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By C. H. Grant

On the Mesabi Range, Ammonium Nitrate is used for blasting a variety of materials having widely varying blasting characteristics. The materials vary from hard, dense, magnetic taconite, which requires heavy blasting, through relatively soft, earthy, direct shipping ores, which require only light blasting to facilitate shovel operation. In view of the fact that materials gradational between these two end members are encountered in large tonnages, it is evident that a wide range of blasting situations face the mine operators on the Mesabi Range. In April of 1956, at Cleveland-Cliff s Hawkins Mine near Nashwauk, Minnesota, a fertilizer grade of Ammonium Nitrate prills was first used as a blasting agent. This first attempt was made without the addition of any carbonaceous material and even though it did go off, the force was not sufficient to produce the required results. Fuel oil was then added In the amount of one gallon for each 80 pounds of Ammonium Nitrate, with the oil and Ammonium Nitrate being added to the hole simultaneously. This blast was successful. Since then most of the mining companies have used Ammonium Nitrate, experimenting with various ratios of oil and fertilizer, mixing these ingredients either before or during loading of the holes. Since the additional of fuel oil to the Ammonium Bitrate before loading produces a more uniform saturation, most companies have adopted the method of pouring the fuel oil directly into the Ammonium Nitrate bags and then pouring the mixture into each hole. The ratio of 3- ½ quarts of fuel oil to each 80 pound bag of Ammonium Nitpate prills is now being used.

Jan 1, 1958

By Dan McCutchen, Oettmeier

Kelly bar drilling and blasting is unique to Florida, the' Bahamas and other marine limestone areas in the world where blast holes are required but will not remain open for the loading of explosives. This type of rock formation usually yields 1.5 tons of recoverable rock compared to 2.2 tons per cubic yard for competent limestone. The loss of .7 tons per cubic yard is due to voids and sand in the formation. These deposits all contain water to the top of the blast holes which are collared only a few ft. above the ground water level. The working pit is a water filled lake which is excavated from the bank by draglines. These drills have been used in Florida for many years to depths of 65 ft or less.

Jan 1, 1991

By E. R. Phelps

It is very seldom that a completely new project is initiated. Most projects consist of a new and different combination of proven techniques or a combination of proven and new techniques. The theme of my discussion today falls in the second category. Proven methods of water transportation and proven methods of bulk material handling were combined with some new techniques which resulted in a new market for the coal industry and a cheaper fuel supply for the power industry. In this respect I refer to the water transportation of coal from the West Kentucky coal fields to coal burning power plants on the west coast of Florida. Peabody Coal Company, Florida Power Company, Gulf Coast Transit, and Mid-South Towing combined their individual requirements and "know how' to make this project possible. I feel the results speak for themselves since it proves that coal can be mined in the West Kentucky coal fields, transported some 1,200 miles by river barge and some 450 miles by ocean going barges, be delivered to power plants on the west coast of Florida and still meet the competitive prices of gas and residual oil. The unique parts of this project concerns the storage and trans loading facilities for coal from river equipment to ocean equipment near New Orleans; the return haul of phosphate and it's trans loading from ocean to river equipment at the same facility and the use of large ocean going barges. In detail it works as follows: Coal is mined in West Kentucky and loaded into 1,500 ton river barges on the Green River. It is then transported some 100 miles to the mouth of the Green on the Ohio River, then 200 miles down the Ohio to it's convergence with the Mississippi, and then 900 miles down the Mississippi to the trans loading facility some 40 miles South of New Orleans. There it is transferred from the 1,500 ton river barges to 18,000 ton ocean going barges and hauled some 450 miles across the Gulf of Mexico to the Gannon Station of Tampa Electric at Tampa entailing a total haul of approximately 1,650 miles.

Jan 1, 1966

This report, the third in an annual series, outlines recent trends and developments in the minerals industry. Discussed are new methods, equipment, techniques, and systems used to more, effectively extract and process minerals and fuels. Environmental considerations, reduced ore grades, and the related increased quantities of material handled were the dominent concerns of the minerals industry in 1972. Productivity increased in most mineral commodities as equipment became more mobile, versatile, and sophisticated. Increasingly, equipment designs incorporated health and safety features. There was considerable interest in the field of energy and in pollution-free metallurgy processes.

Jan 1, 1973

By Diane Jones, Jeremy Spearman, Tom Matthewson

Requirements for minerals are on the increase globally and the deep sea offers a potential source of essential materials. Extracting these minerals from what is considered an environmentally sensitive area, and one about which little is still known, is a challenging activity, which needs careful consideration and an appropriate environmental impact assessment to be carried out. Extraction of material from the deep sea beds can cause disturbance or damage to benthic communities; impact on mobile marine species such as fish, mammals and reptiles; cause increases in suspended sediment and sediment deposition onto potentially sensitive areas or potentially release contaminants which were previously bound to the sediment. This paper discusses the potential environmental issues surrounding extraction of deep-sea deposits using aggregate dredging techniques and how those issues can be appropriately assessed. In particular issues of suspended sediments, plume transport, water and sediment quality and underwater noise impacts on potentially sensitive species and habitats will be explored.

Sep 1, 2014

In subterranean mining operations, access to communication networks deep underground is critical for transporting data, voice and video, and other supporting applications that are essential for efficient and safe operations. Whether accessing sophisticated ERP or maintenance management systems, engaging in fleet management, video surveillance, or access control, or protecting miners with wireless locator systems, these networks serve as a literal lifeline between workers deep within mines and surface operations. For this, mining networks require more than permanently installed network cabling, it also requires unique deployable systems designed for quick installation, extension and even relocation as the active mine site area moves, or equipment is moved in and out.

Mar 1, 2014

By Robert L. Davidoff

INTRODUCTION The impact of taxation differs substantially from state to state in a complex fashion that depends on both the physical characteristics of a mineral deposit and on the price of the mineral commodity relative to its costs of production. A comparative analysis of the tax structures of eight states (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah and Wisconsin) showed wide variations in rates of return for any given type of mineral property, with no state having either the most burdensome or least burdensome tax structure under all circumstances. Three hypothetical mineral operations were analyzed: a producing open-pit copper property, a non-producing underground platinum operation, and a non-producing underground gold operation. None of them corresponds exactly to an existing property. Each of these property types is further defined to have ore feed grades at three different levels, leading to three potential profitability levels, referred to in this paper as "economic", "marginal" and "subeconomic". Thus the differential impact of state tax structures is measured for mineral properties of different types, as well as for different profitability levels. Montana is used as the base case. This study does not address the topic of corporate structures or tax consolidation. There are no costs assumed external to the operation of the deposit (e.g. exploration to locate additional deposits). Two types of analyses were performed for this study. The first calculates the total cumulative tax payments in each state using all applicable taxes (including U.S. federal income taxes and examines the resultant differences in discounted cash-flows rate of returns DCFROR's amoung the eight states. The second is a sensitivity analysis that examines each type of state tax separately (i.e. state income, property, and severance taxes) in order to isolate and examine the differences in tax payments that are due to the difference in rates and methods of computing specific types of taxes in each state. The results of this study serve to illustrate the complex nature of interactions among various taxes. For example, property tax is a deduction in calculating severance tax in some state. Changes in property-tax and severance-tax payments both enter into the calculation of state and federal income-tax liability. This, in turn, could change the timing and usage of tax-loss carry forward amounts and investment tax credits. Additionally, the physical characteristics of a property, the method and costs at which the mineral will be extracted, and the profitability level at which each property operates will affect tax treatment. Each mineral operation was evaluated at three different predetermined profitability levels, referred to using the terms economic, marginal and sub-economic. These three profitability levels are defined by the ore feed grades of the primary commodity that yield in constant terms, approximately an "economic" 18% DCFROR, "a marginal." 10% DCFROR, and a "sub-economic" 5% DCFROR, respectively, under the Montana tax structure. In the analyses, the mining and processing parameters for each of the three types of properties were assumed to be identical for each of the eight states. It was assumed that each operation produces at full operating capacity throughout its life. This implies the level of mineral commodity demand will support the inferred commodity price, such that each operation will be able to sell all its output. The analyses performed for this study were done using a comprehensive economic evaluation simulator that is used in the Bureau of Mines, Division of Minerals Availability MAS program to perform DCFROR analyses. All economic evaluations performed upon these data (see appendix 2) were in constant January 1981 dollars. By-product prices used for the analyses were: [Gold $425.00/troy ounce Palladium$200.00/troy ounce Silver $ 10.00/troy ounce] Typical cash-flow calculation layout is given in Appendix 3. The initial step for each evaluation is to define an "economic" profitability level scenario. An 18% DCFROR rate in Montana was considered the

Jan 1, 1985

By Kathy S. Kalenchuk

Damages have been observed in shafts, backfill infrastructure and the slick line at the Leeville Mine. Shaft damage (shearing and spalling of the concrete liner) is attributed to mine-induced rock mass deformations concentrated where regional faults intersect the shafts. Aggregate bin, mixer station and conveyor drive damage (shotcrete shearing, heave of concrete floor slabs and bending of a vertical steel beams) is attributed to rock mass squeezing induced by elevated magnitudes of the vertically orientated major principal stresses. Separation of the slick line has occurred do to extension of the stressshadowed rock mass immediately above the mined out areas. Three-dimensional numerical models have been developed and calibrated to simulated rock mass deformations with magnitudes similar to those believed to have produced the observed damages. By stepping through the mine sequence, models reproduce deformations at the same mining stage as when damage has occurred. Calibrated models have been used to forward project further damage over the remaining mine life.

Jun 1, 2012

By George E. Thackray

In December, 1894, the Cambria Iron Company made a number of heats of Bessemer steel to be used in structures by one of its customers, subject to inspection and tests by a firm of consulting engineers, one of the requirements being that the material should riot exceed .08 per cent. of phosphorus. In other respects the requirements were such that they could only be met by material of good quality; but the general spe cification is not introduced here, as it is not the purpose of this paper to deal with anything except certain difficulties encoun tered in determining the phosphorus-content of the material in a manner satisfactory to both seller and buyer. Preliminary determinations of phosphorus were made in sample-ingots from each of the heats from which material was rolled for the order in question, and these preliminary chemical tests, made in the laboratory of the Cambria Iron Company, showed that, with very few exceptions, every heat was within the prescribed limit of phosphorus. After the material had been rolled, sample-drilling8 of finished material were taken from the various heats in the regular manner in use at the works, these samples being thoroughly mixed and divided into two parts, one of which was analyzed at the works' laboratory and the other sent to the inspecting engineer. Several hundred determinations were made from this mate rial without reaching an agreement between the work of the inspector's chemist and that of the works' chemist; but as it is not the object of this memorandum to treat of this part of the subject at length, it is considered sufficient to present herewith only a few of these first determinations. The analyses given in Table I. are those of the original series made on the heats which were afterwards resampled for final determination by an arbitrator; and they are selected for this reason, as the entire " comparison is thus rendered more complete.

Jan 1, 1896

By John R. Green

ROTARY kilns, varying in construction, are used in a variety of processes. Products differ and operating conditions vary according to economic requirements. All of these variables influence the degree of instrumentation and type of control necessary or profitable to install. Products fired in rotary kilns are the results of combined temperature and time treatment and the interrelation of these two factors should be kept constantly in mind in the perusal of this paper. MEASUREMENTS OF KILN TEMPERATURE The securing of proper temperatures within the rotary kiln, either of the charge or of the kiln lining in the high fire zone, are basic objectives of kiln operation; therefore the measurement of these high-temperature conditions merits first consideration. For these measurements, radiation pyrometers, properly designed and protected, have proved adequate, particularly where records or automatic control are desired, while optical pyrometers may serve as portable indicators. Light-sensitive devices or photoelectric cells in this service are capable of producing records as well as certain forms of automatic control. High-temperature measuring devices for rotary-kiln work should have the measuring unit protected from dust, as a continued accumulation of deposit would lower the readings. Fig. I shows a typical application of radiation equipment to a rotary kiln, mounted far enough away from the sighting hole through the kiln hood to be protected from puffs or stingouts and with a sighting tube having a series of settling chambers, to prevent dust from reaching the lens. Although dust conditions inside the kiln itself usually fluctuate considerably and have their effect upon the readings at that moment, such effects are not cumulative and show as a continuous fluctuation in the temperature indicated, provided the radiation unit and recorder are responsive to such slight and rapid temperature fluctuations. The ambient temperature to which a measuring unit is subjected fluctuates from possibly 0° to over 200°F., therefore these changes should have no effect upon the final reading or upon the life of the measuring unit. A very narrow sighting angle is desirable, so that measurement of temperature may be made as far as possible into the high fire zone without effect of the flame temperature. There should be some sighting means on the measuring unit, so that the proper field may be viewed. Measurement of wall temperature taken at a point where the charge has just left the wall is less affected by dusting conditions than when taken elsewhere. Factors Influencing Temperature Table I gives an outline of the factors that produce kiln temperatures and comments on the possibility of measurement and control. Of greater number and of varied influence are the factors that control when, where and how the heat is delivered to the kiln, the type of flame and the rate of

Jan 1, 1941

By Ray Jambakhsh, Gabrielle Bourget

In the summer of 1998, Ontario Hydro awarded a contract to demolish an obsolete and inefficient chimney by blasting. The Ontario Hydro Thunder Bay Thermal Generating Station (T.G.S.), is a fully operational hydro thermal generating station located in Thunder Bay, Ontario, Canada. The Chimney was a 356 ft (108 m) high freestanding structure constructed of reinforced concrete with a brick liner. Falling the chimney required careful planning due to the highly sensitive structures and equipment which surrounded it. Damage either sustained to the existing systems through ground vibrations or direct contact would have resulted in expensive power outage and/or lost production. The role of Explotech Engineering Ltd. on this project was to provide and evaluation of the proposed demolition procedure, defme the predicted and maximum seismic vibrations at sensitive structures including underground services, conduct pre-blast / post-blast inspections and recommend various safety precautions. The general contractor for the project, LeBrun Northern Contracting Ltd., of Thunder Bay, Ontario was responsible for all site preparations and post-blast clean up. All demolition blasting calculations and operations were conducted by Dykon demolition experts from Tulsa, Oklahoma. On September 13, 1999, the chimney was successfully demolished. Extensive analysis of the vibration records and visual post-blast inspections of the surrounding structures concluded that the demolition event induced no damage to any of the Ontario Hydro facilities.

Jan 1, 2000

G. R. Compton (Gold Mines of Kalgoorlie (Australia) Ltd., Fimiston, W. A.) : In congratulating Mr. Hooker upon his resume of Mr Parry's paper I have in mind the fact that he carried out the research into pipe pressures. Hydraulic filling as practised in Kalgoorlie has created world wide interest, with these pressures and percolation being vital points.Early in the 1950s, representatives of the Kolar field were conduGted over the local mines where stopes at depths below 2,000 ft were being filled. The problems of pipe pressures were their main consideration since depths of up to 10,000 ft were envisaged.Mr Krishnaiah and Mr Murthy from the same field are with us today and perhaps we may hear of their experiences with depths of 6,000 ft and long lateral lines.J. Holly (Lake View and Star Ltd., Fimiston, W.A.): There is one phase, which I would like to mention myself, that has been very evident in Kalgoorlie operations. That is, we do not get the percolation properties that are obtained on many other fields in the world, and our tendency here has been to assess the quality of our fill more by its settling rate, i.e. the rate at which we can draw off clear water at the surface of the filling levels, rather than the rate that this water percolates down through the fill before it consolidates.We are tending now to measure the quality of our fill as a settling rate rather than as a percolation rate.Americans talk about percolation rates being the important property: If anyone has any experience on operating with fills with different percolation rates, I think their views would be very interesting to the meeting art this stage. Mr ...

Jan 1, 1965

By C. G. Dunn

Identification of the kinds of orientation relationships that may exist among crystals is an important problem in the metallurgical field. As an aid to its solution standard orientations of several orders of twins would be very useful for rapid analyses to discover high-order as well as low-order twin relationships. Although data have been published that give orientations for three generations of twins, these data are not readily useful in the form presented; i.e., in a stereo-graphic projection with one pole per orientation.' However, accurate data based on calculations of the positions of all {1001 planes for such groups would be very useful when presented in tabular form. Therefore, calculations have been made for a group of four orders of twins and the data are listed in Table 3. Illustrative applications are considered briefly, with the idea of pointing out what may be done with large groups of orientations. Method of Computing Orientation OF a Twin It is common practice to describe the orientation of a crystal in terms of the positions on a stereographic net of the poles of certain planes of the crystal. A single position on a net may be given in terms of two angle variables, two sets of which appear in the following equations: Polar Net Wulff Net x = , sin ?p cos Fbp x = r COS ?w y = r sin ?p sin Fp y = r sin ?w cos Fw % = r cos ?p z = r sin ?w, sin +, The three numbers z, y and z determine a length r as well as a direction (0, 4) in an X, Y, Z coordinate system. In the present case, r will be set equal to (h2 + k2 + L2)1/2, where h, k and I are the usual Miller indices for a crystallographic plane, a restriction that facilitates determination of the positions of poles of new planes from those of old or known ones,2 as will become evident later. Furthermore, since twinned lattices have certain planes in common, it is an easy matter to determine the orientation of a twin of a crystal if the orientation of the crystal itself is known. We start therefore with a crystal of known orientation (positions of three {Ioo} poles given) and determine where the cube poles occur in first, second, third and fourth-order twins. Methods for identifying twinned lattices and for making the calculations to find the orientation of a twin have been published.3,4' Reference 4 will be illustrated in the calculation of the orientation of a twin, even though this method differs from the one used by the writer in obtaining the following data on four orders of twins. Consider a crystal S and its twin A1, A' being one of the four {112} or {III} type* first-order twills of S. The orientation of S—i.e., the positions of poles of (I00)

Jan 1, 1945

By J. M. Mutmansky

A number of previous publications have attempted to provide the practicing ventilation engineer with simple guidelines on the optimal velocity to be used in mine openings. Some of these velocities were meant to be used in metal mining operations and some were meant for coal mining. A careful review of these publications reveals that the optimal velocities were determined based upon assumptions that are not existent today. As a result, they are not suitable for use in a modern coal mine. This paper takes a new look at this problem and determines a statistical relationship for optimal velocity that can be applied under both current and future conditions. The analysis performed here is based upon the determination of the optimal velocity for coal mine entries under variations in power cost, mining cost differential, airway friction factor, time value of money, airway lifespan, and quantity of air carried. A total of 8400 different conditions were analyzed for optimal velocity using computer calculation of the capital and operating cost values. Using the individual values of the optimal velocity derived in the calculations, a linear regression equation was fitted to the data to relate the optimal velocity to the other six variables outlined above. This regression relationship allows the ventilation engineer to make an easy, rapid determination of the optimal velocity.

Jan 1, 1984

By R. D. Grove, M. F. Elliott, R. L. Weigel

The control of Florida phosphate flotation plants is largely based on the visual observations of experienced operators, both in recognizing good and bad froth conditions and in making judgments about the composition of feed, concentrate and tailing streams. Chemical analyses lag the process by at least two hours and therefore only assist in recalibrating the operators' vision when major deviations occur. An image analysis system has been developed by IMC Agrico Company (IMCA) to improve upon the accuracy and precision of the composition estimation process. It still relies upon the operator taking a representative sample, but provides a measurement in about 15 minutes after that sample is obtained. This paper describes the system and its use and presents comparative results for various process streams.

Jan 1, 1993

By Marketa D. Evans

The mining industry has a significant opportunity to capitalize on its past learnings in order to build better social relationships. The industry?s relationship with society is both critical and under pressure. Rising levels of public opposition and social conflict are already having material impacts on operations around the world. Industry has an opportunity to shape the future direction of this social engagement, build public trust and proactively respond to a material risk to operations, but first it needs to better understand the nature of the challenges and the urgency of addressing them.

Aug 1, 2013

By Gustavo Armijo

Slippery and unstable working platforms spoiled not only by natural weather conditions but also by the effects of the construction process (drilling mud, grout slurry) are among the main sources of hazards. Due to this fact a set of recommendations for execution and maintenance of working platforms are presented in this paper, which is based on a study on this subject that is being carried out by AETESS, the Spanish Federation of Geotechnical Contractors. The main objective of this paper is to establish the basis for the right execution and maintenance of working platforms for geotechnical jobs with the idea of increasing safety and productivity. All the aspects involved in working platform safety are analyzed: ground and equipment characteristics, geometric conditions and working platform maintenance. From this analysis a set of general requirements is proposed together with the necessary specific controls before and after the equipment arrival to the job site. In order to facilitate this analysis some flow charts and tables and specific appendixes for each geotechnical technique are included.

Jan 1, 2006

By Douglas A. Anderson

Much progress has been made in understanding the forward process for blast vibration simulation: that is, how to create a resultant seismogram from an empirically determined seed waveform. What has not been successfully investigated to date is the reverse process: Determining the contribution of each borehole to the resultant seismogram. It might seem that these should be two sides of the same coin, but the reverse process is much more complicated. That is because the source, geological path, and receiver contributions must be unraveled and then dissected. If that can be done, a relationship can be developed between the seismic source properties and the explosive interaction with the surrounding rock. This paper presents a first step in the unraveling process, through analysis of blast seismograms using wavelet transforms.

Jan 1, 2013

By Madgwick J. C

A new strain of Thiobacil/us ferrooxidans (SPK I) has been isolated which has a higher copper to iron release ratio (2.04) than the standard T ferrooxidans (CPBI) (1.12). The diminished iron oxidizing ability enables almost quantitative release of copper (93 per cent) from a chalcopyrite-rich concentrate without interference by iron reprecipitation. In a single batch leach, Bougainville copper concentrate yielded 9.3 grams/litre soluble copper from a 4 per cent w/v suspension in 100 days at 32°C.Solvent extraction recovery of soluble copper is recommended as a final step in a leaching process.

Jan 1, 1983

By S. J. Jung

The most frequent causes of accidental injury and fatality are carelessness and ignorance; and the most common accidents are haulage accidents, fall, drowning, and fire. However, in this modern day and age, severe injury has become the dire consequence of an ever-increasing number of industrial and mining accidents as well as sport-, military- , etc. Mine accidents have declined dramatically in number and severity through decades of research, technology, and preventive programs. However, preventing recurrence of disasters like those of the past remains a top priority requiring constant vigilance by management, labor, and government. The goal of the present research is to investigate and identify root causes associated with types of mining accidents (victim being caught by an equipment, bodily motion, over exertion, etc) and nature of injuries such as (sprain and strains, fracture, dislocation, amputation, etc). Further, we hope to discover the impetus of the root causes occurring more and more often in this modern day of technology and quality awareness. With the different dimensions of accidents and injuries brought into the fold, there is the need for researchers and mining operators to comprehend and better still visualize significant patterns of associations among these variables of interest. We assume that, there is a high correlation between many dimensions of nature of injuries and types of accidents. This suggested a principal component analysis to reduce the dimensions for easy and amenable interpretation.

Jan 1, 2012