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By Greg R. Wheeler

Few members of the general public have a clear understanding of mineral resources. Most people do not know how minerals are mined or why they must be extracted from many diverse locations. Many people acquire knowledge of mineral development from mass media sources with incomplete details or obvious anti-mining bias. The California Mineral Education Foundation was formed in 1991 to provide educational opportunities for the public and industry. There have been major changes in earth science teaching requirements for kindergarten through 12th grade (K-12) curricula since the passage of California Senate Bill 813 in 1983. Model graduation standards, curriculum standards and the state science framework mandate substantial coverage of geoscience topics. The California State Commission on Teacher Credentialing has completed changes in multiple subject and single subject science credentials which will require more geoscience preparation for all teachers. The need for pre-service and in-service education in geoscience is at an all time high. Teachers must have continuing education to maintain their credentials and many are now seeking information in geoscience. The California Mineral Education Foundation designed and conducted the California Mineral Education Conferences held in August 1991 and 1992. The conferences involved lectures and field trips on mining geology, environmental problems and political concerns. Master teachers were employed to share how they get across mineral resource concepts in the classroom. Ninety-six percent of the participants stated that they had changed to a more positive perception of mining after taking the three day course.

Jan 1, 1995

By Richard J. Frechette

Final reclamation of mine tailings impoundments typically involves addressing the broad issues of surface stabilization and water management. Surface stabilization includes immobilizing the tailings particles and providing long-term protection of the containment facility. Water management typically includes provisions for handling both the external water (rainfall and runoff) and the internal water (pore fluids). Wet tailings disposal facilities, and sites with limited access and steep topography, present challenges to implementing effective surface stabilization and water management plans. This paper presents a generalized discussion of the approach to tailings impoundment reclamation based on project experience.

Jan 1, 1995

By C. A. Young

The remediation of cyanide (CN-) and nitrate (NO)-) anions in mine and agricultural waters by various photolytic methods has been reviewed and investigated. Photolytic methods such as direct photolysis, homogenous photolysis, and heterogeneous photocatalysis are briefly described and compared. Results and discussions show that each method has certain advantages and disadvantages. For each method, Eh-pH diagrams prove useful for determining reaction mechanisms. Preliminary results obtained for cyanide oxidation and nitrate reduction show that homogeneous photolysis can be superior due to faster kinetics than the other methods. The photolytic methods were individually, not simultaneously, tested and compared. Differences in concentrations of products were obtained and attributed to differences in photoconversion efficiencies and other inherent characteristics of .the photolytic methods. Various reaction mechanisms are proposed in accordance with the literature as well as measurements obtained from solution analysis using ion selective electrodes and ion chromatography .

Jan 1, 1995

By E N. Isaev, L E. Levin

New data on the geology of the Late Jurassic to Holocene sediments cover of the World and associated mineral resources (oil, gas, ferromanganese nodules, ores of massive sulphides and other metals) have been compilled in the Atlas at scale 1:25,000,000 and 1:10,000,000. The work was performed by scientists from four Institutes of Russia (VNIIzarubezhgeologia, VNIIoceangeologia, Vernadsky Institute of Geochemistry and Analytical Chemistry of theRussian Academy of Sciences and Geological Institute of the Russian Academy of Sciences). The Atlas shows variation of thickness and formational composition of the large complexes (Upper Jurassic-Early Cretaceous, Upper Cretaceous Eocene, Oligocene-Neogene, Pliocene-Pleistocene), distribution of oil/gas and ore deposits in each complex, data of deepsea drilling (leg 1-130),  thermo-pressure condition in the sedimentary basins within Circum-Pacific Rim.

Jan 1, 1995

By Meyer C. F

The increasing use of continuous miners in the extraction of high coal seams has amplified the need for enhanced ventilation systems in the headings. Owing to larger face dimensions and higher production rates, more ventilating air is required to effectively dilute liberated methane to acceptable concentrations. However, the increased air quantities raise and entrain greater amounts of dust, to which the operator is subjected. Various methods (eg sprayfans, on-board scrubbers and jet fans) are used in various configurations and combinations to ventilate the headings. These arrangements generally result in a complex air flow pattern, which complicates achieving an optimum balance between diluting methane and minimising dust capture. In order to cost effectively investigate and propose solutions to this problem for the South African coal mining industry, the Division of Mining Technology has embarked on an extensive work program to evaluate various ventilation methods presently in use. Four currently generic ventilation patterns in various heading scenarios have been simulated using the Computational Fluid Dynamics (CFD) computer program. Evaluating these outputs against a predetermined set of criteria allows the best system for a particular situation to be chosen. The program also facilitates fine-tuning of an adopted system without incurring the cost and inconvenience of doing such tests in situ. This process not only provides solutions at significantly reduced costs, but also yields deeper insights into the factors affecting heading ventilation than hitherto possible.

Jan 1, 1995

By C. Patrick

Annually, the U.S. coal industry generates and must dispose of over 200 million tons of coal refuse, expanding a major environmental problem. The purpose of this research was to investigate the feasibility of utilizing coal refuse as an aggregate in concrete. This paper reports on findings of the initial phases of a project to determine the viability of replacing traditional concrete blocks, used for under-ground ventilation stoppings, with refuse blocks. Refuse was collected from three active preparation plants in Eastern Kentucky and used as the primary aggregate for concrete cylinders. The refuse fell within ranges normally observed for size consist, moisture, and ash. Stress-strain analyses yielded compressive strengths of the refuse cylinders from 59% to 77% of the control group strengths. Low variability within groups while significant differences between groups were found. On-going determination of effects of weathering on the refuse cylinders is being conducted and will be completed in early 1995. The research results are favorable for the future direction of the overall project objectives.

Jan 1, 1995

By D. R. Boyle

"Abstract - The Murray Brook precious metal (Au, Ag) gossan deposit is one of nine supergene mineral deposits that have developed over polymetallic massive sulfide deposits in the Bathurst Camp of New Brunswick. Reserves consist of 1.9 Mt of gossan containing 1.53 g/t Au and 65.9 g/t Ag. The supergene zone at Murray Brook consists of six distinct units: a) altered massive sulfide, b) pyrite-quartz sand, c) massive sulfide gossan, d) disseminated sulfide gossan, e) ferruginized wallrock, and f) leached bedrock. The massive sulfide gossan constitutes the main body of economic mineralization and consists of goethite, primary quartz, secondary amorphous silica, K-Fe-Pb-As- Sb-Ag hydrated sulfate and oxide minerals (beudantite, plumbojarosite, jarosite, bindheimite, scorodite), trace cinnabar, and cassiterite of primary origin. The order of stability of sulfide minerals during oxidation was pyrite > arsenopyrite > galena > Bi-Sb sulfosalts > chalcopyrite > tetrahedrite group > sphalerite.Two mass balance techniques (isovolumetric and conservative element) indicate elemental depletion in gossan relative to primary ore in the order: S>Cd=Zn>Cu=Mn>Na=Ca>Fe=Al=V> Mg= K=Se=Hg>Pb>Ti>Ag>Mo=P>Ba; and enrichment in the order Au>As>Sb>Si>Bi. Tin, as cassiterite, is conservative.Mineralogic and paleomagnetic data suggest that the gossan deposit formed under a warm temperate climate throughout the Pliocene. The rate of oxidation and the compositional nature of the ore was significantly influenced by: a) the position of the primary sulfide zone in a downward moving hydrological system, b) primary sulfide composition and zonation that promoted the development of a strong electrochemical oxidation system, and c) pronounced intercalation of carbonate and sphalerite mineralization in sulfide zones, which promoted rapid development of secondary porosity, permeability and downward flow of oxygenated groundwater.During progressive oxidation and physico-chemical erosion of the gossan zone, Au was trans- ported downward in groundwaters, probably as a Auo colloid complex, to be concentrated in the lower horizons of the gossan profile. The precipitation of Au was greatly increased in the pyrite/arsenopyrite zones. Gold concentration was multi-cyclic with continual dissolution and nucleation of the metal until final concentration in the void structures of the gossan. Leaching experiments and microprobe analyses indicate that Au is present in the gossan as submicron composite sols of Au-Ag-silica."

Jan 1, 1995

By Shuguang L, Jing S

Computer controlled truck dispatching systems is a newly-developed technical system in surface mines with shovel-truck technology. The real time dispatching criteria, as the core of optimal truck dispatching software, are analysed and a new criterion, complex dispatching criterion, is put forward. Dispatching criteria previously proposed include: 1. `Earliest Loading' (EL) - to assign a truck to the shovel at which the truck can be loaded earliest. 2. `Max Truck' (MT) - to assign a truck to the shovel at which the truck will have the shortest waiting time. 3. `Max Shovel' (MS) - to assign a truck to the shovel which has been waiting for the longest time. 4. `Minimum Saturation Degree' (MSD) - to assign a truck to the shovel at the branch where the truck flow saturation degree is minimum. 5. `Minimum Saturation Degree with Truck Cycle time consideration' (MSDTC) - as the MSD principle, with the truck travel cycle also considered. 6. `Fixed Dispatching' (FIX) - to assign trucks to fixed shovels. A system simulation model has been set up for truck dispatching system analysis. A few surface coal mines have been selected for case studies. Equipment waiting times and shift production of the system are obtained as the main outputs of the model. Simulation results show that each dispatching criterion has its own applicable range, no one can absolutely dominate the others. For example, when under-trucked, EL and MT criterion can obtain higher production than the MS criterion; when over-trucked, it is vice versa; while for MSD criteria, better results can be obtained no matter how the truck numbers fluctuate. From the view point of shovel output balance, large fluctuations occur for EL and MT criteria, while a good balance can be obtained for other criteria. In the light of dynamic change of mining system conditions, a single dispatching criterion is not necessarily reasonable. A complex dispatching criterion has been put forward to seek the complex optimum effect. Taking the advantage of each dispatching criteria, the dispatching result of a complex dispatching criterion dominates over individual dispatching criterion and a comprehensive optimum effect can be reached.

Jan 1, 1995

A geologic, petrographic and geochemical study has been performed on the pyroclastic flow deposits in the coastal area of East Zhejiang Province, Southeast China. This study leads to classification of the pyroclastic flow deposits into three associations: the extrusive type, the surge type and the ash flow type welded tuff associations. Through detailed investigation and comparison of the characteristics of these lithologic associations, with emphasis on the welded tuffs, a comprehensive model has been proposed to demonstrate the petrogenesis of the pyroclastic flow deposits.

Jan 1, 1995

In eastern China, most of the copper skarn deposits occur in folded troughs which are controlled by the EW-trending faulted fold systems (the Pal-Asian geotectonic domain), and the NNE-trending rift or fault zones (the Marginal-Pacific geotectonic domain), particularly the later. From the north to the south, there are four troughs hosting the main copper skarn deposits in eastern China: the Yanliao Trough, the Yangzi River Trough, The Qiantang-Yuanshui Trough and the Zichen Trough. There are more than 30 copper skarn deposits in eastern China, and ore reserves of each deposit are between 30 to 100 Mt with average grades over 1% Cu.    Most of the large copper skarn deposit-related intrusions are Mesozoic in age (170 to 100 Ma) and were emplaced during the Yanshanian Movement. Outwards from the intrusion bodies, both the skarn alteration and mineralisation show certain patterns of zonation. Mineral assemblages indicate a relatively high oxidisation state during metasomatic alteration and mineralisation. Sulphur isotopic work indicates that most d34S values of the sulphides are between ~4 to 3ë suggesting a common magmatic sulphur source. Fluid inclusion and oxygen isotopic studies suggest that early-stage fluid shows magma-related fluid characteristics although meteoric water was involved during late-stage alteration.

Jan 1, 1995

Our ultimate resources come from the Sun and the Earth System. At this time we face a world crisis in energy, water and soil resources. Global pollution problems are increasing in almost all nations. There is an urgent need to use our vast knowledge with a new wisdom and this requires new integrated teams of experts to provide the best alternatives for the needed new development problems. These teams must include economists, engineers and a broad spectrum of scientists. Today it is possible to produce clean energy, stop soil erosion, clean water and reduce and use wastes of many types.   There is a great need to improve science, natural science, education at all levels. All people must know how our planet works and that fluctuations, some inevitable, some controllable, are inevitable and that we must prepare for them. And it is clear that protecting the environment, eliminating pollution, preserving bio diversity is good economics. Ecology Economy cannot be separated.  

Jan 1, 1995

By Andrea B. Baldwin

In recent years, federal and state regulatory agencies have tightened air emission standards. Two of the acid gases, hydrochloric acid (HCI) and sulfur dioxide (SO2), are under heavy scrutiny for reduction. . Most traditional scrubbing systems, i.e. wet scrubbers and spray dryers, meet the standards but they typically are high in capital cost, have significant space requirements for equipment, and are difficult to maintain. Dry sodium injection (DSI) is a alternative technology that has been shown to be effective in HCl and SO2 removal while being the inverse to the problems listed with traditional systems. This paper covers the mechanics of dry injection scrubbing using the most effective sorbents, sodium bicarbonate and mechanically-refined trona (natural sodium sesquicarbonate). It presents DSI performance data for Chambers Medical located in Hampton, SC. This facility incinerates local medical and municipal solid waste. Chambers Medical has used mechanically-fined trona for HCl and SO2 removal since late 1991.

Jan 1, 1995

By S. K. V. Avasarala

This paper presents a case history of design, prediction, probe and production pile driving monitoring, loading tests and installation of over 3,300 prestressed concrete piles for a building complex consisting of 12, 5- and 6-story over parking buildings. The project was recently completed in three-phases over a span of 4 years. The subsoil conditions were explored by performing 25, Standard Penetration Test (SPT) borings throughout the site. Various types of driven pile foundations were considered and following an evaluation of high structural loads and site-specific constraints such as variable depth of bearing layer of Florida limestone and quality of clay and limestone layers, a prestressed concrete pile support system was selected as the most economical and effective foundation approach. The building foundations were designed for a pile capacity of 353 kN (40 tons) in compression, 45 kN (5 tons) in lateral capacity for a deflection of 0.64 cm (0.25 in.), and 133 kN (15 tons) in uplift capacity. The axial and lateral allowable pile capacity and lengths were predicted using SPT91 and LPILE computer programs, which are generally used in Florida. The validation of these capacities was derived from 144 probe piles and performance of 12 pile loading tests on selected probe piles. Prior to installation of probe or production piles, a termination criterion was established using 1-dimensional wave equation analyses in addition to the design pile embedment requirement. The predicted pile capacities compared very well with the capacities from the loading tests on probe piles. This information was effectively utilized as part of the overall quality control program to install a total of 4,186 prestressed concrete piles (including 144 probe piles) in different building areas across the project site to depths ranging from 8 to 21 m (25 to 90 ft) below existing ground elevation as part of foundation support system. This engineered, monitored, and tested foundation solution provided an effective and satisfactory basis for completion and approval of the foundation work for this 12, 5- and 6-story over parking building complex. A recent reconnaissance has indicated that all the building foundations are performing satisfactorily.

Jan 1, 1995

By Ritter K-C, Sturgul J. R, Filess T

The proposed Lihir open pit gold mine is located on Lihir Island in New Ireland Province, Papua New Guinea. The mine will be located within a volcanic caldera, part of which forms the adjacent Luise Harbour. Kennecott Corporation started engineering design work in 1988 and ended in 1993 when a Feasibility Report was submitted to the Papua New Guinea government by RTZ/Kennecott. The project will be managed by the Lihir Management Company. The mining operation will produce approximately 350 Mt of waste and 62 Mt of low-grade ore over the life of open pit mining. Landforms and traditional land use by Lihirians preclude storing mine waste and some of the low-grade ore on land close to the mine site. The mine waste will be composed of hard rock and soft soild like material which cannot be safely used to construct large land waste repositories by truck dumping. Submarine disposal by bottom discharging barges is the only safe disposal method. The barges will also be required to construct a waste platform along the shore for stockpiling low-grade ore. A simulation model of the waste handling system was written in GPSS/H¦ to assist engineers in selecting the optimum size and quantity of barges and loading docks by analysing the interaction between excavators, trucks and barges. The simulation model was written in enough details to model the various functions that will be encountered during mining. Input parameters allowed for variations in the size and number of trucks, shovels, barges and loading docks. Variations in loading, hauling, and dumping times were from user specified distributions. In order to visualise the interaction between the components of the waste mining operation, the simulation was animated using Proof AnimationT""'. It is believed that this is the first application of an animated simulation study for a mine still in the planning stages.

Jan 1, 1995

By M. N. James

The Fracture Research Group has been operating at the University of the Witwatersrand for some ten years and, in that period, has achieved a significant profile, both nationally and internationally, through its research publications, industrially-based technical reports, continuing short courses in engineering education, and co1Jferences. This paper outlines the activities of the Group over the past few years, emphasizing the research thrusts and the results that have been obtained, as well as highlighting areas of current and future research interest The capabilities of the Group in terms of equipment and expertise are also discussed briefly.

Jan 1, 1995

By Carl C. Nesbitt

A process has been developed to recover and recycle metals from wastes of brass foundries which contain copper, zinc and lead in various quantities. Tests were conducted to evaluate several leachants, including sulfuric acid, ammonia, hydrochloric acid, cyanide and acetic acid, and to determine the optimum leaching conditions, such as air flow rate, initial copper ion concentration, temperature, and agitation strength. Sulfuric acid containing copper sulfate with dissolved oxygen is the most successful leachant. More than 99% of the copper and zinc originally present in the waste was dissolved, while only 0.5% of the lead entered the solution after 14 hours of leaching. The leaching mechanisms of copper, zinc, and lead are proposed. The copper and zinc can be recovered from the solution by electrolytic processing. The unleached residue may be converted to a lead carbonate which can be converted to litharge at 400-450°C and to massicot at temperature above 500°C by calcination.

Jan 1, 1995

By J. M. Mutmansky, B. Kolonja

A PC-based simulation model using the software packages SIMAN and CINEMA was developed to simulate and animate truck-shovel operations. The model is capable of simulating one mathematical dispatching strategy using linear and dynamic programming and six heuristic dispatching strategies. Data were collected from an actual operating mine through time studies and analysis of historical records. Statistical analyses were performed, and appropriate theoretical distributions were fitted for various time events in the truck-shovel cycle. The model was then applied to study overall impact of these dispatching strategies on constrained and unconstrained mine productivity. The simulation/animation model developed in this study seems to be an efficient planning tool for choosing optimal fleets and finding an optimal dispatching strategy to produce an equilibrium between the quality and quantity of production.

Jan 1, 1995

By Olofsson O, Durance M-V, Villeneuve J

Modelling of the Sala Agitated Mill (SAM) using a simplified solution to the population balance approach has been carried out. The rate of breakage is modified by the mill power, providing predictions of the resulting product size distribution for different grinding conditions and mill sizes. The power of the mill is estimated by a physically derived function, using an assumption that the mill power consumption mainly arises from the ball to ball friction within the mill. The grinding efficiency, depending on the media ball size and pulp density is approximated in the model. Experimental work on grinding a complex sulphide ore using a pilot scale SAM 7.5 has been carried out. Good agreement has been found between the data from the test campaign and the simulated values. The model has also been validated with experimental data from a pilot grinding of calcium carbonate and from an industrial mill. The model is included in the USIM PAC simulation software.

Jan 1, 1995

By M. S. Klima

Tests were conducted to investigate the potential for recovering anthracite from preparation plant tailings. Samples were collected from tailings streams or slurry ponds of several anthracite cleaning plants. A washability analysis was conducted on each sample. The use of gravity-and surface-based cleaning processes for treating the 28x200 mesh tailings material was examined. Simulations were performed for various cyclone staging arrangements using published partition data for both water-only and dense-medium cyclones. Froth flotation testing was done on both precleaned anthracite and tailings material. Grade-yield curves were determined for various conditions.

Jan 1, 1995

By James R. Coldwell

Mining and processing cost analyses were conducted by the U.S. Bureau of Mines on stratiform zinc-lead-silver, coal, and stratiform barite deposit types that are found in the Colville Mining District. Reserves and gross revenues which would allow these deposits to be minable were modeled. A 15% Discounted cash-flow rate-of-return economic threshold was selected as the minimum acceptable return on investment for the three deposit types. The economic modeling indicated combinations of grades and tonnages for stratiform sulfide deposits that could be economically viable for orebodies ranging in size from 25 to 130 million metric tons. The gross revenues for a surface mine range from $200/mt for a 5,000 mtpd operation using the proposed South corridor to $140/mt for a 17,000 mtpd mine using the proposed North corridor. The economic modeling indicated underground coal mining was subeconomic for deposits ranging in size from 42 to 250 million metric tons. The required gross revenues ranged from $300/mt for a 2,200 mtpd mine to $21 D/mt for a 13,000 mtpd mine. The economic modeling indicated supplying projected in-state barite demand was subeconomic for the three seasonal surface mines modeled. The required gross revenues ranged from $600/mt for a 90,000 mtpy mine to $840/mt for a 6,000 mtpy mine.

Jan 1, 1995