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By William Gleason

"It is safe to say that the coal industry, in the United States and globally, is currently suffering through one of the hardest times in its history.A perfect storm of competition, changing energy demands, politics and public perceptions have collided, inflicting significant harm to the industry that many say is irreparable. This, in turn, has led to massive job losses in some regions, heavy cuts in production and even bankruptcy filings from two of the largest coal mining companies in the nation.Cheaper natural gas can certainly take a large share of the blame for the struggle of coal, as utility companies switch from coal to natural gas for power generation. According to the U.S. Energy Information Administration (EIA) the amount of coal used for electricity generation in the United States is at a 45-year low.November 2015 marked the fifth consecutive month that natural gas was the leading source of power generation in the United States. EIA said generators produced 101,866 thousand megawatt hours (MWh) of electricity with gas in November versus just 87,789 thousand MWh with coal, the lowest monthly level since May 1980 when monthly coal use was 84,884 thousand MWh.According to Robert Godby, director of the Center for Energy Economics and Public Policy at the University of Wyoming, there are a number of factors playing a role in the decline of coal, but he points to the advances in fracking as the tipping point.“A lot of people will argue that regulation is the cause of the decline, and it has played a part, for sure, but the story of the recent past is more about what competition has done to the energy market,” Godby told Mining Engineering. “The war on coal was originally declared by natural gas in 2008.”The price of natural gas, which was at $13 per million Btu before the gas fracking boom, has fallen to as low as $1.68 in December 2015. Likewise, Godby said the cost of wind generation is now lower than the cost of generation from coal and the cost of solar generation is coming down as well. In addition to that, the demand for energy has changed in the past five years with more efficiencies in everything from building design to lightbulbs."

Jan 1, 2015

By Dermot M. Winters, Brent T. Wahlquist, C. Y. Chen

The enactment of the Surface Mining Control and Reclamation Act (SMCRA) in August 1977 addressed subsidence resulting from underground mines, in addition to creating the requirements for reclamation of surface coal mines. Subsidence control regulations pursuant to SMCRA were initially promulgated in March 1979. Several revisions have since been made. In addition, due to court challenges some regulations have been remanded and others are still on appeal. In the meantime the Secretary has agreed to initiate rulemaking on some issues. It is yet to be determined how the prohibition of certain areas from surface coal mining operations under Section 522(e) of the Act applies to subsidence. This presentation discusses the status of the regulations and issues related to or affecting the subsidence regulations.

Jan 1, 1986

By Tomás Vergara, Marcelo Vergara, Alonso Pereira, Fernando Concha, María V. Gutiérrez, Fernando Betancourt

Filtration of copper concentrates in the mining industry is carried out in cycles, mainly cake formation, expression, and blowing. Each of these cycles depends on the solid (mineralogy, porosity, particle size distribution), water, and air (density, viscosity, permeability, and relative permeability) properties that define the performance in each cycle. The fundamental phenomenon in cake formation and expression is a one-phase flow (water) through a porous bed of solid particles (the cake), while in blowing it is a two-phase flow (water and air) through the cake. Sometimes, due to a change in the properties of the mineral, a filtration plant is unable to maintain the capacity at the specified humidity. One alternative to solve this problem is to heat the air during the blowing cycle, which in turn heats the water in the cake, this process significantly decreases the water viscosity and only marginally increases the air viscosity. In this work, this strategy was studied at a laboratory scale. The results show a significant decrease in the blowing time as the temperature of the air was increased.

May 24, 2022

By J. Wickens

This paper discusses how Bald Mountain Mine dramatically reduced mercury production by treating process solutions with a liquid reagent called UNR 811A. The reagent is marketed by Cherokee Chemical Co., Inc. A summary of the bench tests comparing several different reagents is given. The ensuing plant trial is discussed and results are presented. The plant trial treatment costs are discussed. Finally, potential cost savings are discussed.

Jan 1, 2001

By J. R. Klaehn, M. Shi, T. E. Lister, L. A. Diaz, J. S. McNally

Since 2019, approximately two dozen international battery recycling companies have been operating at the commercial or pilot scale [1]. However, current process capacity does not exceed 100,000 tons of end-of-life (EOL) lithium-ion batteries (LIB) per year, and the current recycling rate is only about 5% in North America [2-3]. Recycling metals from EOL LIBs is not only essential to waste minimization and environmental stewardship, but also a source of critical materials, which can contribute towards supply chain stabilization. LIB recycling can be roughly divided into three categories: direct recycling, pyrometallurgy, and hydrometallurgy. Direct recycling seeks to retain as much of the manufactured effort with minimum chemical processing [4]. The evolution of battery designs and chemical compositions are challenges to this approach [5-6]. Pyrometallurgical processes are robust and flexible allowing a broad spectrum of batteries with minimum pre-processing requirements. Some of the matrix issues are solved through combustion of some constituents. Smelting is strongly tied to fossil energy and air emissions are a concern. In addition, pyrometallurgical processes are not stand alone, as hydrometallurgical refining normally required to separate and recover the metals of interest (Co, Ni, and Cu) from the produced alloy and Li from the slag [7]. Hydrometallurgical processes can be highly selective and efficient in recovering high purity materials [8]. In general, hydrometallurgical processes are considered cleaner and less costly than high temperature processes [4,9-10]. Extensive chemical consumption and waste generation significantly increase the operating costs and overall environmental impact of the hydrometallurgical processes [11]. Leaching of metals from LIBs is dominated by the mixture of sulfuric acid (1 to 4 M H2SO4) and hydrogen peroxide (1 to 15 wt.% H2O2) [10]. Although organic acids have been tested as lower environmental impact alternatives, the reported pulp density operations are low < 60 g/L [10-11]. For the H2SO4/H2O2 leachates, high leaching efficiencies >90% are reported for Co, Ni, Mn, and Li from cathode materials at temperatures over 40 ⁰C and pulp densities between 30 to 200 g/L [9-10]. H2O2 acts as reducing agent to convert Co+3 and Mn+4 into their soluble forms, Co+2 and Mn+2 [12]. Despite the claims of H2O2 being a clean reducing agent [13], production of H2O2 has significant environmental impacts as determined by life-cycle analyses [13-14]. Moreover, the costs and risks associated with H2O2 transportation and storage cannot be ignored [15].

Mar 2, 2022

By T. Geyer

The Carbon Disclosure Project (the pre-eminent global initiative for institutional investor collaboration on climate change) groups the business risks (and opportunities) related to climate change into four categories: 1. Regulatory risks from tightening legislation (and opportunities for companies that can make the carbon market work for them), e.g. rising costs for carbon and energy-intensive processes. 2. Competitive risks & opportunities generated by a possible decline in customer demand for carbon/energy intensive products (and opportunities from a consequent rise in demand for efficient / low carbon products). 3. Reputational risks from perceived inaction on climate change (and benefits to those perceived to be ?solutions providers?). 4. Physical risks from changes to climatic patterns, e.g. asset damage from extreme weather events; project delays; water scarcity; resource risks as certain crops become no longer viable in certain areas and new supply chains become necessary; and potential human and socio-political impacts. All of these are already having repercussions for businesses in certain sectors and geographies. The understanding of specific impacts of climate change is still evolving but it is clear that climate change will have a material impact on the value of many businesses, either directly or indirectly. Many commentators and analysts consider that rising energy costs are likely to represent the most direct and immediate investment risk that climate change and the resulting regulatory responses will create for business in the near term. However, it is already possible to identify numerous examples of competitive and reputational risks and opportunities that are leading to significant value creation or destruction in business: the success of the Toyota Prius; the rush by the UK?s leading supermarket retailers to ?green? their brands; and the surging fortunes of companies involved in the manufacture of renewable energy generation equipment, are all manifestations of this trend. In addition, the potential physical impacts of climate change are also making themselves felt in certain sectors: an example is the Australian wine industry, suffering after an extreme and prolonged period of drought. THE PROJECT This paper describes a project undertaken for a multinational mining company to examine the physical risks from climate change across its international business operations. The study addressed 163 components of the business and included operating sites (mines, smelters, and refineries), key transport routes (road and rail) and port links. The inclusion of the transport networks and ports is extremely important; key transport routes (e.g. a key railway link) may often be impacted (e.g. by flooding) far more than individual sites due to their large geographic exposure and multiple potential failure points. Extreme weather events causing loss of life and major economic damage continue to be front page news. According to the World Meteorological Organization, January to July 2007 ?was marked by record weather extremes in many regions across the world.? Inevitably, the associated phenomena are starting to impact business and investments, not so much as deal breakers, but in changing the parameters of risk management and the approaches required to devise mitigation measures. EXAMPLES OF EXTREME WEATHER EVENTS No one event can be presented as directly attributable evidence of climate change, however climate change projections suggest that the frequency and severity of many extreme weather events can be expected to increase in a warming world. In August 2003, a heat wave struck Europe, with temperatures as high as 42°C (108°F). As summer temperatures in much of northern Europe rarely exceed 30°C (86°F), the area was unprepared for the disaster, and many thousands of deaths occurred. In August 2005, Hurricane Katrina caused catastrophic damage along the Gulf Coast of the United States, forcing the effective abandonment of south-eastern Louisiana (including New Orleans) for up to two months and damaging oil wells that resulted in increased oil prices. Katrina killed over 1,800 people and caused at least $75 billion in damages, making it one of the costliest natural disasters of all time. This was followed in September, by Hurricane Rita which left 119 people dead along the U.S. Gulf Coast, causing $9.4 billion in damage. In January 2006, hundreds of people were killed when Russia, Eastern Europe and Scandinavia experienced the coldest weather for decades. In summer 2007, dramatic floods in the south central region of England, UK left 350,000 people without drinking water and many without electricity. Transport infrastructure was severely disrupted; combined with floods which occurred earlier in the summer in Yorkshire (North England), the damage is estimated to total over £2 billion. ASSESSING RISKS FROM CLIMATE CHANGE To date, only a minority of companies have attempted to quantify the risks from climate change. However, investors are seeking greater disclosure of climate change related risks and opportunities and it is expected companies that can demonstrate they are prepared for climate change will attract higher market valuations. Climate Change Threats A variety of climate change threats were examined for their potential to have a potential measurable impact on the mining company?s business operations. Those considered most significant were included in the study and are shown in Table 1 (see Appendix A). Certain threats can be considered as being cyclical in nature and the future predictions may suggest a change in the frequency and severity of such events (e.g. storms/hurricanes, rainfall, drought). However other threats are associated with a gradual change over time (e.g. loss of glaciers, loss of permafrost, sea level rises). A slightly different approach is needed to address this differing nature of the threats, as described subsequently. Climatic Regions Much of the research and data associated with climate change is collected and reported on a regional basis. An example of the climate change impacts predicted for a number of climatic regions is shown in Table 2 (see Appendix A).

Jan 1, 2009

By Connor Langford, Murray Gant, Ken Massé

For public organizations, preparing accurate project cost estimates is a critical component in capital project planning. Project delivery methods provide a structured approach to moving projects through the design and construction lifecycle, and typically use cost estimates as key inputs at each stage to determine if the project will advance. As design stages can occur years or even decades before construction contracts are awarded, estimates need to make reasonable assumptions about how the work may be executed (means and methods) as well as potential future market trends so that appropriate values for material pricing, labour costs, escalation, and owner’s costs can be included. This process is challenging enough during stable markets, as historic trends can often be misleading and require a suitable understanding of economic factors to use appropriately. When you mix in the market volatility that has been observed since 2020, developing accurate project cost estimates becomes even more challenging. In cases such as this, having a structured approach to cost estimating that includes an adequate risk-based reserves cannot be overstated as it provides the basis for ongoing project decisions. This paper explores some of the historic and more recent market trends that have impacted key aspects of project cost estimates for capital project planning. It also provides recommendations on how to develop cost estimates for infrastructure projects, with examples from Metro Vancouver, which plans for and delivers regional-scale services to 2.6 million residents. A brief commentary on the use of escalation clauses in contracts is also presented.

Jun 13, 2023

By August E. Vandale

I speak to you today on the subject assigned to me, "Subsidence - a Real or Imaginary Problem", as a representative of Consolidation Coal Company (a wholly owned subsidiary of Continental Oil Company). The information I relate to you is our experience in the Pittsburgh Coal Company Division of Consol and covers the Pennsylvania properties and mines with particular emphasis on the mines in the south- western portion of the State or in the immediate vicinity of Pittsburgh, Pa. Mining of Freeport and Pittsburgh seams of coal in the Pittsburgh vicinity dates back over one hundred years. Consol, or its predecessor, Pittsburgh Coal Company, has been actively engaged in mining in the area since Pittsburgh Coal Company was organized in 1900. Pittsburgh, Pennsylvania came into prominence as the Steel City largely because of the vast reserves of high grade metallurgical coal readily available in the immediate vicinity and also because of its favorable river transportation. Early in the 1900&apos;s we operated over 100 small coal mines, with operations located in the Counties of Allegheny, Fayette, Washington, Westmoreland. We have also operated mines in Somerset and Greene Counties. Titles in Pennsylvania can be in three estates: (1) title in fee, (2) title to the mineral, (3) mining rights permitting the removal and extraction of the mineral with or without waiver of surface damage. Consol has over the years acquired good legal title to the coal lands purchased from individual farm owners, with good broad mining rights, and in 98% or more of its title has a complete waiver of surface damage or the right to subside the surface land. In the early days of our Company, individual coal farms were purchased from land owners. Many of these titles severed the coal estate from the in fee title and good mining rights with waiver of surface were conveyed in the original severance deed. Thus, minable coal reserves were put together by the purchase of the coal under many individual farms in an area. In the early years, the mines practiced hand dug mining - later going to mechanical cutting with hand loading of the coal. Systems used were entry driving with room and rib panels. We have practiced full recovery mining as far as practical during the years of hand loading, as well as in the later years when the mines were mechanized. Mining system layouts, methods and procedures have changed from time to time to keep pace with improved mining machinery and new inovations, such as roof bolting and rubber tired haulage.

Jan 1, 1967

By D. J. Turk

Stillwater Mining Company’s, Nye Operation has been producing PGM concentrate since 1987.Several expansions have allowed for increasing capacity from the initial rate of 500 tons per day, to its present capacity of 3,000 tons per day. The expansions were performed with minimal impact upon production and maximum utilization of the existing equipment. The latest expansion incorporates a 6’ X 18’ SAG mill, 13’ X 20’ Ball mill, pebble crusher, rougher flotation cells, 1250 Hp tertiary grinding mill, middling and scavenger flotation cells, and cleaner column flotation cells. This paper will describe the concentrator flow sheet, and controls for improved concentrator performance.

Jan 1, 2000

By J. K. Lemley

The human element in large measure dictates success in contracting relationships. Because of our professional backgrounds, we view contracts primarily as either engineers, contractors or owners. A beneficial contractual environment--one in which decisions, risks and benefits are shared--demands equal consideration of all three points of view. Most of the older cities in the United States, for example, suffer from bad contracts--generalized, patched-together documents that represent an accumulation of modifications originally written to compensate for specific situations that have occurred over the years. Because such documents lack coherence, they often present conflicting instructions which lead to defensive, ultimately destructive attitudes among the parties involved in the day-to-day administration of the project. Good contract development begins with a strong central philosophy to which the details of the contract can be related. First, the owner should establish a comprehensive philosophy in which risks between the parties are identified. Following this, a specific contract document can be written to satisfy this established philosophy. The contrast between two opposed contractual situations, NYC Water Tunnel Number Three and the Seabrook Nuclear Power Plant Cooling Water Tunnels, illustrates how comprehensive, well-written contracts--contracts which share both risks and benefits--provide the basis for achieving quality construction that will reward engineer, contractor and owner.

Jan 1, 1983

By E. M. Spokes

A.B. Rushton The work and resulting publications of the Committee on Underground Coal Mine Safety and The President&apos;s Commission on Coal were appropriate at the time of publication. The statistics cited in the publications appeared to be valid, and the actions proposed by the committee had merit. Although the actions proposed to achieve further improvements in safety may have been worthy of repeating, to associate statistics (Table 1) that are seven to eight years old with company names is bad. Statistics are readily available from the Mine Safety and Health Administration (MSHA) and are usually within three months of being up to date. A review of the most recent Coal Controlling Co. Report will reveal significant changes in the rankings. The more recent statistics should have been cited, or at least compared with those used in the article. Westmoreland Coal Co. is listed as having a 21.1 disabling injury rate for the period (1/78-12/80). The disabling injury rate for the Company for the year ending 1985 was 7.4 for the underground mines and 6.25 for the total facilities. Through March 1986, the disabling rate for the underground mines was 2.86. The management and employees of Westmoreland Coal Co. are committed to safety. The improvements achieved over the past five years attest to that commitment. We are justifiably proud of the achievement and dislike being misrepresented as in the April 1986 article. Reply by E.M. Spokes I regret that the lapse of time since the original work gives a picture of safety practice that is no longer true today. That Westmoreland has reduced its disabling injury rate by 65% to 7.4 in 1985 is most commendable, and I congratulate you for this accomplishment. It is typical of the progress sought by the National Academy of Science and National Research Council when they funded the original study and published "Toward Safer Underground Coal Mines" in 1982. If a significant number of companies do as well as Westmoreland, the report will have served its purpose. Since the paper was primarily a condensation of the original report, it would not have been appropriate to seek access to later statistics. The purpose in seeking its publication at the time of presentation was to reach those who might have missed the original report. The fact that publication was delayed has not voided that purpose and may have reminded some who were aware of the original that its recommendations still apply to improvement of underground coal mine safety.

Jan 6, 1986

By J. Humphrey

Introduction The weight of a Mining Truck can be affected by field modifications, the selection of items like tires, rims or even the conditions in which it operates. Truck performance and the compliance with a number of ISO standards, e.g. braking, steering and ROPS are dependent on truck weight. It is critical that truck owners understand the impact of changes in weight1. What makes this even more difficult for owners to evaluate is that there is no standard terminology or definitions for Mining Truck weights. This paper discusses and defines weight terminology, how it applies to performance and standards and the impact on the application of Mining Trucks.

Jan 1, 2007

By T. Tamagawa

A gaseous chlorination process for hydrometallurgical treatment of a chalcopyrite concentrate was investigated. The overall process is visualized to consist of low temperature chlorination-selective oxidation, followed by aqueous chloride leaching and SX-EW for producing electrolytic copper, elemental sulfur and ferric oxide. In this article, the chlorination phase of the processes is described. Initially, the chlorination behavior of chalcopyrite-concentrate micro-pellets was investigated using a small batch-type fluidized bed reactor. The optimum conditions thereby established was used in continuous chlorination tests. The chlorinated products thus prepared were used in the selective oxidation phase of the investigation.

Jan 1, 1999

By J. M. Wempen

Booster fans in underground coal mines are often located using the concept of a neutral point. Normally, intake airways are maintained at higher absolute pressure than return airways, so air leaks from intake to return. By adding a significant pressure force to a region of a ventilation system, booster fans installed in a return airway can increase the pressure in the return so that air leaks from return to intake. This is commonly referred to as recirculation. The neutral point occurs at the location in the system where the pressure difference between the intake and the return airway(s) is zero and at this point there is no leakage or recirculation. Ideally, placing a booster fan near the neutral point minimizes leakage and recirculation; however, in practice the position of the neutral point is not static and it changes as the ventilation system parameters change. This paper presents a study of how changes in the system parameters affect the location of the neutral point in a model coal mine ventilation system. First the effects of booster fan pressure and location on the neutral point are evaluated. Next the effect of increasing mine distance, and therefore mine resistance, on the location of the neutral point and the magnitude of recirculation is evaluated.

Jan 1, 2012

By J. H. Schuenemeyer

Uncertainty estimates on coal resources were computed as part of the U.S. Geological Survey’s National Coal Resource Assessment study of more than 60 coal beds and zones in the Appalachian Basin, the Colorado Plateau, the Gulf Coast, the Illinois Basin, and the Northern Rocky Mountains and Great Plains. The estimates were made to provide zone specific measures of uncertainty on the historical categories of geological assurance, namely measured, indicated, inferred and hypothetical. Previous estimates were based solely upon distance from a drill hole. These new estimates incorporate site-specific variability and spatial correlation and indicate that there is considerable difference in variability within and between regions. Uncertainty estimates for the measured category are discussed in this paper.

Jan 1, 2001

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 Richard F. Coon

Six potential locations along the west shore of Lake Mead were evaluated to site anew water intake pumping station for the SNWA. The evaluations were based upon geotechnical exploration results and conceptual intake pumping station designs. The exploration included geologic mapping, geophysical testing, underwater ROV inspections and borings. Ground surface and underground chamber pumping station designs were considered. Sites at Saddle Island, Black Canyon and Hoover Dam are geotechnically suitable. A Saddle Island site was selected because it has the most favorable conditions for the intake pumping station and the aqueduct to the Las Vegas valley.

Jan 1, 1997

By D. J. Carpenter

Safe and successful mine closure represents a fundamental work element that needs to accommodate the geochemical conditions existing at the completion of the mining and ore processing effort. Given the interests in limiting costs and time associated with mine closure efforts enhanced prior understanding of the geochemical conditions likely to exist upon exhaustion of the economic reserves can provide important benefits. The purpose of this paper is to document the benefits associated with geochemical modeling and understanding how the ore formation process may impact mine closure efforts, using one ore deposit type as an example. Specifically, this paper will emphasize the geochemical processes leading to the formation of sandstone-hosted uranium roll-type deposits and how the resultant concentrations and distributions of ore and gangue phases need to be incorporated into understanding the geochemical conditions projected to exist at the end of mineral recovery efforts. The paper will describe the evolution of geochemical conditions leading to ore body formation and the geochemical effects induced by open pit mining and how these may be used to understand both the geochemical controls and constraints on residual mine water. In addition, a discussion will be provided on how these conditions may be simulated by solution equilibria and kinetic modeling to develop optimum approaches to achieve applicable closure standards. This paper will also discuss specific augmentations to existing industry standard solution equilibria and kinetic models and associated thermodynamic databases to maximize the predictive accuracy of the geochemical modeling results. The benefits of understanding the electrochemically reactive behavior of uranium and associated gangue phases and incorporating this behavior into mine closure efforts will be presented. The culmination of the benefits of the geochemical modeling will ultimately be the development of a sustainable approach to uranium mine closure that is based upon an engineered environment designed to return the ore body to stable geochemical conditions.

Feb 27, 2013

By R. J. Sweigard, R. V. Ramani

G.F. Learning The paper by R.V. Ramani and R.J. Sweigard is a wonderful description of the labyrinthine web that has been spun about the mining industry by energetic bureaucrats and politicians over the past 50 years. The remedy for the problem, however, is not more of the same, but less. That may be difficult for the industry to achieve, for it is not a technical solution but a political one. And the current fervor for more detailed planning at all levels of government and private enterprise has become deeply ingrained. The authors recommend the provision of more information about mining and mineral resources to "macro" (i.e., government) land use planners. They apparently overlook, however, the already strong tendency on the part of most government land use planners to consider themselves omniscient. Thus, giving them more information about the technical problems of mining will only make them want to get more and more involved in the "micro" (private, site specific) mine development and production plans of the individual mining firm. In fact, this has already happened at all levels of jurisdiction from municipal to federal government. Examples are legion. The most effective way to ameliorate the adverse impacts of government land use planning on existing and potential mining operations is to: (1) introduce greater flexibility in the definition of land use zones by local and state governments; (2) adopt realistic and relevant ambient environmental performance standards in governing relationships between mineral land uses and concurrent or subsequent nonmining land uses; (3) allow greater leeway for economic considerations in land use decisions in contrast to the explicit legalistic approach now in vogue; (4) recognize that all minerals are not the same and that sand and gravel mining should not be treated the same as underground metal mining, coal stripping, oil field production, or in situ leaching; and (5) eliminate the notion that mining operators should be responsible for determining in detail the use of land by subsequent owners of mined land. This last bit of conventional ethic really makes no more sense than requiring the builders of every shopping center or government office complex to provide detailed plans for the use of that land when its use for shopping or government is ended. Did the builder of Ebbetts Field plan for Brooklyn after the Dodgers went to Los Angeles? Should the developer of the Bingham Pit plan for suburban Salt Lake City after the copper mining goes to Chile? The nation&apos;s mining industry must address these questions before further bankrupting itself to provide more data to planners and spending thousands of dollars per acre to create land that when reclaimed is worth only a few hundred dollars per acre. Reply by R.V. Ramani and R.J. Sweigard We thank Mr. Leaming for his valuable contribution. His views on the problems of land use planning and mineral resources are most welcome additions to our paper. As the title indicates, our paper was more concerned with the impacts of land use planning on mineral resource conservation than with the details of the planning process. On the whole, his five recommendations would be helpful for mineral resource conservation. However, we would suggest that the argument he presents for his final recommendation does not address the differences between mining as a land use and commercial or institutional uses. We believe that this difference is the crux of the issue. We share Mr. Leaming&apos;s desire to ameliorate the adverse impacts of land use planning. Possibly the most detrimental impact is the loss of mineral resources. Any development, whether mineral or community, that does not give proper consideration to other resources can result in permanent loss or sterilization of resources. With proper planning, some of these losses can be avoided. As our paper indicated, one factor that limits the consideration of mineral resources, and ultimately leads to their sterilization, is the generally inadequate levels of resource characterization and understanding of the unique nature of mineral resources and mining operations. The last point raised by Mr. Leaming is also important. In terms of reclamation and land use planning in mining districts, we certainly do not advocate spending more than what the results are worth. The main thrust of the paper was to explore the avenues for conserving the mineral resources so that, at some appropriate time, the issue of mining and reclamation can still be addressed.

Jan 4, 1985

By Zoltan F. Oszter

The frictional resistance to motion of a belt conveyor has always been a subject of intensive studies and research by engineers throughout the years. Numerous informations have been developed by analysing series of field tests on belt conveyors of different characteristics and carrying different materials at various capacities. Within certain limits of weight per unit length and tension, the theoretical considerations and the analysis of the field tests, both in the US and abroad, resulted in the development of similar formulas. In general these formulas are safe to use up to the following limits:

Jan 1, 1977