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By T. Hudaverdi

Several studies have been conducted on blastability and prediction of fragmentation. The term blastability is used to refer the susceptibility of the rock to blasting and is closely related to fragmentation. Parameters that determine fragmentation by blasting may be divided into two groups. The first group consists of blasting design parameters. The blast design parameters are controllable parameters and determined by the explosive engineers. The burden, spacing between holes, bench height, drillhole diameter, stemming height and explosive density are all design parameters. The second group consists of rock mass parameters that are referred to as uncontrollable parameters. The uncontrollable parameters are physical and mechanical properties of rock and rock mass structure. The strength, modulus of elasticity, density of rock, number of joint sets, joint orientation and joint spacing are among uncontrollable parameters. The rock mass parameters and blast design parameters should be considered together to explain fragmentation process. In this study, a blast database was accumulated to use for multivariate analysis. The blast database contains the blasts performed near Istanbul region quarries and the blasts that were preformed in various mines in the world by the blasting researchers. The cluster analysis was used to separate the blast data into different similarity groups. Group memberships were analyzed and checked by the discriminant analysis. Then, the multivariate regression analysis was used to develop a prediction equation for blast fragmentation for each group. Finally, a validation of the suggested models was performed for various mines. The model comprises blast design parameters, mechanical properties of rock and rock mass structure.

Jan 1, 2011

"The effective thermal conductivity (ETC) is one of the most important thermo-physical properties of porous media. Due to the lack of higher precision influence of temperature on thermal conductivity, we took 6 groups of experiments on rock samples (including igneous rock, sedimentary rock and metamorphic rock) under different operating temperatures from 20? to 50? by 7 acquisition points. The general equation of thermal conductivity drives the value of it increasing along with the decreases of the temperature. While in our experiments, it is easy to find a singularity among them for each sample. The experimental investigations we attempted to observe and interpret the alteration mechanism. According to the Heat Capacity Theory in solid state physics, this research gives the explanation about the “singularity” from 3 understanding of specific heat, average free path, and thermal conductivity. Our research divided the condition of the rock thermal conductivity into 3 different types. INTRODUCTION The effective thermal conductivity (ETC) is one of the most important thermo-physical properties of porous media(Huang & Han ,1988; Peierles ,1955). This parameter is necessary for analysis of heat transfer(Vaferi et al, 2014;Hans-Dieter & Rudiger,2003). It’s well known that a general equation for ?(T) was set by Sass et al. (1992) which based on the coupled effect of composition and temperature on the thermal conductivity(Jesse et al, 2013; Mongelli et al,1982).The equation was further successfully verified for other rock (Zumrud et al,2010;Abdulagatova et al,2009;Seipold& Huenges,1998).Thermal conductivity is also related to other physical proper ties of porous rock, such as thermal diffusivity, heat capacity(Brettmann et al,2011;Abuel-Naga et al,2008). It is well known that ETC and other thermo physical properties of rock materials are affected by various factors, such as temperature, pressure, mineralogical composition, porosity, stratification, size and shape of the components, and nature of pore fluid, etc. (Tiedje & Guo, 2014; Touloukian et al,1970).The understanding of heat transport processes still requires the knowledge of thermal properties of rocks."

Jan 1, 2015

By Dan A. Brown

The New Mississippi River Bridge (MRB) employed conventional design-bid-build procurement, but the bidding process included the opportunity for pre-qualified bidders to develop and propose confidential Alternative Technical Concepts (ATC?s) for evaluation and approval in advance of bidding. The ATC process provides a mechanism for value-engineering prior to bid, with incentives and opportunities for both the owner and the bidding contractor. The contract described in this paper is for the river bridge composed of a cable-stayed crossing with two pylons and the anchor piers on each side of the river. The Massman-Traylor-Alberici (MTA) team developed a re-designed foundation system for the main pylon and anchor foundations which utilizes their equipment and experience along with field load test measurements to optimize the foundations. The paper describes the experience with the use of the pre-bid ATC process on the project from the perspective of the bidder, and outlines some of the benefits and limitations of this concept with respect to foundation design and construction. Some keys for success are identified and impediments to the effective implementation of the process are described.

Jan 1, 2011

By G. B. Shea

"INTRODUCTION Much of the recent progress in increasing the efficiency of oil-well performance can be attributed to advancements in the art of cleaning wells. Through research and development by operators and service companies during the past decade, significant improvements in the application of engineering and chemical principles to well-cleaning technology have widened greatly the scope of ""clean-out"" methods to the end that greater ultimate recovery of oil will be attained.This report reviews recent improvements and developments on this important problem in California; it describes also the use of various methods and tools for cleaning wells to stimulate or revive their productivity. Developments in preventing and removing mud sheaths in well-completion operations also are described. The report is based on a field survey, supplemented by data from the technical and patent literature and from manufacturers' catalogs, which contain much valuable information.In preparing the material for publication as a Bureau of Mines report, the author has been fully aware of certain limiting conditions that attend the discussion of a subject such as that treated in this report. The following are examples:1. To a considerable extent, well cleaning in California is done with tools rented from service companies, and their representatives and employees are specialists in jobs of this type. They usually have working experience with their own equipment and methods which greatly exceeds that of persons whose interest has been casual or who have had no opportunity to study the subject in detail in actual practice. Many of the tools and methods are covered by letters patent for the protection that may be in developing and successfully applying these mechanical and chemical means of increasing the production of wells. Frequently several years have been required to perfect a given tool or technique, requiring relatively large investments to establish a service that is remunerative to those who have primary interest in a certain development and at the same time attractive enough to the operators of producing properties (because of greater quantities of oil delivered into the flow tanks) to warrant employment of or contractual agreements with a particular service group."

May 1, 1943

By M. I. Copeland

The investigation of the iron-gadolinium phase diagram is part of a project undertaken by the Bureau of Mines and sponsored by the Atomic Energy Commission to investigate rare-earth alloys. Data from the investigation of the iron-gadolinium phase diagram revealed a single eutectic system with very limited terminal solubility and three intermediate phases. The eutectic point occurs at about 85 percent gadolinium, and the eutectic isotherm, which occurs at 850° C., extends from the compound Fe2Gd to 99-plus percent gadolinium. Very little solubility of the solid phases in each other was observed. The three intermediate phases, FegGd, Fe3Gd, and FeaGd, melt incongruently at peritectic isotherms at 1,320°, 1,150°, and 1,080° C., respectively. The crystalline systems of the three phases were determined as follows: FegGd, hexagonal; Fe3Gd, hexagonal or rhombohedral; and FeaGd, face-centered cubic. No lowering or raising of the alpha-gamma iron transformation at 910° C., the gamma-delta iron transformation at 1,388° C., or the gadolinium transformation at 1,262° C. was observed. The principal methods used in determining the iron-gadolinium phase diagram were melting-point determinations, thermal analyses, metallographic examination, and X-ray diffraction analyses. Melting, heat treating, and thermal analyses were conducted in a vacuum or under a helium atmosphere because of the avidity with which oxygen combines with gadolinium at elevated temperatures. A few hardness values were determined, but they had no part in the derivation of the phase diagram. No other mechanical properties were determined.

Jan 1, 1962

By R. T. Richins

Coeur d'Alene Mines Corporation (CDE) is a precious metals mining company. The company's three mining operations are located In Nevada and Idaho. Collectively, these mines (Rochester in Nevada, and the Galena and Coeur In Idaho) produced about 61,000 ounces of gold and more than 7.5 million ounces of silver in 1991. The company is currently planning the development of two major properties; the Fachinal gold-silver project in Chile and the Kensington gold project near Juneau, Alaska. Fachinal and Kensington hold encouraging potential to significantly expand CDE's gold production during this decade. The permitting process for these two distinctly contrasting environmental settings, project design requirements and regulatory/political circumstances provide the basis for a comparative analysis of licensing and permitting requirements, timeliness of the permitting process and costs in the U.S. and Chile.

Jan 1, 1993

By A. O. Dufresne

The mineral wealth of pre-Cambrian rocks in Canada has been the subject of much study by geologists and engineers (members of this Institute), particularly so in the past few years, following discoveries of mineral deposits in areas far a part. This interest is well worth sustaining knowing the numerous rich producing mines within the pre-Cambrian formations, and the vast area covered by its rocks throughout this country. The pre-Cambrian has yielded minerals, both metallic and non-metallic; of these a much diversified list could be made. In more than one district we can point to mining as being responsible for the opening up of new sections, attracting a population into regions which otherwise would have remained virgin land of little commercial value. In these pre-Cambrian formations are found the rich copper deposits of Michigan, producing without interruption since 1845, and from which seven billion pounds of copper has been won; while in Minnesota and the adjoining district, at the head of Lake Superior, are mined iron ores which have rendered possible the great steel manufacturing industry of United States, the base of the economic structure of that wealthy country. The pre-Cambrian has given Canada the nickel-copper mines of the Sudbury district, the silver deposits of Cobalt and the gold camps of Porcupine and Kirkland Lake. With all of these our members are familiar; and it suffices to mention them to bring to mind pictures of the wealth and 'the growing population, in a word the importance of mining in?those sections of the country.

Jan 1, 1926

By U. Richter

Conveyors are a highly effective means of transporting material over long distances. Recently there has been a trend toward long conveyor systems with high capacity single flights. These conveyor systems are an efficient alternative to costly truck fleets. Also with deeper mines, the use of diesel driven trucks becomes more difficult. Another trend is in underground mining, where conveyors are an efficient alternative to drift hoists or dedicated rail systems.

Jan 1, 2012

By Kenneth C. Ko

An engineering investigation was carried out on the technical and economic feasibility of implementing flexible liner/backpacking support systems In an advancing tailgate longwall mine. The system for a model mine consists of a circular tube constructed of liner plates and flyash backpacking. Flyash is pneumatically stowed into the tailgate. Small amounts of cement may be mixed to improve the support capability of the fill In difficult local ground conditions. Water is added inside the nozzle immediately prior to spraying. Results of theoretical analyses and a field test show that the designed system is technically feasible, can be cost-competitive, provides more stable ground conditions, and can Increase productivity and coal recovery, when compared with existing retreat longwall systems. In certain mine layouts, the new system can reduce the direct mining costs by a significant amount. The system would be particularly applicable to deeper coal beds with bad ground conditions.

Jan 1, 1980

By George H. Holmes

The water situation in Nevada mineral and related industries is described in this report. It contains information on the sources and adequacy of supply to current operators, requirements and uses, quality and costs, geography, hydrography, precipitation and evaporation characteristics, and Nevada water laws. Also, information is given on the water requirements of one public utility powerplant, and the source and consumption of water in four major cities. Water distribution at 24 operations is shown on schematic waterflow diagrams. The mineral industries of Nevada in 1962 used 8.6 billion gallons of nee' water and reused 3.8 billion gallons for a total usage of 12.4 billion gal¬lons. The copper industry was the major water user. The 1962 value of all mineral production in Nevada was $85.5 million. The large amount of water required to maintain this high production is obtained principally from ground-water sources in alluvial valleys and the permeable rock formations of some mountain ranges. Some water is also obtained from perennial streams and springs. Sources of water utilized by existing industry ore near most mineral industry operations; however, seven companies are forced to pipe water distances ranging from 2 to 8 miles. Although water supplies of presently operating companies are adequate at most operations, several companies resort to large-scale reuse of water as a matter of conservation and economics. Acquisition of water by new operators is possible but takes considerable negotiation. Water rights, surface and underground, are controlled by the State. The quality of the water is satisfactory for most purposes. Analyses of 19 samples, listed in the appendix, show the range in water quality at various plants throughout the State. Costs of delivering new water to current operations range from 2 to 26 cents per 1,000 gallons with an average of 10 cents per 1,000 gallons for power and maintenance. No firm costs for recirculating water were available; estimated costs range from 1.5 to 2.5 cents per 1,000 gallons. The mineral-product value of the entire Nevada mineral industry in 1962 was equivalent to $10 per 1,000 gallons of new water and $26 per 1,000 gallons consumed. Projection of the 1962 water requirements of the Nevada mineral industry indicates that the demand for new water will increase from 8.6 billion gallons in 1962 to 11.9 billion gallons in 1980, a 43-percent increase. Water requirements ill the year 2000 are estimated as 14.8 billion gallons, an increase over 1962 water demand of 78-percent.

Jan 1, 1966

By M. Zanotto

[ ] A period of heavy rains caused the river Adda to flood parts of the Valtellina, one of the Alpine valleys of Northern Italy. The exceptionally high waters put under considerable strain the whole system of embankments and levees controlling the river and protecting the adjacent towns and lands. In some places the water breached and washed away the embankments, submerging large tracts of cultivated land, buildings, roads and railway tracks. The town of Talamona, in the lower Valtellina, was hit particularly hard: in its proximity the river overrun and then washed away 300 m (1,000 ft) of embankment (see vicinity map, fig. 2), depositing large amounts of riverbed debris onto over 400 hectares (1,000 acres) of fertile land.

Jan 1, 1992

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Kagan Ozdemir

In the condition that drilling and blasting technique is inevitable depending on the rock mass and material characteristics on mining activities, the fragmentation rate and particle size distribution of the muckpile after blasting has important influences on the performance of subsequent mining activities such as loading, hauling, crushing, grinding etc. and the total costs of that mine. Drilling and blasting is an important step in this process chain and it's results such as fragmentation, muckpile shape and looseness, dilution, damage and rock softening effect the efficiency of downstream processes. There is an increasing body of blasting research indicating significant impacts in these downstream processes.

Jan 1, 2007

By N. Abdel-Khalek, A. Youssef

The tailings from beneficiation of Florida phosphate ore contain considerable phosphate values. These tailings are currently discharged into large disposal areas. More than three million tons of P2O5 are discarded with the phosphatic slimes (clays) in Florida each year. These phosphatic clays not only create one of the most difficult disposal problems in the mining industry, but also represent a tremendous loss of P2O5. As the quality and quantity of Florida’s phosphate reserves diminish, recovery of phosphate values from these wastes becomes more vital. This will also significantly lengthen the life of these important phosphate resources. Thus, it is the goal of this study is to recover more than 80% of the phosphate values in phosphatic clays. A systematic study to characterize samples taken from inactive disposal area has been conducted. The data suggest that natural segregation takes place in the settling pond. In other words, coarser particles settle closer to the feeding point of the pond. Flotation tests were conducted using the +325 mesh fraction of samples obtained from sites close to the feeding point (sample# A) and further from that point (sample# B) and (sample# C) which is even further away from the feeding point. The results show the following: Sample# A gives the highest grade and recovery, followed by that of # B and then of # C. There is a great potential to upgrade sample# A where concentrates of high grade (68.9-70.1 % BPL or 31.5- 32.1% P2O5) and recovery (~86.6-95.4 %) can be obtained under the investigated operating conditions (1.0 – 2.0 kg/ton sodium silicate and 1.5—3.0 kg/ton collector mixture of fatty acid and fuel oil). The mineralogical and chemical analysis of all samples is presented in this paper for comparison. Only in this paper, the flotation data of (site # A) are discussed below.

Jan 1, 2002

By Timothy J. Rohrbacher

This report presents results from an ongoing U.S. Bureau of Mines study defining domestic coal reserves. Examinations of five 7 ½ -minute central Appalachian quadrangles have been completed to date. Only 26.4%, 5.0%, 6.5%, 8.2%, and 4.2% at the coal resources remaining in the Matewan, Boltsfork, and Hoskinston, KY; Vansant, VA; and Beckley, WV quadrangles, respectively, constitute economically recoverable reserves. An evaluation of the coal mining industry's impact on the economy of Pike County, KY, wherein the Matewan quadrangle is located, was also completed in order to provide a basic understanding of the influence of coal mining on the local economy. Results show that coal mining is the only major income producing industry in Pike County, accounting for about 46% of the county's income, and 21% of the total available employment, in the base year 1990. If similar results are found in subsequent investigations, a strong argument can be made that traditional coal producing regions may soon be experiencing resource depletion problems far greater and much sooner than previously thought. This will affect not only the coal industry but, given the obvious dependence of Pike County's economy on its coal mining industry, the entire social and economic infrastructure of large areas.

Jan 1, 1994

By J. A. L. Napier

It has been established that significant time-dependent stope convergence may occur over time periods of hours and days in certain hard-rock gold and platinum mines. The source of this time-dependent behaviour appears to be associated with both pre-existing discontinuities and with mining-induced fractures that form near the stope face. These induced fractures may be associated with blasting processes and may also be formed in response to high stress concentrations in the unmined regions immediately ahead of the stope face. In shallower platinum mining operations, time-dependent behaviour is, however, observed to be much less marked unless some form of specific mining-induced fracturing occurs. One particular case of considerable interest is the time-dependent behaviour that is found to be associated with the formation and deployment of crush pillars. The purpose of the paper is to present a simple limit-equilibrium computational model of this behaviour that is sensitive to both the formation sequence and the size of planned crush pillars in a mine layout. This model provides a useful means to optimize the sizing of crush pillars, and at the same time may be used to identify potentially hazardous circumstances in which pillars may not crush in a stable manner.

Jan 1, 2012

By Dave Stefanuto

Voisey?s Bay Project Components ? Mine/Mill Port In Labrador ? Mini Plant in Mississauga ? Demonstration Plant in Argentia ? Supply Vessel (Umiak1) ? Transshipment Facility (Quebec) ? Concentrate Handling & Transport to Sudbury/Thompson ? Cobalt Refinery Upgrade (Thompson) Project Setting ? The Project is on the traditional lands of the Labrador Inuit and the Labrador Innu ? Canadian courts have held that Aboriginal peoples in Canada possess special rights to traditional Aboriginal lands Those rights can include requiring resource developers to enter into Impacts and Benefits Agreements (IBAs) on traditional lands to set forth how lands can be used and benefits to be received by Aboriginal people

May 1, 2006

By E. L. Rawlins

Systematic leakage surveys of natural-gas transmission lines not only aid in the conservation of gas, but can be made to show direct financial returns of large magnitude. 1. Such surveys reveal the actual leakage from the lines, and indicate repairs to be made in order, to eliminate unnecessary waste. 2. Tests on lines, after repairs are made, show the actual saving that has been accomplished. 3. Tests on newly constructed lines reveal the presence of leakage that should be eliminated before the lines are put into service.

Jan 1, 1926

This paper discusses current workforce demand projections for mineral processing engineers and emerging trends in mineral processing education. Attempts are made to identify gaps that often result in a mismatch between skills taught and skills needed by the practicing engineer. Clear examples of this include a less than uniform training in chemical aspects of mineral processing, and an understanding of the statistical and experimental design tools necessary to tame the often-large variation in operational parameters and plant data. The end goal is an educational system modernized to prepare mineral processing specialists for productive careers in the sustainable development of natural resources. A framework for revamping education based on an integrated modular approach is also presented. Keywords: mineral education trends, mineral processing programs

Sep 1, 2012

A combined reflection seismic and magnetic survey off the south coast of New South Wales has revealed six distinct reflection horizons within the Lower Triassic-Upper Permian sequence, and has enabled the upper part of the lllawarra Coal Measures to be mapped in considerable detail. Large magnetic anomalies in the eastern half of the survey area appear to originate in the Gerringong Volcanic Sequence which forms the magnetic basement in the survey. Small residual anomalies in the western half of the area can be correlated with small scale faulting and folding in the upper part of the llawarra Coal Measures, as revealed by the seismic reflection survey.A synclinal axis striking at approximately 55° has been mapped near the western margin of the survey area, and areas of faulting and folding have been outlined by combined analysis of seismic and magnetic results.

Jan 1, 1970

By J. C. Edwards

A series of four coal combustion experiments (I)' was conducted at the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory in the Safety Research Coal Mine to evaluate the response of optical and ionization smoke and CO sensors to a small 0.61 m square smoldering coal fire which transitions to flaming combustion in the presence of diesel emissions. With the increased utilization of diesel engines in underground coal mines, it is important to be able to discriminate fire products-of-combustion (POC) from diesel emissions. One proposed method to accomplish this is the deployment and interpretation of multiple sensors.

Jan 1, 2010