicting the characteristics of the environment around the outer metallic surface. Two aspects that limit the scope of this paper are (1) the experiments were performed at a smaller than canister scale for the purpose of

Jan 1, 1986

By Henry J. Jacoby

This report concerns Contract No. 3B of the Port Richmond Project, for the Department of Water Resources of the City of New York. It involves the construction of 7, 000 ft. of 7 ft. finish I. D. interceptor sewer by tunneling in soft ground, as well as associated manholes, regulator chambers, siphons and miscellaneous sewers and structures, beneath a heavily travelled perimeter road in Staten Island. The Contractor is Richmond Constructors, a joint venture of Grow Tunneling Corp., sponsor, MacLean Grove & Company, Incorporated, Morrison-Knudsen Company, Inc., and Andrew Catapano Co., Inc. Project manager is Paul DeMarco, Vice-President of Grow Tunneling Corp. The cortract, as designed and bid, requires the use of liner plates 101 -0" O. D., and both cast iron and steel designs of several widths were included in the bid documents by the owner. The specifications also required the contractor to install and put into operating condition, prior to commencement of mining, a complete low pressure compressed air plant and all accessories for mining in compressed air, even though the contractor was given the option of using other methods of ground water control. A third requirement of the specifications was that a shield be used, either manual or mechanical, and with full provision for "breasting". BACKGROUND The first soft ground shield driven tunnel in the United States was in New York City and was built under Broadway in lower Manhattan in 1869

Jan 1, 1974