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By Rihab Guellala

In Tunisia, the Paleocene-Eocene series has an important socio-economic interest. It contains profitable oil and water accumulations. Moreover, it encompasses phosphate reserves. The present study uses seismic reflection prospection and borehole data for the reconstitution of the Paleocene-Eocene deposit structure in the Jerid area (southwestern Tunisia), a crucial step for the phosphate exploitation. Firstly, lithostratigraphic correlations incorporating water and petroleum wells were established according to different directions for a tentative approximation of the Paleocene- Eocene deposit geometry by following their lateral evolution. To give more details, seismic reflection profiles were interpreted in the second step. The Paleocene-Eocene formations were associated with their corresponding reflectors on the closest seismic profile using the relation of time and depth in petroleum wells. Analysis of lithostratigraphic correlations shows notable variations in the Paleocene-Eocene series thickness and depth. Seismic profile interpretation explains these variations by highlighting different buried tectonic features. The results confrontation reveals that the phosphatic deposit geometry in the Jerid area is mainly influenced by the (1) emergence of the Saharan platform and the Chott northern chain since the Late Cretaceous, (2) syn-sedimentary normal activity of E-W and NE-SW faults during the Paleocene-Eocene epoch, (3) reverse-reactivation of these faults, and (4) major Tortonian folding phase. This study can enormously enhance the Jerid area socio-economic development by presenting useful findings that may orientate the phosphate exploration.

Aug 15, 2021

The nature of adsorbed calcium carboxylates (oleate and stearate) has been investigated by in-situ/ex-situ Fourier transform infrared internal reflection spectroscopy (FTIR/IRS). Previous spectroscopic studies in alkaline solution have shown that adsorbed carboxylate is characterized by a C-O stretching vibration at about 1550 em?1 for less than monolayer coverage. Similar results were found in this study. More specifically, in this study such a singlet at 1550 cm-1 was found for LB monolayers of calcium distearate transferred as a condensed layer at a high film pressure to the surfaces of fluorite and germanium. Normally the spectrum of bulk calcium distearate reveals a doublet at 1575 and 1540 cm-1, characteristic of a three dimensional 7-fold coordination for calcium carboxylate complexes. This doublet is generally found for carboxylate multilayers formed by spontaneous adsorption at the surface of calcium minerals. In this regard, the spectral evidence suggests that whenever the calcium dicarboxylate is constrained at a surface as a condensed layer, the 7-fold coordination can not be satisfied and the surface carboxylate is forced into a two dimensional symmetrical coordination with a singlet at 1550 cm-1. On the other hand, if the Langmuir-Blodgett (LB) monolayer calcium distearate film is transferred at a low film pressure the doublet is observed. This analysis is further confirmed by the spectral results for LB transferred calcium distearate monolayers at a hydrophobic silicon surface. Even though these are condensed monolayers formed at high film pressure, the carboxylate group, oriented away from the surface, is no longer constrained by the surface force field, and thus exhibits the characteristic doublet of the bulk calcium distearate salt.

Jan 1, 1998

By S. Gering, R. Ruiz, C. H. Calderon-Arteaga, J. Barrios

"Located in the northeast corner of Zacatecas State, Mexico, the Peñasquito operation is comprised of the Peñasco and Chile Colorado (Brecha Azul) deposits. Openpit mining (prestripping) began in 2010 and full production commenced during 2011. The openpit mines feed both a sulfide concentrator (mill) and a heap leach pad. The project is owned by Goldcorp Inc. Peñasquito is a poly metallic deposit with Au, Ag, Zn and Pb being recovered as payable metals.As a consequence of lower grade ores expected with advancing mine life, Peñasquito is facing a declining metal production profile. To maximize returns and asset value, plant modifications, including the addition of a carbon prefloat circuit and a pyrite leach circuit to improve recovery, are currently being undertaken. This carbon prefloat circuit will enable the recovery of precious and base metals from carbonaceous sediments. This material is currently being stockpiled. With the associated increase in complexity in the process circuit, the requirement of the ore control system to accurately predict ore feed characteristics is critical to maximizing metal recovery at the Peñasquito operation. The addition of the carbon prefloat circuit was also a key driver in allowing the Chile Colorado openpit to be developed.These conditions alongside Goldcorp’s drive to increase profitability and maximize net asset value has created challenges. These challenges are numerous and multifaceted. However, the ability to accurately route materials from the ore control system is critical to site success, and some of these challenges have been overcome by the adoption and implementation of a new ore control (OC) technology. Examples of these technological innovations in the ore control program are discussed in this article and include improvements in geomodeling, material routing and reconciliation. Successful implementation of these elements has led to significant improvements in selectivity, performance and data management, while reducing the variance between planning and execution, thus helping to drive overall improvement across the operation."

Jan 7, 2018

By G. S. Dobby

The Cu-Au flotation cleaning circuit at Freeport Indonesia consists of three stages: two flotation column stages, in series, followed by one stage of mechanical cells. Concentrate from both column stages is combined as final concentrate. The mechanical cell stage has two parallel rows of seven Wemco 500's. The Wemco concentrate is recycled to feed of the second column stage and Wemco tails report to final tailings. This paper examines cleaner circuit performance, focusing on size-by-size performance of the individual stages and the individual mineral groups -copper sulfides, gold and in sol minerals. The recovery mechanisms of insol minerals are examined.

Jan 1, 1995

By John B. Goddard

In-situ leaching of uranium by aqueous ammonium carbonate containing oxygen or hydrogen peroxide as oxidant results in the partial dissolution of sulfides. While some of the sulfide sulfur is oxidized to sulfate, a considerable portion is oxidized only to thiosulfate and polythionates. Polythionates poison the anion exchange resin used to extract uranium. At the Palangana operation in southeast Texas, the trithionate ion (S3062-) was found by infrared spectrometry to be the major resin poison. Treatment of ion exchange feed solutions with hydrogen peroxide only resulted in partial conversion of reduced sulfur species to sulfate, and trithionate conversion was particularly slow. Poisoning of the resin also occurred from the ammonium chloride eluant, which built up trithionate because of recycling. This was essentially eliminated by chlorinating the eluant prior to yellow cake precipitation.

Jan 1, 1984

By J. M. Keane

SMEThis loaner is concerned with important criteria relative to the design of small flota¬tion concentrators. For the purpose of this discussion a small flotation concentrator is defined as a facility having a designed ore feed rate of 1,000 metric tons per day (MTPD), or less. The decision to design and construct a small flotation concentrator is the culmination of a series of logical steps relative to the ex¬ploitation of a potential ore body. The information required for a rational and timely decision regarding plant design and construction is usually contained in a feasibility report. The information required in a thorough feasibility report has been summarized (1) (2) as follows: Type of mine or plant and proposed daily, monthly, and yearly production of all intermediate and final products. Quantity of indicated ore reserves. Location of project illustrated by a map showing surroundings, trans-portation facilities, and existing utilities.

Jan 1, 1980

By M. Ghiani

Biohydrometallurgy originated, some forty years ago, from an environmental problem, namely the serious pollution of the Ohio river by acid drainage water coming from neighboring subbituminous coal mines. Studies aimed at elucidating the cause of the intensive oxidation of the iron sulfide (pyrite) inclusions of those coals, led to the discovery of a bacterium, Thiobacillus ferrooxidans (Temple and Colmer, 1951), capable of acting as a catalyzer, accelerating the otherwise very slow chemical oxidation of iron sulfide to rates many orders of magnitude higher. However, it is now recognized that the biotechnology of microbial mining dates back to 1963, when the ability of this bacterium to solubilize copper from sulfide ores was ascertained (Razzell and Trussell, 1963). Much research has been carried out on biohydrometallurgy over these last 25 years and is still being actively conducted all over the world. The interdisciplinary nature of this young branch of science and technology is reflected by the variety of experts involved: microbiologists, mining engineers, hydrometallurgists, physico-chemists, mineralogists, solid-state physicists and biochemists. This intensive research effort has provided a solid background on the fundamentals of this technology, although many important issues have still to be solved, amongst which the enzymatic mechanisms controlling biocatalysis of mineral sulfides dissolution, the influence of bulk- and surface solid-state physics of metal sulfides on dissolution mechanisms, the interaction of the various strains composing natural microbial floras. Their elucidation should permit the rationalization of biohydrometallurgical techniques and the optimization of commercial processes. Biohydrometallurgy has already achieved satisfactory results: copper recovery from submarginal copper sulfide run-of-mine ores (i.e. assaying less than 0.3% Cu) by in-situ, dump and/or heap leaching is successfully practised in many countries and uranium recovery through bioleaching is competitive with other leaching processes.

Jan 1, 1987

By Louis M. Schlesinger, Michael J. Garska, Joel F. Hutwelker, James T. Jr. Tanner

A pilot plant was constructed and operated to investigate the column flotation of 20 x 200 mesh North Carolina phosphate ore, using high throughput, high solids operating conditions developed at the NCSU Minerals Research Laboratory. Flotation was performed at 45% solids in a 9.5 cm (3.75 in.) diameter by 2.26 m (7.4 ft.) tall column at throughputs of 19.1 t/hr/m2 (2.0 stph/ft2) and 31.7 t/hr/m2 (3.3 stph/ft2). Recoveries in excess of 98% of the phosphate value were obtained at the lower throughput -- while obtaining concentrate grades containing over 28% P205 (61.2% BPL) at that recovery. Recoveries of about 95% of the phosphate value were obtained at the higher throughput, while making a concentrate averaging 27.6% P205 (60.3% BPL). In addition, a better understanding of the variables governing the column flotation of coarse nonmetallic minerals was gained. Variables examined included superficial air velocity, throughput (superficial feed velocity), frother type, frother dosage, and bias rate.

Jan 1, 1993

By Young C. Kim

Introduction and Objective of This Paper Computerized open pit mine models* are more and more used today for feasi¬bility studies as well as for long range mine planning. In fact, using these models is becoming an enforced practice due to various reasons. One main reason is its capacity to evaluate several designs in a fraction of time required by manual effort. Another reason is the necessity to evaluate several. pit designs due to ever decreasing grade of the orebody and increasing financial risk due to smaller profitability margin. In spite of today's accepted use of computer models, very little guidelines are available which the average practitioner can follow either to choose or to build the type of model best suited for his need. Consequently, the objectives of this paper are: 1. To review the current state of the art in the computerized open pit mine models. 2. To provide some suggestions for model selection. 3. To share our experiences in developing a model for a highly irregular copper ore deposit (see Appendix).

Jan 1, 1977

The mining industry is one of the three pillars of the Namibian economic development, besides tourism and the fishing industry. Generating 20 % of the GDP and more than 50 % of the export income, half of this amount derives from the diamond mining industry. In 2008, the annual production of 2.2 mio carat achieved an income higher than 1.44 billion Namibian Dollars (more than 750 mio Euro). After the global recession in early 2009, which also caused a significant downcrease in production to only 0.93 mio Carat, the diamond mining industry easily restored itself and the production figures for 2010 are expected to be even higher than those achieved in 2008. Compared to other diamond producing countries, Namibia is mainly producing diamonds of highest quality (jewellery quality), with less than 10 % of the mined diamonds not falling into this category. This high quality stands also for the worldwide highest prize achieved per carat. With 370 $US per carat it is more than four times higher than that of the average South African stone. In 1908 the finding of the first diamonds in the Namib desert close to the coastal town of Lüderitz was reported by a Mr Stauch, railway inspector for the then German colonial railway company. This event immediately triggered a Diamond Rush and subsequently the set-up of the restricted diamond mining area ?Sperrgebiet? through the German colonial administration. In 1913, only five years after the first mining operations had started, the steadily increasing production allowed for more than 20 % of the diamond production worldwide. After the First World War, the new South African government concentrated all mining activities in one organization, CDM (Consolidated Diamond Mines of South West Africa) which in following decades conducted an extensive and detailed exploration of the whole Sperrgebiet and started numerous new diamond mining operations.

Jan 1, 2011

By John J. Dran

[This paper summarizes the more popular mineral valuation techniques being used by the dining industry, and attempts to demonstrate how they are Interrelated and where some are in error when compared to modern methods of financial analysis. The academic community and the larger and more sophisticated raining companies, have largely rejected the older valuation methods such as the, Hoskold and Morkill concepts and replaced them with "discounted cash flow" (DCF) techniques. The relevancy and usefulness of the older methods have been questioned primarily on the basis of their underlying assumptions that mining companies do not have numerous alternative investments and must use sinking funds deposited at market or ?safe" rates of return to recover the purchase price of mineral reserves. The ability to reinvest In numerous (often non-mining} alternative business ventures, the changing purchasing power of the dollar, corporate income and other taxes, depreciation and depletion allowances, and modern financial management practice, all mitigate against the continued use of the older valuation methods, especially for the larger mining companies. Snail mining companies and Individuals still use these methods largely out of habit and familiarity. This paper attempts to point out the weaknesses and strengths of the valuation methods In current use in the hope that these techniques may be better understood and [rcrn] appropriately applied.]

Jan 1, 1973

By Tianzu Yang, Weifeng Liu, Lin Chen, BOYI XIE, DUCHAO ZHANG, HUI XIAO

In this study, the oxygen-rich bath smelting process of copper dross was simulated using Factsage software. It was found that the two-step simulation results agreed better with the industrial data, especially in the speiss. Bismuth (Bi), lead (Pb), antimony (Sb), arsenic (As) and copper (Cu) contents in the speiss by two-step simulation differed from the industrial data by 0.6, 0.8, 2.6, 7.2 and 8.6 weight percent, respectively. The two-step simulation results indicate that the speiss partitioning of Sb, As and Cu increased from 60.1, 32.3 and 27.5 percent to 81.6, 67.8 and 47.2 percent, respectively, with the smelting temperature increasing from 1,050 to 1,250 °C, while the metal partitioning of Sb and Cu increased from 0 and 2.7 percent to 15.2 and 13.3 percent, respectively, with the separation temperature increasing from 400 to 700 °C.

By Martin B. Treuhaft

Expectations for coal in the early to mid-1970's prompted the government and industry to pursue research and development programs to increase underground and surface mining coal productivity and net coal recovery. Several programs concerned advanced surface mining methods for thin seam coal recovery. Three such programs, along with related areas of interest, are presented in this paper, namely: (1) extended depth augering for trench-strip applications; (2) high recovery auger heads for enhanced recovery; and (3) variable wall mining in low cover longwalls. Conceptual development is examined, prototype testing is discussed, and potential operations are considered.

Jan 1, 1983

By Jack M. Campbell

The regulatory process by which governmental authorities acknowledge and, in turn, permit the location, construction, and operation of large scale energy-related facilities has become extremely detailed in recent years. One example of the detail that is entailed in the regulatory process is the number of permits that must be acquired by operators prior to the construction and operation of energy-related facilities. It has been estimated, for example, that 75 permits are required prior to the opening of a new coal mine in Pennsylvania while 50 are required in Kentucky. From the perspective of facility owners and operators the regulatory process often appears overly complex and may be perceived as a constraint to the corporate decision making process. From the perspective of those responsible for administering regulations, the process is perceived as a mans by which public desires - pursuant to social objectives such as environmental protection and occupational safety - can be achieved. As a result of conflicting organizational interests, the clash between energy facility owners and operators and their regulators appears to be inevitable. Furthermore, the resolution of this conflict lies in the tradeoff between objectives and the costs of regulation. The balance of objectives and costs is a subject of the political process and not a topic of consideration in this paper. This paper is concerned with the actual administration of regulations, that is, the implementation of that which arises from the interplay of organizational interests. The paper assumes that environmental control laws will not likely be repealed, that regulations to implement the intent of these laws are here to stay and thus the paper seeks to assess how regulations are administered at various levels of government pursuant to objectives. The paper hypothesizes that the administration of objectives (or policy) has an impact on decision making which affects energy facility decision; making while recognizing the fact that regulatory policy cannot be totally divorced from administration, this paper proceeds

Jan 1, 1977

By Jorgen Elbrond

The calculation of open pit operations' capacities has been the subject of many studies using computer simulations. The common problems of simulation are that if one desires a realistic picture of an operation the programming work becomes long and expensive and that the program requires a large computer and long time to run. The method presented in this paper overcomes these problems by using a straightforward calculation procedure. It is based on the queuing theory's simple formula for waiting time in a closed circuit and uses a system of correction factors, which reflect the loading, travel, and dumping times' relative variabilities and which have been found by 1) mathematical analysis and 2) simulations of basic circuits. The method includes the main parameters of the operation: numbers, sizes and operational availabilities of trucks, shovels and dumping point, distribution of the production over shovels, trucks' loading, travel (loaded and empty) and dumping times as well as their variabilities, shift's composition. The procedure models: the average duration of a complete truck cycle during stationary and non-stationary periods during the shift as a function of the number of trucks in the circuit, the composition of the average 100% operated shift, the simultaneous probabilities of operationally available shovels and trucks and the distribution of shovels and trucks according to production and cycle times. The procedure can be programmed for a small computer and requires only short computing time, which makes extensive studies of various parameter combinations practical to carry out. The development of the method is an extension of previous work by Morgan and Peterson {1}, who by simulation established the relation between the match factor (which is the ratio between the sum of one loading time pr truck in the circuit and the complete net cycle time) and the shovel's efficiency, and by Hayes, Splaine and Whitaker {2}, who established this relation from a large number of observations in the Nchanga pit in Zambia. The present method establishes this relation by a straightforward calculation procedure. Theoretical solutions to some situations are found in the litterature on the queuing theory. The papers {3},{4} and {5} give solutions to situations, which fall outside those encountered in the shovel-trucks circuit. These solutions together with simulations of in-termediary situations have been used to establish an interpolation procedure for the correction factors to be applied to the waiting time formula in order to cover the situations encountered in practice.

Jan 1, 1977

By R. G. Reddy

Spent potliner is generated in the electrolytic process of reducing alumina to make aluminum metal using molten fluoride electrolytes. Spent potliner (SPL), obtained at the end of the pots life contains a small amount of cyanide and fluoride which present environmental problems. SPL became a listed hazardous waste under RCRA (K088) in July, 1990. One of the possible uses of spent potliner is as a substitute for Calcium Fluoride (CaF2) as a fluidizer in iron-and steel making and in the glass industry. A low viscosity and a low melting point are prime requirements for accomplishing the above. In the present study, viscosity measurements were performed. Effect of various additives, such as sand, limestone, dicalcium silicate dust, and MgO baghouse dust on the viscosity of SPL was studied. The results showed that with the addition of sand and limestone, very high fluidity of SPL melt can be obtained at significantly low temperatures. The results suggest that spent potliner mixed with additives could potentially be used as a substitute fluidizer.

Jan 1, 1999

By D. Duvris

The main objective of this work was to quantitatively investigate exhaust emission levels, as related to maintenance (service) intervals, during the operation of diesel-powered equipment at an underground bauxite mine in Greece. Such emissions depend on a great number of parameters, including the type (technology) and tuning of the engine, the type of work performed as related to the engine workload, suggested maintenance intervals, the altitude, the temperature and the humidity of the atmosphere of the underground mine, the properties of the fuel, the operator's training and experience level. Necessary ventilation quantities were calculated based on exhaust gas concentration measurements, site specific relationships between pollutants and adjusted air quality indices. Diagrams comparing necessary and recommended air flow for several equipment groups featuring two engine types and for different maintenance intervals are presented.

Jan 1, 1998

By Osvaldo A. Bascur

Standards and technology for bringing information to the desktop have greatly evolved in recent years. The benefits to be realized depend on how these new tools are embraced at the performer level. A key operating challenge is to ensure cooperative effort is geared towards the most efficient achievement of identified operating and corporate objectives. Presentation, application and database layers are emerging in successful client/server applications, the three-tier architecture.

Jan 1, 1996

By Charles B. Manula

This paper describes the development of a mathematical model for simulating the behavior of a longwall coal production system. The longwall simulator is a design simulator incorporating both deterministic and stochastic methods to calculate: (a) the size and density of support; (b) the cutting force, power requirements and haulage speed for the loader-shearer; (c) the conveyor size, speed and power requirements; and (d) delay generation at head and tail-gates and the longwall face.

Jan 1, 1978

By David Kress

Grinding mills, both autogenous and ball can be powered by several basic means. The three methods used today are girth gear drives, gearless drives and trunnion coupled reducers. This paper will focus on the first of these methods -girth gear drives. The girth gear drive has been used on thousands of mills which continue to operate successfully. These drives are noted for their simplicity and low cost. In the past, the horsepower capacity of girth gears has been slow to keep up with the horsepower increase required by the mill builders, particularly since the advent of the SAG mill. Gear manufacturers had capacity for 2000 HP mills in the 1950's, 5000 HP in the 1960's and 6500 horsepower in the 1970's. The 70's and 80's brought dual pinion girth gear drives which allowed mill sizes beyond 10,000 horsepower. Gear manufactures who could not keep up with the pace of the horsepower demands and the quality and reliability demanded by the mill builders and users have fallen by the wayside.

Jan 1, 1991