Search Documents

By Kenneth L. Maloney

Ten small and intermediate-sized [11 GJ/hr to 264 GJ/hr (10,000 lb/hr steam to 250,000 lb/hr steam)] coal-fired boilers in the upper Midwest have each been tested on both a bituminous eastern coal and a subbituminous western coal. The purpose of this study was to determine the feasibility of substituting western subbituminous coal for eastern bituminous coal as a means of reducing the SO x emissions from this class of boiler and to demonstrate the feasibility of greatly expanded western coal utilization as a means of reducing the use of oil and gas. The scope of this study was such that the representative boiler types were tested on both eastern and western coal for a period of time sufficient to completely characterize their individual emission and operational characteristics.

Jan 1, 1977

By A. Pincomb

After determining minable acreage, tons are calculated by multiplying minable acreage by average thickness and by a volume-tonnage conversion factor. Converting from tons in the ground to tons sold across the scale takes fines and internally used and wasted stone into consideration, resulting in minimum losses of about 10% for limestone and 15% for sand and gravel. A high degree of certainty about thickness, lateral continuity and geologic character defines proven reserves. Assuming continuity of these characteristics defines probable reserves. By using tpa estimations and annual tonnage requirements, the life of a deposit can be quantified. The decision can then be made regarding the necessity of securing more acreage. Some landowners choose to multiply aggregate price, operating income, or a royalty rate by tons to arrive at a value for their reserves. In doing so they probably overstate the value of their land.

Jan 1, 2003

By Todd Grounds, William R. Reed, VASU GANGRADE, Michael Shahan, Garron Ross, Kunal Singh

Roof bolter canopy air curtains (CACs) are gaining acceptance as a respirable dust control device that can provide roof bolter operators with protection from overexposure to respirable coal mine dust. Both lab and field studies on the effectiveness of roof bolter CACs have been published. Field studies have shown the effectiveness to be variable. However, in all previous field studies, none has been conducted when the roof bolting machine operates downwind of the continuous miner (CM)—a scenario for which the CAC was designed to provide respirable dust control. This study, performed by researchers from the National Institute for Occupational Safety and Health (NIOSH), was conducted to test a CAC on a roof bolter machine operating downwind of the CM. The results of testing demonstrated that the roof bolter CAC can effectively provide respirable dust protection for roof bolter operators with dust control efficiencies ranging from 11 to 40%.

Oct 14, 2020

By J. Evans

INTRODUCTION Section 209(b) of the Federal Land Policy And Management Act of 1976 (FLPMA-43 U.S.C. 1719 b) authorizes the Secretary of the Interior to convey mineral interests owned by the United States where the surface is or will be in non-Federal ownership. The objective is to allow consolidation of surface and subsurface (mineral) ownership. Certain major conditions must prevail for a conveyance to occur. These are: 1) There are no known mineral values (KMV) or 2) Where the mineral reservation interferes with or precludes appropriate non-mineral surface development and that non-mineral development is a more beneficial use of the land than the mineral development. Remember that allegation, hypothesis or speculation that the conditions could or may exist in the future will not be a sufficient basis for conveyance. Convincing factual evidence for an applicant’s case for mineral conveyance must be made in order to achieve that conveyance. See 43 CFR 2720 0-1 to 0-3, and 0-6. CONCEPT OF KNOWN MINERAL VALUES Known mineral values means mineral rights in lands containing geologic formations that are valuable in the monetary sense for exploring, developing, or producing natural mineral deposits. The presence of such mineral deposits with potential for mineral development may be known because of previous exploration, or may be inferred based on geologic information (43-CFR 2720.0-5(b).

Jan 1, 2007

By J. Lorengo, C. H. Bucknam

"Standardization of the Inductively Coupled Plasma Mass Spectrometry (ICPMS) method for gold in cyanide solutions was undertaken to provide a more sensitive method to quantify the gold content than the atomic absorption method standardized in 1994 (E1600). The gold concentration range covered is from 0.001 mg/L Au - 0.3 mg/L Au (0.00005 toz/t Au – 0.009 toz/t Au). Interlaboratory testing was carried out with the assistance of the American Society of Testing and Materials (ASTM) International on two committees to determine the within laboratory and between laboratory reproducibility. Three barren solutions from metallurgical operations were measured in triplicate to satisfy statistical requirements for Committee E1 on Analytical Chemistry of Metals, Ores and Related Materials. A synthetically prepared matrix representing the metallurgical processing solutions was used to prepare Youden pairs to satisfy the requirements of Committee D19 on Water. Results of the standardization program are presented. INTRODUCTION Analysis of process solutions for gold concentration requires accurate and sensitive analytical methods in order to manage process control and metallurgical accounting. Flame atomic absorption spectrophotometry (FAAS) has been the work horse of the assay lab for this duty for decades. In 1994 the FAAS standard method was approved by the American Society for Testing and Materials (ASTM) (1). Six process solutions were collected and preserved by measuring the pH and adjusting to greater than pH 10, if necessary. Duplicate solutions were provided to eight laboratories in random order for analysis by FAAS covering the gold concentration range of 0.19 µg/mL (0.006 toz/t.) to 10.7 µg/mL (0.312 toz/t). A high precision method was used, which involved bracketing the sample with the higher and lower standards nearest to its concentration repeating readings three times and averaging the results. The optimum precision for the FAAS gold method was found to be at the 1.00 µg/mL (0.029 toz/t) and lower scope limit 0.3 µg/mL (0.009 toz/t) gold concentration. Since tailings solutions typically have concentrations below the lower scope limit, use of ICPMS was developed at Newmont USA Limited (Newmont) to assay the lower range solutions."

Jan 1, 2016

Shallow ore deposits are mined by surface methods but a depth is reached in the case of most deposits after which underground methods are applied for the extraction of the remaining ore. The determination of this depth and its analysis is the subject of this paper. In order to determine transition depth from open-pit to underground mining on the basis of the allowable and economically feasible overall stripping ratios, an economic-mathematical equation is first introduced. Using the achieved equation and an analytical procedure on a particular two-dimensional hypothetical tabulate deposit, an effective formula is then established. The formula introduced here, together with the procedure adopted, could be used in all similar mining situations by the mining design engineer.

Jan 1, 2010

By George J. Hartman

The Fort Cady in situ borate-mining project involves recovering boron from a deposit more than 400 m (1,300 ft) below the surface. The resource recovery method is a new in situ mining technology that uses weak acid solution injected directly into the ore body. As the acid contacts the calcium-based ore (primarily natural colemanite), the contained borate values are digested as boric acid. This boric acid solution is then pumped to the surface by submersible pumps. A series of chemical reactions and precipitations are performed that result in the production of calcium borate. The borate values are then recovered as a finely divided solid white powder. The refined product is sold under the trade name Cadycal 100. The Fort Cady in situ borate-mining project is located about halfway between Los Angeles, CA and Las Vegas, NV in the Mohave Desert.

Jan 1, 1996

By David L. Giles

The Lime Creek* ore body in northwestern British Columbia is one of the few commercial primary stockwork-type molybdenite deposits in North America. Others include the Climax, Urad-Henderson, Questa, and Endako ore bodies. They are mined on a low grade-high tonnage basis, and are open pit operations except for Climax and Urad-Henderson. Much recent geochemical research on both porphyry copper and stockwork MoS2 deposits has been concerned with dating of micas related to the mineralization and associated igneous rocks. The results appear to show that mineralization and the predominant magmatic events of the deposit are indistinguishable in age (1-5), except where dating has been in sufficient detail to resolve the analytical overlap (6). At Lime Creek, geologic information shows that the Main granodiorite, the major intrusive and dominant host rock for MoS2 mineralization, was emplaced and had solidified sometime prior to the introduction of MoS2. The first MoS2 episode is intimately related to localized bodies of kalialaskite which clearly intrude the older stock. K-Ar dating was undertaken to clarify the age relations between Lime Creek plutonism and the apparently younger hydrothermal event that began with kalialaskite.

Jan 1, 1975

By Daniel Hodouin, Claude Bazin, Sami Makni

A method is proposed to perform on-line data adjustment and inference of unmeasured variables, using measured flowrates and on-stream assays in mineral processing plants. The algorithm minimizes a weighted sum of squared residuals of the measured variables and squared species imbalances around the flowsheet nodes. The method is based on a trade-off between the material transient accumulation, evaluated by the imbalances, and the data inaccuracies, evaluated by the residuals (i.e. the adjustments brought to the measured values). A recursive algorithm is developed for on-line implementation of the method. It is a real-time extension of the hierarchical method for balancing steady-state data for bilinear mass conservation constraints. An illustration for a simulated flotation circuit is provided.

Jan 1, 1995

By D. A. Huggins

Column flotation is finding increasing use in the flotation of copper, molybdenum and other heavy metals and coal. Columns have proven operational, cost and metallurgical advantages which caused us to investigate their use in the proposed Escondida flowsheet. A comparative pilot plant test with 35 tons of ore showed that one column can replace three stages of cleaning and result in a significantly higher concentrate grade with no loss in recovery.

Jan 1, 1987

By C. W. Schultz

Earlier publications from The University of Alabama have indicated that column flotation performance is improved when operating at low pulp levels and when the feed is directed into the froth phase. To validate these early observations a series of tests were performed in which the position of the feed entry to the column and the pulp-froth interface were systematically varied. The optimum grade-recovery relationship was achieved with high feed entry (WA) of column height) and very low pulp levels (<10% of column height). The position of the pulp-froth interface appears to be the more critical variable. When operating in this mode (1. e. at low pulp levels) column flotation becomes. in reality. a froth separation process.

Jan 1, 1991

By Jiachen Wang, Nan Wang, Yang Li

The energy structure and consumption ratio in China determine the practical demand for the collaborative mining of coal and co-associated resources. The multi-layer mining of coal, uranium, coalbed methane, and oil and gas co-associated resources, represented by the Ordos Basin, Junggar Basin, and Tarim Basin, faces numerous challenges. Additionally, coal has been found to coexist with various mineral resources in 33 coal-bearing basins worldwide. The scientific issues related to the multi-layer development of coal related co-associated resources urgently need to be addressed. This paper discusses the unique challenges and potential solutions in the multi-layer development of coal-related co-associated resources. The challenges include large extraction space, high mining intensity, intense overburden movement, rapid surface subsidence, and severe overburden damage due to repeated mining disturbances. Proposed solutions include the establishment of a correlation mechanism between multi-layer mining and the carrying capacity of the overburden environment, analysis of the impact characteristics of multiple field couplings, and exploration of their superposition evolution laws. The paper also proposes the development of a comprehensive evaluation and prediction system for overburden environmental capacity loss, a global sensitivity analysis model for overburden environmental capacity, and an intelligent identification and early warning system based on multi-source information fusion. These solutions aim to achieve scientific and precise mining with minimal overburden environmental capacity loss. And the multi-layer development of coal-related co-associated resources is a complex task that requires a multidisciplinary approach and innovative solutions, and further research is needed to validate these strategies and explore new methods and technologies for efficient and sustainable extraction.

Jun 25, 2024

By T. BACHMANN, G. SHAPLAND, E. Amini, N. BEATON, M. BECERRA

In this study, several methodologies to manage low grade and often competent portion of the ore have been proposed and tested in lab, pilot and operational scales. Relevant to this subject, the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE) has developed Grade Engineering® (GE) concept to modify feed streams by rejecting the low grade and possibly hard components in the stream at the early stages of a value chain. Application of GE requires to understand the impact of the process on the value chain as they are value modifiers on in situ opportunities. Traditional modelling approaches and tools do not have the ability to run the analysis in a block model scale with high fidelity in an integrated value chain. Integrated Extraction Simulator (IES) in conjunction with sophisticated analytical tools such as a neural network (NN) was used to develop and reconcile a fully integrated value chain. The value chain model makes it possible to run all available blocks in the Geomet block model, which could be several millions, under possible scenarios for Grade Engineering for economic evaluation analysis and mine planning.

Sep 16, 2020

By F. A. Renninger

The terms environment and environmental control, when used in today&apos;s context, generally imply to the average individual, something to do with pollution and pollution control. These latter terms, likewise, impart visions of fouled air and dirty water attributable largely to the industrial segment of American society. We have been conditioned, by various means, over the past ten years to equate environ¬mental control with pollution control. We have been trained to think of industrial environmental control programs as efforts conceived only to comply with one or more of the recently imposed pollution control regulations. Almost automatically we; approach consideration of environmental control with a degree of pessimism that is we assume that pollution prompted the control program. It is the purpose of this discussion to demonstrate that environmental control. at least as it exists and has existed within the crushed stone industry, involves far more than simply control or reduction of air and water pollution. It involves a dedication to the enhancement of each of the several "mini-environments" which together comprise the total world surrounding any given crushed stone operation. Environmental control, exercised properly, is an optimistic, constructive, forward-looking, enhancing type of activity. It is a function which has been, and should continue to be, willingly and expectantly undertaken by informed management personnel. In short, environmental control. is an activity from which both industry and society can and should benefit.

Jan 1, 1972

By Valerie (Wollet) Rebar

Successful execution of fast-track projects is an arduous task at best. Effective and organized management, a comprehensive technical design with an independent check-and-balance system, and optimal schedule components all play major roles in project success, regardless of the required timeline. However, a fast-track schedule intensifies the significance of each of these elements due to the heightened time constraints.

Jan 1, 2008

By T. W. Healy, W. J. Trahar

INTRODUCTION The flotation of minerals from their ores in flotation cells involves understanding many chemical and physical processes ranging from electronic events in the bulk mineral and in the mineral surface regime. molecular events at interfaces, the statics and dynamics of thinning and rupture of microscopic to molecular intefacial films, the fluid mechanics of bubble- particle events, the dynamics of air-water-solid colloid states in a flotation machine, etc. etc. D.W. Fuerstenau, whom we honour in this symposium has made unique contributions to many of these diverse physico-chemical and technological sub-processes. The present paper is concerned with a number of observations of the behaviour of minerals in flotation cells and the surface science of some mineral sulfide-water systems. We do not intend to be comprehensive in our analysis, but rather to highlight the challenges that face the scientific masochist who chooses to understand "froth flotationn. In what follows, emphasis is placed quite deliberately on technologically relevant, dynamic or realistic flotation processes i.e. the recovery in a froth of a given sulfide mineral particle of a given size and history from synthetic or actual ores in a flotation cell. The paper also attempts to use the understanding that is emerging from the area of photoelectrochemistry of colloidal

Jan 1, 1989

By James R. Yancik

Economical and environmental pressures necessitates the recovery of the minus 0.6 mm x 0 coal generated by todays mining machines. This size fraction, dependent on the type of production unit, maintenance of the production unit, and the Hardgrove Grindability Index, can be a substantial portion of the Preparation Plant feed. Historically, dewatering of the collected 0.6 mm x 0 product has often been rather expensive and marginal with respect to surface moisture reduction. The Freeman United Crown II Preparation Plant more than adequately demonstrates that the continuous scroll type centrifuge can dewater 0.6 mm x 0 coal to acceptable surface moisture levels.

Jan 1, 1981

By I. M. Konduri

Theoretical investigation and laboratory experimentation have shown a great potential for jet fan ventilation in mines. Jet fans, also called induction fans due to the induction effect of the fluid jet to ventilate headings, may have particular application in remote-controlled production operations. This paper summarizes ongoing research using a scaled laboratory model. The model uses water as a fluid medium and simulates a typical 25m long heading of 1.5mx6m cross-section. The effects of various nozzle positions and designs have been investigated by using still photography as a tool for flow visualization. It is also found that the use of jets in combination with line curtains has enhanced the overall ventilating effect in the model entry.

Jan 1, 1996

By David Cronan

"Most of the recent renewed interest in manganese nodule mining has been focused in the Clarion-Clipperton Zone (CCZ) in the NE tropical Pacific where nodules are rich in Mn, Ni and Cu. However, equally interesting, but compositionally different, nodules occur in the tropical central South Pacific (CSP). The CC Zone deposits lie in the International Seabed Area whereas those in the South Pacific lie mainly in the Exclusive Economic Zones of Island States, principally the Cook Islands and Kiribati. The CSP nodules should not be regarded as an alternative resource to CCZ nodules, as they are enriched in different elements. Rather, the CCZ nodules should be thought of as a source of one group of metals (Mn, Ni and Cu) and the CSP nodules the source of another group (see below), mutually complementing each other and to be mined in parallel for their different metals.Manganese nodule mining in the South Pacific has been mooted since the 1970s. However, new data on manganese nodule composition and abundance there have recently appeared. Also, a recently developed interest in &apos;rare&apos;, &apos;green&apos; and &apos;technology&apos; elements has necessitated a re-examination of old South Pacific nodule data for information on these elements (previously thought to be economically unimportant), and the re-analysis of the deposits to obtain new data on them. Additionally, current and possibly future applications to the UN to extend island &apos;continental shelf&apos; areas necessitates an appraisal of the manganese nodules in these areas. These developments have prompted recent work that has helped to refine our understanding of the distribution and abundance of metals of traditional interest in South Pacific nodules, namely Mn, Co, Ni and Cu, but has also drawn attention to other elements of possible economic interest including titanium (Ti), vanadium (V) and the rare earth elements (REE)."

Sep 1, 2014

By Sandeep Upadhya, Marc Morgan, Baljinder Bassi, James Fletcher, Mike Deevy, Nishant Nayan

"In order to protect public safety in the event of a deliberate fire attack, underground rail authorities are increasingly considering the need to design for arson-initiated fire scenarios. Where typical design fires for modern rolling stock mean a peak fire size is reached after 12 minutes, an arson-initiated fire reaches its peak within 2-3 minutes. We present the innovations required to successfully incorporate this requirement on a recent design-build project. In stations 3D modelling is used to optimise smoke reservoir designs, smoke chimneys, station boxes and tunnel geometry to allow coordination with structural requirements. In tunnels, novel coupling of one dimensional network modelling and 3D Computational Fluid Dynamics (CFD) is used to improve assessment of complex fire scenarios. Finally, the impact on tunnel structures is assessed through comparison with standard time-temperature curves and risk of explosive spalling. INTRODUCTION An increasing regulatory environment and the appreciable influence that terrorist incidents have had on public safety policy have motivated the need to protect against large arson fires, especially in civil structures and public transport systems. With a greater reliance of a growing urban population on underground subway systems, design of such infrastructure is continually being reassessed and developed worldwide. Underground rail authorities are paying increased consideration to the design of fires - with properties beyond the upper regions of growth and intensity - amongst arson fire studies. Use of fire hardened materials on modern rolling stock means fires caused accidentally can be expected to develop relative slowly. However, recent experiments involving large initiating fires (as would result from an arson attack) have shown rapid fire growth rates and flashover leading to greater maximum heat release rates, Hadjisophocleous (2012), White (2010), and Lönnermark, et al. (2015). This paper describes the challenges and innovations required to complete a detailed design to control smoke from such aggressive super-fast growing fires. Computational modelling is used to demonstrate the required smoke control design by configuring the mechanical exhaust system combined with careful coordination with the architectural and structural design. The design objectives are to provide tenable egress paths in accordance with NFPA 130 (2014) and fire-fighting access. Finally, analysis of the design fire is used to inform the tunnel lining design, reducing the risk of explosive spalling, protecting the asset in the event of a severe fire."

Jan 1, 2016