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By G. Pan

A geostatistical approach is proposed for the design of infill drilling programs. The method is consisted of three major steps: developing geological favorability models, delineating mineralization and ore envelopes, and classifying reserves or resources. Geological modeling aims at developing favorable geological zones in which drilling is designed. Modeling mineralization and ore envelopes establishes criteria on potential blocks to be drilled. Top target blocks should be those included within ore envelopes. The framework of resource categories includes five types: probable reserves, indicated reserves, indicated resources, possible resources, and barren. Indicated reserves or resources are the top priority to be drilled for the definition of minable reserves. Possible resources may be considered as targets for further exploration. The algorithms involved in the analysis include indicator favorablity analysis, ordinary kriging, and indicator kriging. A case study presented here involves a gold deposit of Carlin type. The deposit was delineated by a sparse drilling program with 230 feet of average spacing. The infill drilling program designed by the new method suggests a significant reduction on the number of holes from a regular-grid infill drilling pattern.

Jan 1, 1995

By O. Alvarez-Campos

Two porphyry copper orebodies, the North and Central MM orebodies, have been found through regional and structural geologic works, about 5 Km south of Chuquicamata, under a gravel bed of approximately 100 m and in the west side of the West Fissure. The mineralization is emplaced in a coarse granodioritic porphyry, predominantly with sericitic alteration. In the North MM ore-body, with 200 million metric tons of 1.0% Cu, the mineralization is mainly chalcopyrite, bornite, digenite and molibdenite. In the central MM orebody, with 700 million metric tons of 1.3% Cu, there are large veins of enargite, chalcocite and bornite, the last one increasing in depth, separated by chalcopyrite and pyrite zones; in these veins there are interesting gold and silver values. Both orebodies have an upper enrichment of chalcocite and covellite, with pyrite envelope. According with these characteristics, the MM orebodies could he the upper part, with sericitic alteration, of the Chuquicamata porphyry copper system, displaced by the West Fissure system movements, but we couldn't eliminate the possibility that MM can be a new orebody, different of Chuquicamata.

Jan 1, 1993

By Joe B. Rosenbaum

Waste solutions from sea water desalination processes are enriched in minerals by a factor of two or three. This suggests that extraction of selected mineral components from the concentrated brine might help pay desalination costs. The possible recovery of gold has received particular mention. Sonstadt, in 1872, reported the gold content of sea water as 65,000 micrograms per cubic meter, or 65,000 parts per trillion. At $35 an ounce, this is equivalent to $0.065 per ton of sea water. Fritz Haber, however, after his abortive venture to restore Post War I Germany to economic health by recovering gold from the sea, concluded the gold content was 4 micrograms per cubic meter. Haber's analysis is equivalent to 0.0004 cent per ton. In the past 10 years, investigators using advanced analytical techniques reported from 4 to 27 micrograms per cubic meter. Our brief experiments to determine a threshhold value for the gold in sea water employed solvent extraction for initial concentration, evaporation of the gold-loaded organic for further concentration, and atomic absorption analysis of the gold in the concentrated organic. Radioactive gold was used as a tracer for monitoring the gold through the concentration and analytical steps. Our method established that sea water contains about 11 parts gold per trillion parts sea water, or 0.001 cent worth per ton. This agrees closely with results of recent studies by other investigators employing ion exchange resins and neutron activation techniques.

Jan 1, 1969

By Noris Del Be1 Belluz

Drilling underground in the Grasberg dewatering drifts has routinely hit water aquifers with high flow rates and pressures. Two types of holes are used. Pilot holes probe ahead of the tunnel development to intersect aquifers ahead of the face. And dewatering holes dewater rock formations that will drain water from the Grasberg pit and allow tunnel development to proceed safely. Recently, static pressures of >8.3 MPa (> 1,200 psi) have been recorded with flows from a 100 mm (4 in.) HQ core hole measured at 5,700 L/min (1,500 gpm). The waterflows can be slightly acidic, necessitating the use of stainless-steel collar gear to resist corrosion. These rates were anticipated and contingencies were planned early on to deal with these conditions. PT Freeport Indonesia (PTFI) established procedures to maintain the safety of the drill crews, to enable coring of the rock, and to maintain the safety of the miners driving the drifts. The collar gear controls the waterflows because these drill holes are a vital source of water for the concentrator.

Jan 1, 1998

By Jay F. Colinet

Coal workers’ pneumoconiosis (CWP), commonly known as black lung, is caused by the inhalation of respirable coal mine dust and is a disabling and potentially fatal lung disease with no cure. Historically, CWP has taken a tremendous human and financial toll on the U.S. coal mining industry. Recent health surveillance data indicate that CWP continues to occur at elevated levels. Respirable coal dust exposure must be controlled to prevent the development of CWP. The Pittsburgh Mining Research Division of the U.S. National Institute for Occupational Safety and Health (NIOSH) conducts laboratory and mine-site research to identify control technologies that can be used to successfully reduce respirable dust levels. Various technologies, using multiple methods of control, can be applied to reduce dust levels. An overview of CWP’s impact and a general methodology for controlling respirable dust in underground coal mines are discussed in this paper.

By C. Flores, L. G. Twidwell, T. S. Jordan

It is well known that manguniferous silver ores containing manganese intimate) associated with silver are not amenable to conventional extraction methods. The segregation process has been applied primarily to the recovery of copper from oxidized and oxide-sulfide ores. A new alternative process, consisting of segregation roasting followed by flotation to recover the silver from refractory manganiferous silver ores, was studied using a 23-factorial experimental design. Laboratory investigations were conducted on a manganiferous silver ore analyzing 0.02% copper, 0.09% lead, 0.33% zinc, 12.55% manganese and 187 g/t silver. The investigation was designed to study the effects of the addition of salts, coke and copper (11) oxide on silver recovery. The results indicated that 79.3% of the silver can be recovered in the absence of copper oxide and 88.4% of the silver can be recovered with a copper oxide content of 1.5% at 750°C, 2% salt (NaCI). 1 % coke and 30 min of roasting. It was concluded that the addition of copper oxide improves silver recovery.

Jan 1, 1996

By R. J. Snoby, J. K. Alderman

Although once fairly common as a method of coal preparation in the United States, dry cleaning has virtually disappeared. Low-rank coals used for power generation in the western U.S. are suited for dry cleaning because water has limited availability in the American west. Surface moisture added through wet cleaning offsets energy improvement achieved from mineral matter reduction. Information will be presented on the commercial application of dry cleaning in North America, the historic development and current status of the technology, and the introduction of modern processing theory and control technology to the design of dry cleaning equipment and plants.

Jan 1, 2001

By H. G. Linge

Pyrrhotite (FeS1+x ,0<x<0.15) is an iron sulfide which is considered to be a pest in carbon-in-pulp/ leach (CIP/L) gold processing [l].The perceived influence of pyrrhotite on gold processing by CIP/L is a competing consumption of 02 and CN­as the pyrrhotite dissolves by oxidation [1,2]. The few studies of the oxidation chemistry, kinetics and mechanism of the oxidation ofpyrrhotite are reviewed in detail elsewhere [3].There is broad agreement that the surface of pyrrhotite is very rapidly oxidized to form a thin (e.g. 10 nm) ferric hydroxy-oxide layer which overlays an iron-deficient sulfide lattice covering the original pyrrhotite. The reaction can be summarized thus:

Jan 1, 1995

By F. L. Pirkle, W. C. Bagby

The International Mineral Valuation (IMVAL) Committee, founded in 2012, develops strategies for conducting mineral valuations. These strategies have been developed into a mineral asset valuation template called the International Mineral Property Valuation Standards Template and is part of IMVAL's work to establish consistent international standards for mineral property valuation and reporting. This template is a living document that is updated from time to time and is based on three core values or pillars (Fundamental Principles): Competence, Materiality, and Transparency. Objectivity, Independence, and Reasonableness may be applied as required by national codes or standards. The Template harmonizes international standards for valuation of mineral assets as real property and represents a consensus of current good practices. It is not a stand-alone reporting code and does not supersede existing national reporting standards. The Template deals with mineral-property valuation as distinct from mineral-project evaluation. INTRODUCTION In his 1989 book, “The New Realities”, Peter F. Drucker, Clark Professor of Social Science at Claremont Graduate School, California, stated: “Information is data endowed with relevance and purpose. Converting data into information thus requires knowledge. And knowledge, by definition, is specialized.” (p. 209) The discipline of mineral valuation is knowledge-based and requires a mineral valuer to collect, analyze, and interpret data that are material to a mineral valuation assignment. In so doing, the valuer turns the data into information (data come first, followed by information as determined by the mineral valuer) for use by the client (from whom the valuer obtained the mineral valuation assignment) and other intended users. The valuer uses his or her experience and education (each valuer’s knowledge base) supported by a foundation built upon competency, materiality, and transparency, the three pillars of mineral valuation (“minerals valuation”, “mineral-property valuation”). The International Mineral Valuation Standards Template (“IMVAL Template”, IMVAL”, “Template”), third edition dated May 2018, defines mineral valuation as: “The estimation of the Value of a Mineral Property in money or monetary equivalent. The word ‘valuation’ can be used to refer to the estimated value (the Valuation conclusion) or to refer to the preparation of the estimated Value (the act of valuing).” (p. 14) Furthermore, the IMVAL Template clearly separates valuation from evaluation: “The Template deals with Valuation, which is distinct from Evaluation. The distinction inherent in these defined terms is that Valuation addresses the estimation of value of a Mineral Property, whereas Evaluation addresses the broader assessment of a Mineral Property for an investment decision.” (p. 2)

Jan 1, 2019

By Ratnakar Singh, Raj Kishore, Kisor Kumar Sahu, Ranjeet Kumar Singh, Ganesh Chalavadi

The Falcon concentrator is capable of separating minerals in fine size classes based on their differential density. Separation of mineral particles depends upon the fluid flow characteristics and relative movement of particles in a fluid. In the present study, a fluid flow characteristic inside the Falcon concentrator was established through experimentation and modeling. The Falcon concentrator has two fluid entry points: (a) Fluid entering through gravity assisted feeding system and (b) Fluid entering through the fluidized hole on the concentrator wall. In order to identify the role of fluid entering the concentrator, a tracer was injected into the system. As per the tracer based experimentation, it was established that fluid entering through the gravity based feeding system is responsible for thin flowing film formation in the stratification zone where particles are stratified based on their relative density. The momentum balance and continuity equations were simplified for a high centrifugal force field, and the fluid velocity profile was estimated inside the thin flowing film. Estimated fluid flow profiles will help to simulate the particle trajectories inside the Falcon concentrator. The influence of rotational speed, fluid flow rate, and cone angle on the fluid velocity profile were investigated. Fluid thickness over the concentrator wall is also estimated, and it is typically of the order of ~150–200 μm.

By Todd Hollingsworth

The Boddington gold mine is located near Perth in Western Australia in the Saddleback Greenstone Belt, a fault-bounded sliver of Archaean volcanic and shallow level intrusive rocks, surrounded by granitic and gneissic rocks. The mine began operations in 1987, producing about 7.7 t/a (250,000 oz/year) until mining ceased in 2001. Built on the footprint of the original mine, the Boddington gold mine expansion project involved opencut mining from two large pits. Expected gold production is around 31 t/a (1 million oz/year) for the first five years. It will be the largest gold mine in Australia. The mine has proven and probable reserves of more than 622 kt (20 million oz) of gold and has an expected life of more than 24 years. The mine is currently solely owned by Newmont Gold Corp., the world?s second-largest gold mining company, employing around 28,000 people worldwide. The conveyor and belt feeder contract for the Boddington gold mine expansion project was awarded by Aker Kvaerner Clough Murray Roberts (AKCMR) to FLSmidth Conveyor Engineering Inc. in August 2006. The contract involved the design and manufacture of 15 conveyors and 17 belt feeders with belt widths ranging from 450 mm to 2.4 m (18 in. to 96 in.) and conveyor lengths from 16 m to 2,172 m (52 ft to 7,125 ft). The total motor power added up to more than 16,700 kW (22,400 hp). The total length of all belting was almost 11.5 km (7.1 miles), and the total fabricated steel weight was approximately 3.7 kt (4,100 st).

Jan 1, 2010

By Wi11iam I. Rau

In the recent past, there have been numerous projections of the capital requirements for additional mine and processing capacities required to meet projected non-Communist World demand for minerals during the next 15 years. A consensus judgment would place this currently at $14 billion per year, with the largest expenditures required for increases in aluminum and copper production. Until the early 1960&apos;s, internally-generated funds were used to finance nearly all of the large mining companies&apos; capital requirements. Since that time, however, the enormous rise in capital costs per ton of capacity, accompanied by a relative stagnation in the financial condition of many of the major mining companies, have caused the industry to begin to rely on external sources for financing expansion, most notably, project financing from commercial banks and institutional lenders. Seven years ago, it was estimated that, in the five-year period 1972-1976,75% of the total capital requirements of $10 billion per year would come from internally-generated funds, with the balance to be provided by external sources. l There is little doubt that, in the coming decade, the percentage provided by external sources will increase. There should be little difficulty in attracting the necessary investment within the U.S., particularly in view of the expected continuation of companies in diverse industries seeking mineral investment opportunities. The more serious question lies in the availability of internal and external sources of funds for the expansion of mine and smelting capacity in the developing countries. Recently, R. F. Mikesell projected an average annual investment of $4.7 billion (in 1977 prices) over the 1977-1990 period would be required from foreign sources to expand metal producing capacity in developing countries. Mikesell concluded that external financing of mining projects in the developing world has averaged less than $1 billion per year over the past five years, thereby requiring more than a quadru1ling of this financing over the next decade.

Jan 1, 1978

By Ewan Wingate, Ranjit Prasad, Yanjun Liu

The use of phosphorus by mankind is long established. From use in agriculture, foods, high tech electronics, and more recently in EV battery cathode production, one cannot escape its impact on today’s society. This paper will review and describe the circular journey of phosphorus through its value chain from the mining operation of phosphate ore through beneficiation into downstream chemicals production and finally into the EV battery cathode production space. This will include a review of phosphoric acid production from phosphate concentrate using wet process route and thermal route. The wet process route discussed will be via dissolution of phosphate concentrate by sulphuric acid. The thermal route will discuss thermal decomposition of phosphate concentrate using submerged arc furnace to produce yellow phosphorus followed by its combustion to produce phosphorus pentoxide and subsequent hydration to produce phosphoric acid. It will also discuss briefly other phosphate derivatives for specialty chemicals and recovery of phosphorus units from wastewater treatment plants, sewage sludge and incinerator ash. Finally, the paper will discuss the use of phosphorus in EV batteries in the form LFP cathode materials and its production. It will also briefly discuss the LFP battery recycle.

Sep 11, 2023

By Han Zhao, FENGLIANG WU, Tong Wang

Calibrating an entire mine ventilation network model from survey data has long been considered a challenging and sometimes impractical task. This paper proposes a solution to this issue with the development of a quadratic programming optimization model. The optimization model takes the minimum modification of input resistances as the objective function, uses the mesh pressure equations as equality constraints, and incorporates the lower limits of airway resistances as inequality constraints. A two-step method is developed to solve the model, which includes finding an initial feasible solution and iteratively solving the final solution using the active set method. A computer program has been developed to implement the optimization model. To demonstrate its practicality, a study case using a 35-branch ventilation network is presented, which indicates that the solution process converges after only 57 iterations, a significant improvement over the times of trial and error, which could reach 3.4 × 1010 for the worst-case scenario. Additionally, it is shown that considering only the equality constraints results in negative resistances, while incorporating the lower limits of resistance ensures that the corrected resistances are within a reasonable range. Using the resistance corrected by the optimal model to simulate the ventilation system via traditional methods generates quantities and fan pressures that perfectly match the measured values, eliminating the tedious process of manually adjusting airway resistances repeatedly.

Jan 13, 2024

By B. M. Eiter, J. Hrica, D. R. Willmer

"Mineworkers are routinely tasked with making critically important decisions about whether or not a hazard presents an imminent danger. Researchers from the U.S. National Institute for Occupational Safety and Health collected formative data to investigate mine safety professional perspectives on workplace examinations, which revealed a potential gap in how mineworkers are assessing risk. During interviews, participants revealed not having a systematic methodology for mineworkers to use to determine if a hazard is considered imminent danger. In this paper, we identify and describe three distinct categories of imminent danger complexity and discuss potential steps that could lead to improved identification of imminent danger situations. Finally, we identify potential practices to incorporate into risk management efforts, including feedback, communication and specialized training, to increase awareness of imminent danger situations. IntroductionIn recent years, the metal and nonmetal mining sector, as categorized by the U.S. Mine Safety and Health Administration (MSHA), experienced an increase in the number of fatalities occurring at mine sites. From 2013 to 2015, 69 mineworkers were fatally injured, twice the number of fatalities in each of the previous two years (MSHA, 2015a). As a way to address this increase, MSHA issued its P15- IV-01 program policy letter, suggesting that “miners would benefit from rigorous workplace examinations conducted by experienced and trained examiners” (MSHA, 2015b). The goal of these examinations is to find hazards in the field and mitigate them before they cause injury or death to mineworkers. While it is important to identify all hazards in the workplace, it is critically important to identify those hazards that are considered imminent danger because they require an immediate response to avoid a severe or even fatal injury."

Jan 9, 2018

By Michel Dagbert

In the exploitation of porphyry-type deposits, the quality of the ore is mostly defined according to its grade. Besides the simplest distinction, ore-waste, several grade categories may exist and they correspond to the different ways in which the ore is further processed. At the time of mining the selection of the different categories is done from extensive information available from blast holes. But planning has to be done before this information is available and it is necessary for the geologist to forecast, from exploration and development data alone, the possible outcome of the selection done later on a block, a level, or the whole deposit and ultimately predict the ore reserves and value of the deposit. A good statement of this problem has been presented at the 1976 AIME annual meeting by Williamson and Hueller (1976). They have shown that, if the cut-off values are directly applied to the estimated grade of blocks, a gross overestimation of the recovered tonnage of ore (14%) will occur. This problem, now termed "the vanishing tons problem" (DaVid, 1977) seems to be common in many open-pit operations and it has been explained several times (DaVid, 1972; Huijbregts, 1975). In order to solve it l.Jilliamson and Mueller proposed a solution based on compiling masses and masses of blast hole data available from mined-out portions of the deposit. They derived empirical correction factors which provide for every block, given its estimated grade, the expected tonnage and average -grade of each category of material within that block. The purpose of our work is to repeat the same exercise but ignoring the blast holes data i.e. we want to derive the correction factors from the only DOH data. Doing this, we are more in the real conditions where the valuation of the mine and are reserve analysis has to be made before production actually starts. Two possible ways to achieve this goal will be investigated and the emphasis will be on recently

Jan 1, 1977

By M. Slatter

The need for anti-corrosion coatings has existed for many years in the ground support industry, but the application requirements have made coating selection limited. Varying groundwater and chemical conditions continually challenge long term coating performance. Traditionally the industry coating preference has been hot-dip galvanizing due to its performance characteristics in highly corrosive environments and low cost nature. However, the galvanized coating has application limitations. This paper highlights some of these limitations and provides selection criteria for a new organic coating developed for one such difficult application, DSI?s Omega BoltPTM Pwhich is an expandable ground support. [ ]

Jan 1, 2009

By James R. Norris, Thomas A. Conto, Gary R. Walter

For at least five decades, a plume containing acidic metal-bearing water has been moving through the shallow alluvial aquifer along Pinal Creek in the Globe-Miami area. Two chemical facies of water are distinguished in the alluvial aquifer: (1) a metal-rich acidic plume with gram per liter concentrations of metals (primarily iron) and pH values between 3 and 5 and (2) neutralized water with a pH greater than 5, low concentrations of metals, and high concentrations of sulfate and manganese. Historically, the acid plume has moved through the aquifer at an average velocity of 0.6 m/day, ten times slower than the average pore velocity of groundwater in the aquifer calculated using the Darcy equation. The rate of migration of the metal-rich plume is retarded by pH-dependent chemical reactions between acid water and the aquifer matrix. As acid water is neutralized by reaction with calcite, rising pH conditions in- crease the oxidation rate of iron and decrease its solubility resulting in the precipitation of ferric hydroxides. The formation of ferric hydroxides is a proton releasing reaction which main- tains acidic conditions. The acidit of the plume and the neutralization capacity of tKe aquifer are best assessed in terms of the iron content of the water and not the hydrogen ion activity computed from pH measurements. The parameters controlling plume migration are: (1) the calcite content of the aquifer (2) the iron acidity of plume water, and (3) the rates of acid neutralization and ferrous iron oxidation. A numerical solute transport and reaction model based on the concept of iron acidity effectively simulates the historical development of acidic conditions, predicts the behavior of the plume, and was used as a management tool to identify the most efficient and cost effective remedial strategy.

Jan 1, 1991

By O. M. S. Rodrigues

The kaolinite presence in bauxite ores increases caustic soda consumption during the digestion step in the Bayer process. Depending on the kaolinite content, the utilization of the ore in the Bayer process may be unfeasible. This investigation addressed the variables involved in kaolinite flotation through microflotation experiments in a Hallimond tube and zeta potential determinations. The tests were performed with a pure sample of kaolinite (96%). Five collectors were tested: Duomeen T (DT), cetyl pyridinium chloride (CPC), cetyltrimethylammonium bromide (CTAB), dodecylamine (DDA) and Flotigam EDA (EDA). Four of them performed well as collectors, at a concentration of 1x10-4 mol/L: CPC, CTAB, DDA and EDA. The kaolinite isoelectric point (IEP) was determined at pH = 4.6. The IEP was shifted towards higher pH values in the collectors? presence, indicating specific adsorption onto the mineral surface.

Jan 1, 2011

By J. S. Rapp

This report is based on existing reports and recently gathered field data. It discusses mineral resource potential of Tertiary playas in the Fort Irwin region. An estimated 1.3 million tons of measured salt "reserves", and 20 million tons of indicated salt resources, have been identified north of the fort. Other indicated resources include 300,000 tons of celestite, 800,000 tons of gypsum, and 10 million tons of selenite. Zeolitic tuff was mined south of Fort Irwin from 1978 to 1984, and unexplored occurrences are widespread. Calcium-bentonite is mined near Barstow, and more may exist, including valuable sodium-and lithium-based bentonites.

Jan 1, 1992