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By Robert S. Mayo

The haulage of muck from mines was first illustrated by Georg Agricola in De Re Metallica in the year 1556. In many of his ancient wood cuts he showed a crude car running on wooden rails. These wheels had no flanges. There were four pins sticking down from the car to guide it along the rails. Eventually they made the wheels of cast iron with flanges on them. In England, coal was hauled from the pit mouth to the nearest river or canal in "wains", or wagons, running on the common highways. These wains carried one chaldron of coal, weighing 2500 lbs and it took six horses to haul these wains over the atrocious roads of that day. Somebody, about 1760, invented a cast iron rail. These were cast iron troughs, 4 ft long laid on wooden sleepers. With these iron rails they found that one horse could do the work of six. But this U-shaped groove trapped all the dirt and grit. Somebody had the brilliant idea of attaching a flange to the inside of the wheel and from then on the rails were of timber protected against wear by a strap of iron. Rolled rails, of wrought iron, were first used in England in 1820. I am sure that many of you people have wondered why the British and American railroads standardized

Jan 1, 1974

It took me nearly nine months to make the move from Arizona to Berkeley, opening an office and planning our new home. While I was in Warren Dorothy had rented two rooms for my office In the new California Commercial Union Building at 315 Montgomery Street in San Francisco. She made such a good choice that this remained my address for more than 50 years Dorothy had also looked over many lots In Berkeley, and took an option on the one that pleased her the most. It was a beautiful lot, or rather three, as we took three lots to protect our view. The only possible drawback was that it was in a new district and there were only two houses within two blocks. No one could tell how the area would develop but we liked it so much that we bought the lots on the spot and signed a note to guarantee payment. Dorothy's good judgment was shown by the fact that after 50 years we are still glad to be living on the same property, at 168 Southampton Avenue. We arranged a meeting with the distinguished architect Bernard Maybeck-and employed him to design a house for us. Dorothy spent most of her time with Maybeck planning the house and an attached studio for her, and she later wrote an amusing essay on her dealings with Maybeck. They were so successful that even now we could not think of any changes we would have wanted. It took several months to design a house that suited Dorothy and would fit on our hilltop. I was glad to overcome some of Maybeck's scorn for "only an engineer" by showing how, by rotating the studio addition 45º, it would fit the lot without serious excavation. We finally signed a contract with Maybeck, borrowing so much money that it scared us. First Consulting After short jumps to the gold mines in the Secret Pass District near Kingman, Ariz., and to the Espiritu Santo prospect adjoining the rich

Jan 1, 1976

By Babcock. C. O.

This report presents equations derived from experimental testing to convert borehole pressure cell data from vertical and horizontal cells to the biaxial ground stress changes. While hydraulic pressure cells in boreholes have been in extensive use since 1957, methods of data reduction have been slow to develop. The methods of Sellers (1970) and Bauer et al. (1985), respectively, indicate a linear relationship between cell pressure change and the rock stress change. Lu presented a theory for creep behavior (Babcock et al., 1982). In the present work, in laboratory testing, the logarithm of the cell pressure was related to the stress change in seven elastic materials for a range of Young's moduli of 3.45 to 85.5 GPa (0.5 to 12.4 x 106 psi). The gage response depends upon the setting pressure of the gage, the gage pressure at any time, the rock properties, and the cross-sensitivity of the gage to transverse loading. The setting pressure of the cell should be proportional to the Young's modulus of the rock, the absolute stress can be determined by overcoring in strong rock, and the in situ Poisson's ratio can be estimated in some cases from the cell responses.

Jan 1, 1986

By J. B. Hiskey

INTRODUCTION The extraction of gold and silver from ores, concentrates, and various metallurgical products can be achieved by a number of hydrometallurgical techniques. The solvation properties of alkali cyanide solutions on gold and silver were recognized 200 years ago. A cyanidation process for leaching gold from its ore was patented in 1887 and 1889 by MacArthur and Forrest. The solvent action of thiosulfate on gold and silver was observed over 100 years ago. Recently, several patents have been issued for processes using ammonium thiosulfate as lixiviant for precious metals, Berezowsky, et. al (1978) and Kerley (1981). Tozawa and and coworkers also examined the dissolution of gold in ammoniacal thiosulfate solution. Thiourea leaching of gold and silver initially discussed by Plaksin and Kozhukhova in 1941 but has received only limited attention since that early work. Use of thiourea as an alternative to cyanide was the topic of several papers presented at the 1981 AIME annual meeting In Chicago, Illinois. Hiskey provided a review of the fundamental chemistry of the dissolution of gold and silver in acidic thiourea solutions. Pyper and Hendrix reported on the leaching of a finely disseminated gold ore using thiourea as a lixiviant. The review article(6) previously presented was fairly comprehensive covering Important contributions to the chemistry of thiourea and the processing of gold and silver with acidic thiourea solutions. A search of the technical literature was made to determine recent (since 1981) progress and developments in applying thiourea to the processing of gold and silver. This review reveals that Soviet and Eastern European scientists are continuing to make major contributions to our understanding of thiourea/precious metal systems.

Jan 1, 1984

By Bruce S. Brown, Jeremy P. Haile

The construction of tailings facilities and heap leach pads for gold mining operations generally requires the installation of one or more impermeable liners beneath the structures to satisfy environmental regulations and prevent the leakage of gold bearing solutions. Liners are usually constructed using clay soils or synthetic membranes, such as high density polyethelene. Low permeability soil liners can be constructed from natural clays, well graded soils with only a small clay content, or sandy soils blended with a small quantity of imported clay such as bentonite or kaolinite. The permeability of such materials, prgperly pped with good quality control, generally lies in the range of 10- to 10- cm/s, and can be designed to meet minimum prescriptive standards set by regulatory agencies. Important benefits resulting from the use of clay liners include the slow rate of penetration of a saturated wetting front, the decrease in permeability of the liner as it consolidates under the applied load of tailings or ore, and attenuation of potential contaminants in the process solutions. Synthetic liners can be attributed a finite permeability as a result of minute perforations and seaming deficiencies, and possess none of the above properties. Synthetic liners are also, by their nature, relatively thin and even a small head build-up above the liner will result in a large hydraulic gradient across it.

Jan 1, 1988

By J. Engesser

A research project was undertaken to determine if coal addition tofluxed-magnetite pre-fired pellets would reduce nitrogen oxide (NOx)emissions during pellet induration. Iron oxidation rate tests, coal oxidation rate tests and calcination rate tests were conducted in a laboratory furnace to determine the amount of coal necessary to provide adequate heat for limestone calcination without producing detrimental effects to magnetite oxidation. Pilot scale pot-grate tests were then performed with and without coal in the pre-fired pellets to verify pellet quality parameters and nitrogen oxide emissions. The off-gas during each pot-grate test was analyzed for NOx, CO2, CO, SOx, and O2. There was approximately a ten percent reduction in NOx emissions with coal addition during the normal pot-grate firing cycle. There was a 75% reduction in NOx emissions during firing cycles that used 25% to 75% excess air during firing rather than the normal 300% excess air.

Jan 1, 2003

By S. K. Kawatra, M. T. Rusesky, T. C. Eisele

An on-line monitoring system for apparent slurry viscosity has been developed at Michigan Technological University. It utilizes a vibrating sphere viscometer in conjunction with a special slurry presentation system to reduce particle settling and turbulence effects. It has proven to give accurate, reproducible results in an on-line hydrocyclone installation. Its performance shows that it can be an effective instrument on an industrial scale, particularly in grinding circuits. Development of the sensor and the importance of rheology in grinding are also discussed.

Jan 1, 1992

The next 13 years gave me an education that anyone, then or now, would well envy. W.T. Reid had founded Belmont School along the lines of Groton and, as at Groton, he sent many graduates to Harvard. He obtained excellent teachers and maintained as strict a discipline as the independent nature of the western students would stand. With a beautiful location in an unspoiled little valley in the foot- hills of the Coast Range there was every chance for walks and expeditions. The years at Belmont were good ones. My closest friends were Harold Jordan and Lewis Hackett. Lewis was son of the military director at the school. With half a dozen other very young inmates we early won the sobriquet of "The Dirty Dozen." Sliding down a steep muddy hill on barrel staves helped us earn the name. An inherited shyness exaggerated my sensitivity at being a "teacher's boy" and this prevented a close association with the wilder western boys who made up most of the schoolmates. Trapping wildcats and coyotes in the brush-covered hills and taking long walks gave me plenty to do. I had grown too fast and when I went to college was 6 ft 3 in. tall and weighed only 145 lb-hardly a respectable bean pole. I was only two months past 16 when I left for Harvard. The long summer vacations were happy ones. Most of them were spent in the high mountains, and even when I was ten years old I could keep up with anyone on long steep climbs. I learned to handle a rowboat during our stays at Lakeside, a rustic resort at the south- east corner of Lake Tahoe that could then be reached only by the steamer that made a dally trip around the Lake. Several of the teachers at Belmont remained good friends as long as we were on the same side of the continent. The finest was C.H. Rieber, who taught mathematics at Belmont for the first few years we

Jan 1, 1976

By Barry Cloutt

Western Mining Corporation Limited owns and operates the St Ives Gold Plant located near Kambalda, approximately 90 kilometres south of Kalgoorlie in Western Australia. Production commenced in March 1988 at a design capacity of approxi­mately two million tonnes per year. The plant was quickly expanded as a result of new ore discoveries in the district and has been processing ore since 1993 at the rate of three million tonnes per year. The plant has recovered over 50 tonnes of gold since the operation began, The plant was able to maintain acceptable recoveries throughout the plant expansion phases. Further gains in recovery were possible since there was still free gold in the tailings after approximately 24 hours of leaching. Testwork carried out on prospective orebodies showed that some contained considerable quantities of free visible gold, while others were seen to be semi­refractory using a conventional grind - leach circuit. Alternative treatment techniques were considered because a substantial amount of revenue was lost with the treatment of these ore bodies using conventional milling techniquies. The basis for all the investigations was to maximise the gold recovery from each orebody while minimising the effective cost per ounce of gold produced,

Jan 1, 1995

By W. V. Harper

The travel path of a freed radioactive particle in an aquifer must be estimated from a limited number of available samples. This paper discusses geostatistical methods that minimize the 'uncertainty' associated with the predicted hydrologic surfaces and the predicted travel path. However, any estimation method will produce a single smooth predicted path. This 'sensitivity' will he evaluated using a geostatistical simulation method. The techniques will be illustrated using published data from the Wolfcamp and Pennsylvanian aquifers in the northern Texas Panhandle.

Jan 1, 1990

By J. G. Groppo, B. K. Parekh

A series of performance studies were conducted using countercurrent column flotation to recover a marketable clean coal product from existing preparation plant fine waste streams. The test work was conducted at several preparation plant sites in Kentucky and Virginia using a 150-mm (6-in.) inside diameter column that was 5.8 m (19 ft) high. Both thickener feed and classifying cyclone overflow with a typical size distribution of 150 µm (100 mesh) X 0 were tested. The percent solids of the column flotation feed varied from 1.5% to 15% while the ash content ranged from about 30% to 60%. The concentrates produced contained 2% to 10% ash with Btu recoveries of nearly 90% using 0.12 to 1.25 kg/t (0.25 to 2.5 lbs per st) fuel oil and 0.12 kg/t (0.25 lbs per st) MIBC. These results were consistent with or better than results obtained in preliminary laboratory scale column flotation evaluation. Test results from seven different seams are discussed as well as scale-up relationships used to design a full-scale installation presently in operation.

Jan 1, 1991

By Photios G. Ioannou, Guillermo F. Salazar, Herbert H. Einstein, Yeong W. Kim

The MIT tunneling group has developed, over the past decade, a number of decision support tools for the geologist and engineer, planner and designer, owner and contractor involved in underground construction. These computer based tools can be used in the planning and exploration stage of a project, in predesign and design, in construction planning and during construction. Tasks as different as optimizing information collection during exploration and during construction, as selecting major design alternatives in predesign and modifying design during construction, as providing cost and time estimation and considering social and physical environmental constraints, can be handled. Output can be in the form desired by the user ranging from geologic profiles (cross sections) to management reports.

Jan 1, 1987

By Brij M. Moudgil, Shoulian Zhu, J. L. Pinault

A new technique, prompt neutron activation probe (PNAP), for analyzing phosphate rock slurry in-situ was evaluated both in the laboratory and at the plant. The technique yielded a high precision in the analysis of Ca, Si and H using 252Cf source. Low accuracy of the direct measurement of P using 241Am/Be in the laboratory tests was attributed to the interference of rare earth elements present in the samples, particularly Gadolinium. No significant effect of variables such as solids loading, particle size distribution, and flotation reagents was observed on the probe performance. The probe can detect the compositional changes of the feed, tailings and the concentrate streams in the plant.

Jan 1, 1993

By David K. Ingram

The objective of this U.S. Bureau of Mines investigation was to characterize overburden response due to longwall mining. Subsurface strata and surface deformations were monitored during the mining of two adjacent, 900 ft wide longwall panels in southeastern Ohio. The panels were separated by a five entry, four pillar system (about 350 ft wide). The overburden thickness in the study area ranged from 214 to 280 ft, and the extraction thickness averaged 70 in. To delineate the geology of the overburden, six coreholes were drilled along a profile line extending across the two longwall panels. Multi-point borehole extensometers (MPBX) with eight-anchors were installed in six boreholes to measure subsurface displacements. The MPBX units were continuously monitored using a data logger. During the mining of the first panel, displacement occurred in a radiating pattern beginning just above the extracted area in the center of the panel and extending upward and outward towards the surface and margins of the panel. Overburden deformation did not project over the gate road entries. During the mining of the second panel, the MPBX's showed almost simultaneous displacement, indicating that the overburden began to move as a whole unit. Again, overburden deformation was confined to the immediate panel area. At both panels, overburden movement began when the longwall face was approximately 55 ft beyond the line of MPBX boreholes. Moreover, all ground movement was complete when the longwall face was approximately 200 ft beyond the line of MPBX boreholes. This paper discusses the results of the study and identifies the characteristics of overburden deformation.

Jan 1, 1986

After the war that was nearing an end In early 1945, regular consulting work for Bralorne, the Bradleys, Pennsalt Chemical Co., and a directorship and occasional consulting for Homestake Mining Co. made it almost certain that in spite of my 61 years I would have enough work to feed my family. But this routine work would not provide enough income to lay up funds for the inevitable future when I could no longer do arduous work. And it would not give me the adventure that had first lured me into mining. Therefore I was greatly relieved as well as pleased when, in the 18 months from April 1945 to November 1946, I was asked to make three of the most adventurous as well as profitable examinations that ever came my way. Pati[n]o Mines, Bolivia The first of the exciting jobs was an examination of the Pati[n]o tin mines in Bolivia. After I had unsuccessfully tried to induce Anaconda to purchase these mines In 1915, the World War I crisis that had forced the half-Indian accountant to try to sell the mines had come to an end. The European market for tin improved dramatically, and "Don Simon" was able to borrow money for expenses while the concentrates were still In Bolivia. He took advantage of the favorable conditions by buying adjacent properties and increasing development work until his Bolivian tin mines were the greatest in the world. And his daughter had marled the French Count de Boisrouvain and was cutting a swath In high International society. Pati[n]o wanted to get rid of the drudgery of running a complicated mining Industry in a remote area In Bolivia when the fleshpots of Paris were much more seductive. An added incentive was the fact that his miners had become unruly and had even threatened his 11fe.

Jan 1, 1976

By D. Doepker

The dissolution of metals from various metal/ non-metal mine tailings has been studied through column leach tests at US Bureau of Mines laboratories. Metal mobilization in unsaturated columns was consistently greater than metal dissolution in water-saturated columns. Leachate pH was also frequently lower when a leachant was passed through columns but showed a mixed residence-time dependence. On the other hand, metal and sulfate ion concentrations in the leachate increased with dry-cycle residence time. Results suggest that acid formation through atmospheric oxidation of pyrite may compete with non-acid-forming oxidation of other metal sulfides. The two processes lead to decreased pH and increased metal mobilization, respectively. Leach tests using sodium lauryl sulfate indicated that microbial activity was not a factor in these studies.

Jan 1, 1991

By T. M. Ruff, W. G. McCoy, M. J. Beus, S. Iverson, W. Hasz

Technology to enhance safety during mine hoisting has been developed by researchers at the Spokane Research Laboratory of the National Institute for Occupational Safety and Health. Assessment of current hoisting technology suggests that monitoring conveyance position and load directly from the skip or cage top offers several significant safety advantages. Wireless data transmission schemes and a package consisting of sensors, batteries, and a charger mounted on the wire rope and skip have been developed. A state-of-the-art automated hoisting test facility was constructed to test the concept in a controlled laboratory setting. Field tests in a full-size shaft are underway.

Jan 1, 1999

By William E. Wallace, Larry Grayson, Thomas Simonyi, Joel C. Harrison

Application of an SEM-based methodology suggests a reason for past contradictory results on the relationship between quartz and coal workers' pneumoconiosis (CWP). Results indicate that coal seams with the same bulk analysis of quartz have different amounts of surface-available quartz. Our research shows that the amounts of pure and surface-available quartz in a respirable dust vary directly with the rank of a coal seam, except in the case where rock materials are mined. The estimated amount of surface- available quartz therefore provides a measure of the quartz-related fibrogenic potential of a respirable dust.

Jan 1, 1992

By V. Saltas

In the present work, dielectric spectroscopy experiments were conducted on bentonite samples collected from Milos Island, in order to study their electrokinetic behavior in correlation with water content and mild heat treatment. Low-frequency dielectric spectroscopy has proved to be a power tool in the study of the electrical behavior of clay-water systems, because polarization and relaxation processes typically affect response at frequencies below 100 kHz. Therefore, dielectric and conductivity measurements in the frequency range of 10mHz to 1MHz were carried out by means of a high-resolution broadband spectrometer on bentonite samples, at various levels of hydration. The evolution of dielectric response was also examined after annealing of the samples. Experimental data were computer fitted with the empirical Havrilliak?Negami dielectric relaxation function on which a conductivity term was superimposed. The evaluated parameters of the fitting function are shown to be strongly affected by the water content of the measured samples.

Jan 1, 2006

Up to the middle of 19 14, when I had reached what seemed like the advanced age of 30, I had enjoyed far more than my share of success and a lot of minor adventure. But the exciting experiences in distant lands that Soldiers of Fortune had made me long for had not yet materialized. And I had not accomplished the two goals that Mrs. Hughes' geography class at Belmont had set up for me. They were to see In its tropical home the enormous yellow bill of the toucan bird and to ride on a straw "bolsa" on Lake Titicaca. These aims were gratified In the next five years that were the epitome of "romance" in its German connotation of facts seen through the rosy glasses of imagination. Dr. Louis Ricketts was to a large extent responsible for my opportunity. I had been lucky enough to do a lot of work for and with the Doctor, as he was affectionately called by the mining men of the southwest. My association was in connection with his work with John Greenway on the complex metallurgical problems at Ajo. Soon after the Ajo investigation Ricketts had been made chief consultant for the Anaconda Copper Co. When Anaconda decided to undertake a cam- paign of exploration of the west coast of South America Dr. Ricketts thought of me and arranged with Greenway to give me a leave of absence from my Calumet and Arizona job. It took three days in New York in June 1914 to arrange the expedition. Ben Thayer, executive vice president of Anaconda, did most of the planning and I was to report to him. T.H. France, a 45-year-old mining engineer who had been driven out of Mexico by the Madera Revolution, was to accompany and help me. He spoke excellent Spanish and his years of Mexican experience had taught him how to get along with Latin Americans. He went ahead to Bolivia, our first target, to get an idea of the country and the problems. This was lucky as I hardly knew where Bolivia was.

Jan 1, 1976