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By Herbert H. Einstein

Rock mass deformability is commonly predicted using correlations with RQD or other indices of rock mass quality, or by extrapolation from large in-situ tests. Based on the probabilistic description of rock masses empirically developed in Part I a new approach was attempted in modeling for predictions of deformability. This approach decomposes the rock mass into spatially variable joints described by probability distributions, and intact rock blocks. Stiffnesses and elastic parameters are associated with the joints and intact blocks respectively, and deformations built up by adding the contributions of each. This model allows relaxation of many of the simplistic geometric assumptions which constrain parallel attempts to model deformation in rock masses. The model has been applied to four standard cases in order to test its results against previously existing models, and to check whether it replicates empirical correlations. When joints are taken as parallel, common empirical correlations are closely approximated by the model output. However, the closeness to empirical correlation breaks down when variability of the jointing geometry is increased.

Jan 1, 1979

By A. J. Farstad

Characteristics of metal/non metal mines were evaluated to determine the suitability of applying the U.S. Bureau of Mines electromagnetic location system to the problem of locating trapped mines in metal/non metal mines. Statistical distributions of mine depths and overburden conductivities show that the existing USBM EM system is inadequate for most metal/non metal mines. Alternate approaches to trapped miner location in deep mines were identified and subsequent field tests were conducted at six (6) mines to evaluate their feasibility. The approach considered to be the most promising is one which utilizes the existing manpack transmitting system, modified slightly for a dual frequency output, in conjunction with a sophisticated signal processing receiver on the surface. The main advantage of staying with a "through the earth" approach is that the underground equipment can be kept simple, easily maintained, light-weight and inexpensive.

Jan 1, 1979

By James P. Ludwig

This report provides the results of a two year study of the projected time and cost requirements for new mine development in Wisconsin and is based on a unique blend of information from mining company officials, state regulatory agency officials and contractor experience. Through formal cooperative and review agreements with Kennecott Copy per Corporation, Exxon Minerals Co., U.S.A. and Noranda Mines Ltd., and the Wisconsin Department of Natural Resources plus informal arrangements with knowledgeable Wisconsin persons, lists of the tasks and subtasks required to plan a new mine in Wisconsin were developed. Times and costs were assigned to all tasks and subtasks and these data reviewed by all cooperators. Critical Path Method Diagrams were then developed for a generalized mining project. Total time and cost for the premine planning process was estimated to be 25..1 years and 223 person-years of professional time excluding public affairs effort respectively. By eliminating redundancies in the process and by increasing project efficiency through early public review and participation, recom¬mendations were made to lessen the time and lower the cost of premine planning. The streamlining recommendations could shorten the overall critical path length to 18.16 years and lower the cost to 208 person-years of professional time excluding public affairs effort. The estimated distribution of professional effort (cost) for mine planning in Wisconsin approximates 50.5% for traditional mine engineering tasks, 36.6% for environmental-regulatory tasks and 12.9% for traditional geological-exploration tasks.

Jan 1, 1979

By Jack L. Woodward

The evolution of surface mining equipment has resulted in larger, faster haulage units, loaders, etc., resulting in increased demands on steering technology. Careful analysis of these systems was warranted to determine if steering-related safety problems have been introduced. The objectives of this program were to: 1. Define the generic types of steering systems being used on mobile mining equipment used in surface mining operations. 2. Gather information on steering-related accidents in mining operations. 3. Assess the need for initiating government-sponsored research into steering system technology. A comprehensive literature survey was conducted concurrent with extensive contacts with mining operations, mining equipment manufacturers, steering system component manufacturers, and government agencies. A Technical Evaluation Group composed of representatives from the above organizations was formed to review the data gathered. It was concluded that the steering systems in use on surface mining equipment are reliable and do not present a safety problem. The Society of Automotive Engineers, Inc. is active in pre-paring voluntary consensus standards to assure that the minimum levels of performance are defined for industry.

Jan 1, 1979

By James R. Boyle

The value of mineral production increased 6.2% in 1976. With the exception of coal, practically all commodities registered an increase in production and value; most had an increase in unit value. Total value exceeded $1 billion for the first time. The increase in nearly all nonmetallic mineral production was a complete reversal of the 1975 experience. Alabama led the Nation in the production of crushed marble and was second in bauxite and scrap mica, third in oystershell, third in kaolin, and fifth in dimension limes-tone and dimension marble. International Trade.-The international trade passing through the Mobile customs district was valued at $2,524 minion in fiscal year 1976, up 20% from that of the previous year. Of the total value of trade passing through the district, 52% of the value of experts and 89% of the value of imports were handled through the port at Mobile. The major export Commodity was coal through McDuffie Coal Terminal which amounted to nearly 2.9 million tons, up from 2.4 million tons in 1975. Coal exports were to Japan, Italy, Turkey, the United Kingdom, and Brazil. Other exports were cement (114,000 tons) and [ ]

Jan 1, 1979

By W. Hermanson

This report presents the results of a task to complete a final design of a remote controlled hi-roof bolting machine for high roof areas in coal mines. The project was begun by visiting several coal mines to become familiar with roof fall areas. Several machine concepts were generated and presented to the design committee for criticism. A preliminary design was completed, as covered by this report. A Final Design and Final Report will be issued incorporating the committee comments at the Preliminary Design review and comments received concerning this Preliminary Design Report.

Jan 1, 1979

This study assesses whether Narragansett Basin coal deposits could be developed commercially in the near future. To do this, we identify the potential market for the coal, assess the price these users would be willing to pay for Narragansett coal, and this price to the expected costs of producing Narragansett coal. The study concludes that the major market, New England utilities, could burn bituminous coal from Pennsylvania or West Virginia at a lower total cost than Narragansett Basin coal, assuming expected mining conditions and emission policies. Therefore, the study concludes that Narragansett Basin coal resources could not be developed economically in the next ten years.

Jan 1, 1979

Recommendations from 44 mining industry workshops are summarized and reviewed in the context of Bureau of Mines research and development programs on-going during the period 1974-1977. Approximately 1,000 specific recommendations for research and development are summarized in a systematic and comprehensive format appropriate for review by mining research and development program managers. Relevant Bureau of Mines research programs are briefly described and some opportunities for future research and development are identified.

Jan 1, 1979

By J. A. Kosek

Work has been conducted under Bureau of Mines Contract Number HO 357078 to develop instruments for detecting CO, NO and NO2 in a mine atmosphere, using fuel cell technology. The approach has been to optimize the fuel cell sensor configuration for the specific detection of CO, NO and NO2 in the presence of other mine gases utilizing recent advances in catalyst, electrode and solid polymer electrolyte membrane technology. Para-metric testing has been conducted on three electrode sensor cells to define performance and life characteristics as a function of temperature, feed flow and applied sensor voltage. Extended life testing has been performed on sensor cell configurations exhibiting favorable characteristics. Reliable, efficient gas sampling and electronic control circuitry has been fabricated for use with the sensor cells, and integrated into devices to meet the performance and design specifications for portable, battery-powered, hand held direct indicating gas detectors for use underground. Twenty of the production-type, direct indicating CO detectors have been tested and delivered to the Bureau of Mines under the present contract. Three prototype diffusion head CO monitors have also been delivered for evaluation under the pre-sent contract. The gas sampling pump and related parts have been replaced by a diffusion tube assembly in which CO reaches the sensing electrode surface by diffusion alone. In addition, delivery will be made of ten direct-indicating nitric oxide detectors and ten direct-indicating nitrogen dioxide detectors. These instruments are very similar in design to the direct indicating CO detector.

Jan 1, 1979

By Ralph B. Stevens

The objective of this 20-month program was to define the relationships between mine ventilation, temperature, humidity, ore properties, material's used in mine operations, etc., and the spontaneous combustion problem in underground metal mines. Tradeoff studies of availability, reliability, cost, and maintenance of spontaneous combustion protection sensors and telemetry were conducted, after which a prototype system was selected from four design alternatives. This selected system was then laboratory tested and demonstrated in an underground copper mine.

Jan 1, 1979

By Clifford B. Farris

The natural cementation strength of retorted oil shale is the focus of this investigation. The optimum retorting temperature and residence time to obtain natural cementation strength in retorted Green River oil shale from western Colorado were determined as follows: [Optimum Conditions for Natural Cementation Maximum Residence Obtained Retorting Time at Compressive Mode of Temperature Temperature Strength' Retorting °F °C hr psikg/cm-2 Direct 1,520 822 2.0 270 19.0 Indirect 1,530 832 2.9 325 22.8] 1 Scattered samples were tested at strengths as high as 463 psi (32.6 k /cm 2) (Run 8, indirect mode) and 406 psi (28.5 kg/cm2) (Run 48, direct mode), but these high strengths were not confirmed by nearby tests. Minus 0.5-inch (1.3-cm) Green River oil shale was heated in a differential retort under conditions simulating potential full-scale retorting processes. The variables investigated were retorting temperature, residence time, retorting mode, and shale grade. Samples of the retorted Green River oil shale were moistened to optimum plus 2% (25%) moisture, compacted to 95% Proctor density, sealed and cured at 100°F (38° C) for up to 40 days. Lower curing temperatures, which are likely in the field, would probably result in significantly slower development of cementation strength, and might lower the ultimate strength developed. However, these effects were not studied in this project. The cured samples were tested for compressive strength, and correlative equations were developed for the increase of compressive strength with curing time as a function of retorting temperatures and residence time. Petrographic analysis indicated that the cementing mechanisms may be the interlocking growth of acicular hydrated calcium aluminum sulfate crystals between the contacts of retorted shale fragments. Samples of the retorted shale were also tested for optimum Proctor density and moisture. Permeability and quality of the leachate of shale from typical runs were determined. The effect of use of retort rather than tap water on compressive strength and leachate after curing was determined. The retorted shale effectively filtered several mineral constituents from the retort water.

Jan 1, 1979

By H. D. Raymond

This report contains a summary of designs, specifications, costs, and schedules developed for a prototype oil-shale demonstration mining program to be undertaken at the Horse Draw site in the Piceance Creek Basin, Rio Blanco County, Colorado. The objective of the demonstration program is to assess the feasibility of extracting oil shale and associated saline minerals from deep, rich oil shale zones which occur within the central portion of the Basin. Four mining systems were specified for demonstration. These include (1) chamber and pillar mining with backfill; (2) sublevel stoping with backfill; (3) sublevel stoping with full subsidence; and (4) block caving. Commercial-scale designs for each system were modified and scaled down as required to achieve program objectives. The demonstration mine layout and design includes specifications for ore handling, backfilling, ventilation, dewatering, maintenance, and supply systems. A feature of particular interest in the design is the combination of block caving and sublevel stoping methods into a single unit for demonstration of subsidence mining systems in deep oil shale deposits. The report also contains a detailed breakdown of projected capital and operating costs for the demonstration mining program.

Jan 1, 1979

By Dhanesh Chandra

[The U.S. Ucparunent of tlIe III LeriOr, Bureau of 1?Ilnes, lnta dcvcltil- (I a m.?tl,nd to extract nickel, i:ob.tll and IlIIicr Valuc:l,1, mrl?tl., lrom I.ow grad:, dumusI it Inlet itc.: :isin;; a rarb-i mnnnxid:: reducl.iun and ,innnonln/mumonlum sull,h.Ito Icitcll Col lowed by solved. evil let foil and clot tr:,winnfu,;. 'I 'o rain bcLtur undcI'sLandin;; uI the producLs reduced rind leached with the s;:Item, the liureau of t?Ilite; was enf,ngod In a 1 uinL sl.utly IIt1I the Uuttvcr ltc~:c:n-ch LnstiI-IL-. 'I'hr'ut;;h C(Im:drlod ahplit I¬L ion:; of a rotnbIW)L11nl ill eleu Lyon :utJ uplical inicrnscopy, cle trun beau micru,inal?;st?s and X-r.iv tcchnitlaes, Lhc factors jilt] ucncing low nickul e::lracl.on yLrids Iron, ccrlnin l;tteritos wul the hcuefhe al yCferL front addil.I:un u1. r:u)plowt' ruug,ounus and halides have bucn rrvealod. IL leas ht'en shown their nt nliJcrate Lion terlperuLuri's (5S0°C - 6501C) Lhe 111LACl extraction ylolds were low hccausc of the futmetlt-m of rufrill t,urv sillc:Ite compicxcs during ciii lit Hi [hut COOL.tlu sig nlficnnt anutunls of nickel .Lrui LhaL arc resistant Lu discolullull it, a su6r.C?quent ammnnlIca1 Jcaeh. 'This formation ill rulracLorv rnngtieves is altrlbuU?d Lo the prc.srnCV of aluauinum combined with c.ilicun jn addlt.lon In tnnl;neni~im in I.lic Lalerites, Iligb exII.Ictlon yields were oblalneJ when none or only a few I ,fraCLot' e, were InrmeJ. Hit s;intc rcfrarlnry cowl, Icxc5 also lend Lo surround Ow IaaIIiable meI.allle iron-IIIcI:el :iILoy CIUSisling ill the mau'ix, tIll: rrhv nreveu)Ling cuntacr ,Itlt LI5U Jeacl: solution; this, huwrvcr, ran ho ovu:rcoml by At ti itlon .111.11 retieCtiun. 'I'hc eIIcc l of prr.reJIctlun .,Ill itivi's vucli i's lye iii', ',udlum "Ill orIde, hv,Irogrn CIIInrILIC, etc., and Lht? 1111,Lre:InrLlI'll he'e:tleg un Lbe cxLt,icLitin are also iilsr.ussod 111 Lhe rcl,olt.]

Jan 1, 1979

This document is Volume II of a two-volume report on underground and surface coal mine fires occurring between 1950 and 1977. Volume I discusses the methods of data acquisition, data analysis procedures, results and conclusions. This volume contains (1) a master list of all fire incidents obtained from MSHA reports, (2) an annotated bibliography of all MSHA reports, journal articles on selected incidents, and non-reportable fires (appendix), and (3) indexes to be used in accessing incidents in the master list and annotated bibliography. These three types of information provide the reader with a complete summary of coal mine fires during the period from 1950 through 1977 and a convenient means to locate incidents of specific interest. The body of this volume is organized around two tables and a series of indexes. The two tables are master lists of underground and surface fire incidents. They are followed by 14 indexes keyed to the master list and annotated bibliography. The appendix contains three different parts: o The annotated bibliography of MSHA fire reports (one section each for underground and surface mine fires) o The annotated bibliography of journal articles about selected fires from the MSHA bibliography o A listing of non-reportable fires (one section each for underground and surface mine fires) Descriptions of the contents and use of each of the three major components of this volume (i.e., master list, indexes, and appendix) are presented in Section 2.0.

Jan 1, 1979

By G. B. Clark

One portion of this project was to test a blast shield and to design some features for a novel tunneling method termed the Automated Drill and Blast System (ADBS). The ADBS tunneling concept was developed for the design of an excavation system of greater efficiency than conventional drill, blast, and muck (DBM) systems by minimizing the down time and approaching the non-cyclic efficiency of continuous tunneling by means of small charge blasting. Small charge blasting uses simultaneously detonated, small light charges (less than 200 grams per hole) in four to eight shallow (24 to 36 in. deep) holes usually in a line. Limitation of the total explosive per blast reduced air blast overpressure, fly rock velocity, vibration, and noise. Thus, shielded equipment can remain at the face and a tunnel shield permits support personnel to work outby the shield at all times. The ADBS equipment will be composed of five components: (1) a chassis, upon which is mounted automated mucking equipment, and a frame which carries (2) the hydraulic drill(s), (3) load/blast system(s), and (4) control cab(s). The blast shield may have its own mounting. Ventilation, horizontal, and vertical alignment controls are incorporated in the system. The blast sheild, which protects personnel outby the advance equipment from air blast overpressure, fly rock, and gases, was tested with full scale small charge blasting. A blast shield was designed, fabricated, and tested under conditions anticipated for a working model. The shield was designed to expand to fit the tunnel shape, to seal itself to the tunnel periphery, and to contain air blast, fly rock, and gaseous explosion products. In addition, the shield, which was lined on the inby side with rubber belting, reduced the blast noise level outby the shield to 113 dBA or less, which is very near permissible levels. The test results show conclusively that the shield concept is viable. Based partially on the shield tests, a blast resistant control cab was designed to be located on the equipment chassis inby the blast shield to protect operators during blasting, and to contain all the controls necessary for system operation and safety. The economics of tunnel driving using the ADBS were compared with those of DBM. Four rock types, which determine advance rate, and four cost categories were examined. The results of this analysis are as follows: 1. ADBS advance rate is faster because equipment remains at the face and operation procedes semi-continuously. 2. ADBS bit and explosive cost (which accounts for 4%o of the total advance cost) is higher than for DBM. 3. ADBS equipment cost, on a per foot basis, is lower than for DBM. 4. Due to a reduced labor force, ADBS labor cost is lower than for DBM. 5. Because of the overbreak reduction due to controlled blasting, ADBS tunnel support cost is lower than for DBM. 6. On a per foot basis, total ADBS advance cost is from 17% to 20% lower than for DBM, depending on tunnel diameter and rock type. The small charge method greatly reduces ground vibration, increases personnel safety by limiting excessive fracture, and decreases tunnel support requirements by reducing overbreak. The overall analysis, tests, and results to date show that the Automated Drill and Blast System may be developed into a viable tunnel excavation method. The method also may be adapted to use in the mining of ore. For some types of mining operations, the cyclic nature of conventional drill and blast methods may not be a disadvantage, either where the drilling and mucking may proceed simultaneously or where the operations are carried out in adjacent working faces. The proposed method would find application where continuous methods of excavation are desirable.

Jan 1, 1979

By Walter W. Kaufman

This report summarizes a study conducted to determine the state of the art of various rock removal systems and their capabilities. The objective of the study was to determine if currently manufactured equipment can adequately accomplish rock removal in surface mine reclamation applications. Evaluations of state reclamation regulations, with regard to topsoil rock content, were made to determine the rock removal requirements. The major categories of equipment studied are rock pickers and rock rakes. The impact of rock removal implementation on the reclamation operations is discussed in detail.

Jan 1, 1979

1. Domestic Production and Use: In 1978, 12 companies operated 31 primary aluminum reduction plants, with 3 firms accounting for 65% of production capacity. Washington, Oregon, and Montana accounted for 31% of the total capacity; Gulf Coast States 23%; Northern States 26%; and other Southern States 20%. Based on published producer prices, output of primary metal in 1978 was valued at $5 billion. Aluminum consumption by 25,000 firms was centered in the East Central United States. Of aluminum consuming industries in 1978, building accounted for about 25%; packaging 22%; transportation 23%; electrical 11%; consumer durables 8%; and other uses 11%.

Jan 1, 1979

By J. A. Kost

Contract H0242013 was originally to evaluate through underground tests, water spray systems for controlling respirable dust at the face of a longwall plow. A number of difficulties were encountered which made such an evaluation impractical. The contract was modified to evaluate, in the BCR dust tunnel facility, the live factors believed to affect respirable dust levels. A 60-foot long; plow face mock-up was constructed in the dust tunnel, a facility with controlled airflow and dust concentration. Six types of nozzles were tested with the following parameters: two nozzle orientations, two levels of water pressure, two levels of airflow, and with and without simulated airflow through the gob. Of these factors, the most significant in reducing respirable dust levels was nozzle orientation, where the nozzle directed 45 degrees downstream resulted in 27 percent lower dust levels than those directed 45 degrees upstream (against the airflow). Following in order of effectiveness were the higher water pressure and the lower airflow. All nozzles tested resulted in similar dust reduction, i.e., the type of nozzle was the least significant factor.

Jan 1, 1979

By John Kosek

The electrochemistry of carbon monoxide, nitric oxide and nitrogen dioxide was investigated at a variety of electrode materials in different supporting electrolytes. A portable detector for carbon monoxide was developed using a porous gold anode in perchloric acid supporting electrolyte. This detector has two full scale ranges, 0-100 ppm and 0-500 ppm. A portable detector for mixtures of nitric oxide and nitrogen dioxide was developed using a porous silver cathode in sulfuric acid supporting electrolyte. Nitrogen dioxide was determined in the gas stream by electroreduction. The nitric oxide in the gas stream was oxidized to nitrogen dioxide by passing it over Cr(VI) on firebrick. Electroreduction gave the sum of NO + N02. Analog circuitry was used to display the amounts of NO and N02 separately. Two ranges were available for each gas. They were 0-10 and 0-50 ppm for NO and 0-2 and 0-10 ppm for N02.

Jan 1, 1979

By Glenn Adkins

This report characterizes pivoting joints in the structures of mining machinery and how the wear on the various components, i.e., pins, lugs, yokes and bushings, may affect the safety of mine personnel where these components are allowed to wear excessively before repair or replacement.

Jan 1, 1979