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By C. P. Lazzara, Y. Miron, A. C. Smith

This report presents a U.S. Bureau of Mines study to identify the causes of self-heating events beneath the floor of a deep underground coal mine. Mine samples from both heated and unheated areas were examined by various techniques, including visual, microscopic, thermal, chemical, and instrumental tests. The combined results led to the conclusion that pyrite (FeS2) oxidation was the prime cause of the beatings. However, adiabatic oven tests of selected samples did not indicate the effect of the pyrite on the self-heating process, probably because of the experimental conditions. A fast, simple procedure to assess the concentration of pyrite in the mine samples was developed, utilizing the reactivity of the sample with an aqueous solution of hydrogen peroxide (H2O2)

Jan 1, 1992

By Louis W. Cope

INTRODUCTION Various methods for sampling placer deposits have been mentioned by Wojcik in Chapter 2. Here, a brief description and comparison of these methods will be given as related to bulk versus drill sampling. The advantages and disadvantages inherent to each will also be given. The means of sampling can be grouped into bulk or drill samples. As a generality, drill samples over a five-foot length will run from I/,, to 1 /, cubic yard, depending on the diameter of the drive shoe on the drill casing. Bulk samples can be expected to be in the range from one to many cubic yards each. SAMPLE METHODS Bulk Bulldozer-dug trenches and dozer or front-end loader pits are two methods to excavate large bulk samples. Smaller bulk samples can be obtained by digging small dimension shafts through the deposit, by hand or caisson-like drills. It is not recommended to split samples by alternate bucket-loads or by other means, as the effect of a nugget falling into one or the other fraction will seriously alter the sample.

Jan 1, 1992

By Doug Lockhart

The Marine Minerals Technology Center has taken advantage of recent price and performance .improvements in PC hardware and software to upgrade its seismic acquisition system. In the past, single channel, high resolution, seismic data was displayed on an analog plotter and stored on tape. Associated navigation data was logged by hand or on a chart plotter. The navigation and seismic data were synchronized with time so that they could be cross referenced. The Center's new system uses PC's for the acquisition of both seismic and navigation data. Off the shelf software products were purchased for each task. Elics Delphl performs the seismic acquisition and processing, and GeoResearch, Inc. Geolink provides the navigation interface. A navigation string is sent from the navigation PC to the seismic PC via an RS232 line. This string consists of a time and location fix, as well as speed and heading data. The navigation string is then imbedded in the header of the seismic record. The Geolink software is capable of monitoring other devices in addition to the GPS used for positioning. Device inputs are attributed to the location data to provide easy construction of a navigation GIs. Currently the Center is logging fathometer data along with the navigation. As a result, a map of bathymetry along the tracklines can be available shortly after completion of the cruise.

Jan 1, 1992

By P D. Katsabanis

"This chapter describes the principles for the derivation of the equations for a detonation wave.. Theimportance of the equation of state for the detonation products is demonstrated and commonly used equations of state are discussed. Furthermore a brief introduction to the TIGER code is presented."

Jan 1, 1992

Because surface mining removes the original plant cover from the land and exposes the soil, special care is needed. Until the mined land is stabilized by revegetation, snowmelt and rainfall can pick up sediment and erode mined lands much faster than undisturbed areas. Sediment control is an important aspect of protecting the environment during mining and reclamation because without it, large amounts of sediment can clog streams, increase the risk of flooding, damage irrigation systems, harm aquatic habitat, and limit the use of water for other purposes. Stream quality can be affected many miles downstream from the mine. Before SMCRA was implemented many streams were degraded by uncontrolled sediment from mining. Sediment is controlled through careful planning and a design that incorporates a variety of measures that work together to reduce soil erosion at the mine. Disturbed areas are graded, and some areas terraced, to achieve stable slopes, reduce runoff water velocity, increase infiltration, and divert runoff into drainage channels so that it flows away from unvegetated, erodible areas. Grading along the slope contour and scarify in gun vegetated slopes with bulldozer track marks help prevent erosion by slowing down the flow of water. Runoff from haul roads is controlled by culverts and roadside ditches. Sedimentation ponds or other forms of sediment control are required at all mines to minimize the amount of sediment leaving the site.

Jan 1, 1992

By Kurt Westerlund

The design of the economically most profitable and technically most feasible smelter process gas handling .and treatment as an integrated part of the total metallurgical process is discussed and exemplified, with alternative flow sheets including material and energy balances, investment and operating costs. Retrofitting and de-bottlenecking of existing gas handling lines will be described and exemplified. Methods of increasing total gas handling line availability will be described.

Jan 1, 1992

By Distin P. A

The extraction of platinum and rhodium from scrapped honeycomb autocatalyst into hydrochloric acid/aluminum chloride/nitric acid solutions is described. Results are given for the effects of leachant composition, temperature and catalyst pre-reduction using hydrogen. Data are also presented for the recovery, by hydrogen reduction, of platinum and rhodium dissolved in the leach solution. Parameters studied include solution composition and temperature, hydrogen pressure, and platinum seed addition.

Jan 1, 1992

By R. J. Reuss

Mina Maria is a high-grade, underground copper mine located in the Cananea district of Sonora, Mexico. The ore body is a massive sulfide breccia located in mountainous terrain. A major highway and an electric transmission line pass directly over the near-surface ore body. The mine is operated by Minera Maria SA de CV, a joint venture company that is 51 % owned by Empresas Frisco SA de CV and 49% by Cominco Resources International Ltd. Empresas Frisco is the operating partner. Production began in October 1990. The mining method used is undercut and fill. A continuous miner and a single-boom, hydraulic jumbo mine the ore. Backfill is a weakly cemented sand-gravel mixture that is pneumatically placed. The ore is treated by conventional crushing, milling and flotation. The Maria deposit is located about 40 km (25 miles) south of the Sonora-Arizona border and 11km (7 miles) northwest the city of Cananea and the Cananea Mine. The mine portal, at an elevation of 1780m (5840 ft), is on the east side of an important drainage divide. The mill site is situated about 800 m (2625 ft) northwest of the mine on the northwest side of the drainage divide where the drainage is more favorable. Its elevation is 1860 m (6100 ft) (Fig. 1).

Jan 1, 1992

By Art Hamilton

The Zn-Pb-Cu-Ag ore deposits of the Boundary and N-5 zones near Bathurst, New Brunswick, occur in a polydeforrned volcano-sedimentary sequence that is part of the Ordovician Tetagouche Group. Massive and disseminated sulfides are hosted by an argillaceous to cherty sedimentary sequence that is stratigraphically Wlderlain by a siliceous fragmental unit and is overlain by a feldspar-rich crystal tuff and related tuffaceous rocks. The deposits have a low iron sulfide content relative to that of most stratabound sulfide deposits of the Bathurst-Newcastle mining district. The ore is commonly associated with chlorite- and talc-rich sediments. The N-5 deposit is considered to be the fault-displaced extension of the Boundary deposit. The Boundary deposit is estimated to contain 891 000 t grading 3.31% Pb, 7.96% Zn, 0.32% Cu and 44 g/t Ag; the estimate for the N-5 zone is 330 000 t grading 3.24% Pb, 7.15% Zn, 0.33% Cu, and 37 g/t Ag. The ore is processed at 1000 tpd at the Heath Steele mill.

Jan 1, 1992

By F. Bourgeois, J. A. Herbst, R. P. King

The ultrafast load cell (UFLC) has proved to be an exceptionally good device for the study of the fundamental processes associated with the impact fracture of particulate material. A new high- sensitivity UFLC has been commissioned at the Utah Comminution Center for the study of low-impact energy single-particle fracture. The force-time histories of individual fracture events have been measured. The force and energy absorbed at crack initiation have been measured at several particle sizes. The mass specific energy for fracture and the associated breakage function have been determined. The distributions of particle breakage energy and particle strength have been measured as a function of particle size.

Jan 1, 1992

By Kurt Westerlund

The design of the economically most profitable and technically most feasible smelter process gas handing and treatment as an integrated part of the total metallurgical process is discussed and exemplified, with alternative flow sheets including material and energy balances, investment and operating costs. Retrofitting and de-bottlenecking of existing gas handling lines wil1 be described and exemplified. Methods of increasing total gas handling line availability will be described.

Jan 1, 1992

By André Vervoort

The roof behaviour in room and pillar panels during the development of roadways and the subsequent pillar extraction was monitored underground and numerical simulations were conducted. For several underground sites, a satisfactory, correlation was found between underground measurements and three-dimensional numerical simulations using a boundary element code in the linear elastic domain. However, to simulate bed separation, and roof block collapses more complex models were required, of which examples are presented.

Jan 1, 1992

By M. R. Peterson

The U.S. Bureau of Mines has investigated new methods for increasing the selectivity in flotation by creating and regulating reagent concentration gradients within flotation columns at steady-state operation. Gradients were generated and traced in a water-only system with the use of fluorescent dyes, and the effects of various operating parameters on these gradients were investigated. From this investigation, it was found that both gradual and steep gradients could be generated in the froth cleaning zone, and that these gradients could be changed through the manipulation of both physical and chemical operating parameters. The application of reagent-gradient control to mineral systems could improve both flotation grade and recovery in commercial flotation operations without the use of additional flotation circuitry.

Jan 1, 1992

By Tuncel M. Yegulalp

In this paper we revisit the well known "Ultimate Pit Limit Problem" and suggest an alternative approach for fast and efficient solution. We follow the approach originally proposed by Johnson and Barnes (1988), but utilize the "Excess Scaling Algorithm" in solving the equivalent maximum flow problem. This algorithm provides significant increases in speed and reduction in memory requirements over the well known Labeling Algorithm of Ford and Fulkerson (1956), enabling one to solve large problems with relatively small computers. We present results of a series: of benchmark tests using this approach against the well known Lerchs Grossman algorithm as well as a brief description of the new algorithm.

Jan 1, 1992

By P. R. Taylor

This investigation (Bowles, 1990) involves consideration of technology utilized by three separate fields of metallurgy and materials science: 1) The recovery of metals employing the use of solvent extraction, 2) The fabrication of materials using powder metallurgy, and 3) The use of composite materials in fabrication of engineering materials. The research considers each of the processes in order to realize the benefits of each. In light of the fact that materials have an intended use -it does seem plausible to simplify the process required between "mother earth" and final use. For instance, a primary copper producer that already employs a solvent extraction and electrowinning process could produce value added products directly. Part of the existing extractant flow could be diverted into a pressurized hydrogen stripping process in order to produce specialty composite powders. Innumerable methods have been employed for the recovery of metals; solvent extraction, the one considered in this study, was used due to the possibility of it providing a pure powdered metal. The use of solvent extraction in the recovery of metals has gained wide acceptance and its use proves beneficial in many applications (Ritchey and Ashbrook, 1984). Pressure hydrogen stripping of solvent extractants may provide the benefit of flowsheet simplification compared to conventional solvent extraction followed by electrowinning. It may also provide the benefit of direct production of high purity metal powder (Demopoulos and Distin, 1985).

Jan 1, 1992

By Charles L. Kimbell

In overview, the world's mineral industry in 1989 registered gains over its 1988 performance, but these gains were by no means as pronounced as had been those of 1988. The traditional statistical measures of mineral industry performance, namely production, trade, and consumption levels, reflected significant growth in most industry sectors from crude material extraction through the gamut of down- stream processing. Growth in market economy countries generally exceeded growth in the centrally planned economy countries as a result of a variety of causes that will be covered subsequently, but even among the centrally planned countries there were some upturns. In contrast to these measures of the soundness of the industry, the situation for nonfuel mineral and metal prices was less satisfactory than in 1988, and low crude oil prices continued as a problem for the all-important petroleum sector, despite some gains during the year. The oil price situation mitigated against price increases for competitive fuels. Although this was unfavorable for fuel producers, it remained advantageous to consumers, including nonfuel mineral producers, processors, and transporters. Thus it cannot be viewed as a negative factor for the whole of the global mineral industry. Global crude mineral output value was estimated at nearly $1,420 billion in current dollars, an increase of 9% over the 1988 level, and an increase in current dollar terms for the seventh consecutive year. Measured in terms of constant dollars, however, adjusting for inflation, the increase was only 4.7% compared with the 1988 level. Despite the prolonged growth trend, the 1989 crude mineral output value level was still 3.2% below the record high set in 1980, which was $1,467 billion in terms of 1989 dollars.

Jan 1, 1992

By Anderson J. M, Gillies A. D S, Jones N

There are a number of current theories in relation to methane migration and emission into workings following underground coal mining activity and some controversies do exist. Mining causes changes in the stress regimes in surrounding strata and results in fracturing. Permeability increases and methane flows into workings under a pressure gradient. The effects of stress on permeability depend on the physical properties of the coal and surrounding strata. Methane emission also depends on the original methane content and the proportion which will be liberated. There are several methods for determining in situ methane content and desorption characteristics of coal samples and several methane prediction methods but clearly more research is necessary to achieve an adequate predictive model.

Jan 1, 1992

By Jorma Miettunen, Reijo Kalapudas, Pertti Koivistoinen

A new method for measuring the mill filling was developed by Outokumpu’s Pyhäsalmi concentrator during 1989-90. The method utilizes the power draw oscillation which is caused by the mill lifters. Each lifter bar causes a peak in the power draw and thus a continuous oscillation results. In a fixed time scale, the oscillation peaks will shift as the lifter bare hit the mill charge sooner or later depending on the volumetric filling of the mill. Thus the measuring method is based on the phase shift of the power oscillation. So far the measurement is utilized for maximizing throughput of the primary mills at Pyhäsalmi and Enonkoski concentrators and at Harjavalta slag concentrator. The paper describes the new method and the results achieved.

Jan 1, 1992

By J. M. Dean

The MANpower SUPport Program (MANSUPP), a part of the Mine Management Support System (MMSS), allows an underground coal mine site user to determine manpower requirements for production support work by considering ongoing operations and current mine conditions. The objective of MANSUPP is to plan a detailed manpower structure for a mine by incorporating a production schedule, condition-modified work standards and management preferences to predict required manhours for various activities, for example, belt moves. The program is written in Quattro Pro version 3.0 (Lotus 1-2-3 compatible) utilizing the command language, macro and formula capabilities.

Jan 1, 1992

By Ichinose M, Tsuru T, Gotoh K

Since 1980, the Department of Mining Engineering at Kyushu University, in co-operation with the Ikeshima Colliery, Matsushima Coal Mining Co. Ltd., has been conducting a research project into longwall gateroad designs applicable to deep and poor strata conditions. During this period, the economic environment has drastically changed the situation of the domestic coal mining industry. Conventionally, the retreat longwall method, with re-use of gateroad, has been employed as it achieves higher recovery. However, from the view point of production efficiency, this method is not suitable because it requires intensive work in side packing and roadway maintenance. Therefore an interpanel-pillar system, or a two-entry gateroad system, was adopted to identify the factors responsible for excessive vertical closure in longwall gateroads. Field measurements and non-linear finite element analyses were undertaken to confirm the performance of this system. Study results indicate that the stability of the gateroad employing the rib pillar system is comparable to that of the conventional system of re-using Gateroads.

Jan 1, 1992