Search Documents

By Lendall P. Warriner, Blandford C. Burgess

Jasper County lies just north of the geographical center of Georgia, bounded on the west and north by the Ocmulgee River. The county seat, Monticello, is approximately 65 miles east-southeast of Atlanta and 40 miles north of Macon. It is served by the Macon-Athens branch of the Central of Georgia Railway Co. and by five paved highways converging from adjoining county seats. Farming and lumbering are the principal local occupations. About half the county is covered with pine and mixed hardwoods; a large part of the forested land is owned by the Soil Conservation Service of the Department of Agriculture in its Piedmont Land Utilization Project. The topography is one of gently rolling field and forest with occasional hills rising 100 ft or: more above the creek beds. Though annual rainfall is in the neighborhood of 60 in., most of it falls in torrential downpours of short duration which tend rapidly to erode the red soil and convert the country roads to greasy tracks of red mud.

Jan 1, 1949

By Xinming Chen, Huazhe Jiao, Qi Zhang, Yunfei Wang, Liuhua Yang

The effect of initial damage generated by weakly cemented interlayer surfaces on the physico-mechanical properties of layered cemented tailings backfill (LCTB) is considered for the interlayer inclination structure generated by multiple layered backfills in large-scale mining voids. Utilizing the theory of damage mechanics, the damage evolution and constitutive model of LCTB with interlayer inclination is constructed by considering the coupling of interlayer inclination effect and loading. Based on Mitchell’s mechanical model, we analyze the damage mechanism of the inclined cementation surface of LCTB, and derive the expression for the strength of LCTB considering interlayer inclination. The mechanical properties test of LCTB with different inclinations was carried out, and the results showed that the damage model of LCTB established was highly consistent with the experimental curves, which verified the correctness of the model. The initial inclination damage leads to the decrease of adhesive cohesion of cemented surface, and with the increase of inclination, the separation of layered surface, aggravation of misalignment, layered cemented surface is more prone to shear damage, and the mechanical properties of cemented tailings backfill in the lower part of layered surface are not effectively played, which reduces the overall performance of the material.

Nov 23, 2023

By Hermes Vilchéz

El presente texto describe los beneficios de la apertura de los circuitos de flotación como alternativa de mejora en la performance metalúrgica de las concentradoras. El trabajo se efectuó en la empresa minera Los Quenuales, Unidad Iscaycruz (Lima), modificándose los circuitos cerrados a los abiertos y encontrándose los siguientes beneficios: el incremento del tonelaje de tratamiento sin aumentar equipos en los circuitos de flotación, la mejora en la recuperación y el grado de concentrados.

Sep 9, 2007

By M. van Schoor

The bulk of the world?s platinum production originates from the Merensky and UG2 reefs within the Bushveld Complex, South Africa. Both the Merensky and UG2 reefs are disrupted by faults, dykes, potholes and iron-rich ultramafic pegmatite bodies (IRUPs)?features that impact negatively on production, planning and safety. It is therefore advantageous to know of their presence and geometry ahead of mining. To date, no geophysical technique has been successfully applied to the routine mapping of mine-scale potholes and IRUPs. These disruptive features may vary from a few metres to several tens of metres in diameter. In this paper the applicability of in-mine electrical resistance tomography (ERT) to map potholes and other disruptions to the continuity of the Merensky and UG2 reefs ahead of mining is demonstrated using two case studies.

Jan 1, 2005

By Ray Hutton, Darrell Liebno, Taro Nonaka

Background Population growth and increasingly stringent regulatory controls on water quality across North America have resulted in municipal governments investing heavily in infrastructure to control what are known as Combined Sewer Overflows (CSOs).These are events which occur when combined sewers exceed their conveyance capacity during periods of heavy rainfall or snowmelt. The city of Atlanta, Georgia is one such municipality; with a population of over450,000 within city limits and a sewer system servicing 1.2 million including adjacent jurisdictions, the City of Atlanta has a Combined Sewer System (CSS) encompassing approximately 15% of its total 3,540 km (2,200 miles) of sewers. Atlanta’s CSO discharges to local watercourses began to draw fire from environmental groups in the1980s. As a result, in the early 1990s, the City constructed a series of CSO control facilities which provided screening and chlorination at seven CSO discharge points across the CSS watershed. Unfortunately, these facilities were not capable of handling all of the overflows generated due to heavy storm events; frequently, untreated water was bypassed around the treatment facilities. The federal Environmental Protection Agency (EPA) deemed that water quality standards were being violated by these discharges, and a suit was brought against the City to force a higher standard of compliance. As a result, the City entered into a federal Consent Decree which would bring CSOs into compliance with federal standards by 2007. A critical component of this plan was the design and construction of the West Area CSO Tunnels and Pumping Station. In February 2003 the City’s Department of Watershed Management retained the services of Jordan Jones & Goulding/Hatch Mott MacDonald/Delon Hampton Associates (JDH Joint Venture) to design and provide construction management ser-vices for the project, which was designed to capture combined sewage from three of the City’s existing CSO facilities on the northern end of the CSS watershed. The design consisted of two connected tunnels which would convey the wastewater originating from the North Avenue, Clear Creek, and Tanyard Creek CSO facilities to a submersible wet well pumping station located at the R.M. Clayton Water Reclamation Center (WRC). Since the majority of the effluent stream consisted of storm water, the City elected to design and construct a separate treatment plant. This plant was designed under a separate contract, and is currently under construction.

Jan 1, 2007

By Doris M. Hyde

There were no significant changes in the mineral industries of the smaller Caribbean Islands during 1980. Imported petroleum requirements continued to erode economic gains that may have occurred in other sectors. Some relief may be forthcoming as more qualified Caribbean countries take advantage of Trinidad and Tobago's petroleum product financing program (see Trinidad and Tobago). There were no crude oil discoveries in these areas during 1980, although some geophysical testing around the British Virgin Islands and Antigua war underway. In March 1980, the Government of Antigua sold a 75% interest in the 16,000-barrel- per-day West Indies Oil Co. refinery to the Swiss Intermaritime Bank and Intermaritime Management Services for $6 million. The new refinery company is called the National Petroleum Co. Shutdown since 1976, it was originally planned for the refinery to reopen in 1980, but refurbishing has proved to be more extensive than anticipated. The reopening is now expected in 1981.

Jan 1, 1982

By E. Lutz, M. Momayez, K. W. Brown Requist

As real-time air quality monitoring becomes more prevalent in US underground mines, it is important to provide the highest data reliability with the fewest possible sensors. Real-time sensors remain costly, and these costs are not exclusively financial; the time required to install, calibrate, and maintain real-time sensors poses a large barrier to widespread implementation. Current atmospheric monitoring systems typically rely on displaying point-specific values. This requires operators to infer real-time airborne contamination distributions. Monitoring and control software utilizing mine ventilation network (MVN) solvers has been implemented in limited cases because of their ability to simulate ventilation systems quickly, but these solvers use a one-dimensional representation of the mine, limiting spatial resolution of estimated distributions. Computational fluid dynamics (CFD) has likewise been considered as a means to improve spatial resolution, but processing times prevent its use as a basis for monitoring and control. For the real-time monitoring of airborne contamination distributions, we propose a spatial interpolation method that can estimate the distribution of airborne contaminants in near-real time. This method provides a middle ground between fast processing times and increased spatial resolution. With the use of a pathfinding algorithm and optimization through absolute percentage error minimization, this method outperforms spatial interpolation with a Euclidean distance. By providing contamination distribution information to operators, this method and its derivatives stand to outperform current atmospheric monitoring systems.

Apr 16, 2024

By Jarrod Bonsmann

"This paper presents the results of small scale testing to examine the effect of various importantparameters on the response of a vehicle due to the detonation of an explosive charge buried inthe soil below the vehicle. In particular, we were interested in examining what effect change instandoff distance, change in mass, and change in surface area would have on the loading applied.We examined the impulse delivered to the target in all cases and for the change in mass andchange in stand-off distance we examined impulse, kinetic energy, and acceleration."

Jan 1, 2012

By Daniel Ko, Ian Bell, Shahram Tafazoli, Bahram Sameti, Aylin Azmin

Image-based remote sensing of rock fragmentation in mining and quarry applications essentially treats each rock in the image as a data object in order to determine the rock size distribution. An obvious challenge after rock delineation in a 2D image is the scale of the delineated objects. Conventionally, either objects of known size are placed in the scene or parallel laser pointer are used, both making some assumptions, to calculate scaling factors. These assumptions are applied to the whole scene rather than sensing individual rock attributes.

Jan 1, 2015

By Gary A. Halvorson

Plots were established on regraded abandoned mine spoil to determine if nearby good quality spoil could be used in place of topsoil for the reclamation of these sites. Gypsum, calcium chloride, and power plant ash were also tested to determine the effectiveness of these materials in reclaiming these sites. Two sites were selected on which very little vegetation was growing on highly sodic spoil material. Gypsum, calcium chloride, and ash were added to the spoil at a rate designed to reduce the (sodium adsorption ratio) SAR in the surface 15 cm to 10 or less. The good quality spoil (replacement soil) was then laid on the swface at rates of 0, 5 or 15 cm of material. The plots were seeded to a mixture of smooth bromegrass (Bromus enennis Leyss.), crested wheatgrass (Agropyron desertorum (Fisch. Ex Link) Schult.) and alfalfa (Medicago sativa L.). The addition of 5 or 15 cm of replacement spoil significantly improved vegetative growth on these sites. Chemical treatments had no effect on vegetative growth. Weathered ash showed no adverse effects on plant growth or soil properties.

Jan 1, 1991

By Walter R. Storms

The Iron Mountain tungsten deposits first were visited by a field party of the Federal Geological Survey in May 1942 while beryllium deposits in that district' were being examined . Later they were examined by F. A. Rutledge , an engineer of the Bureau of Mines , and an exploration project was recommended , work upon which began in March 1943 and was terminated in April 1943 after intensive trenching and sampling had been completed .

Mar 1, 1947

The extra information brought by further drilling may seem necessary to achieve control over block grades if elementary estimation techniques are used. However a geostatistical study of an Australian deposit shows that better estimation techniques at the end of the first drilling campaign are sufficient to achieve required control.Subsequent drilling would be essentially wasteful.

Jan 1, 1975

By James S. Browning

Recovery of fine mica from a sample of impounded tailing from the Dixie Mines, Inc., crushing and screening operations, Heflin, Ala., was investigated to determine if plant losses of mica could be reduced while econmically producing a commercially acceptable mica concentrate. Conventional wet-tabling and agglomerate-tabling methods yielded concentrates assaying about 95 percent mica from the tailing that contained 17 percent mica. Products containing about 98 percent mica and accounting for mica recoveries of 86 percent were obtained by flotation, using as reagents sulfuric acid, kerosene, and coco amine acetate (a mixture consisting chiefly of dodecyl and tetradecyl amine acetates). The results of the batch flotation tests were verified by tests in a small continuous flotation pilot plant.

Jan 1, 1963

By Thomas P. Meloy

A brittle solid broken by crushing or impact, results in a mass size distribution curve having a straight line segment when plotted on log-log paper. Depending on the mineral, the slope of this straight line segment ranges from a maximum of one for materials like glass and quartz to values of one half or less. Theoretical derivations of the size distribution, such as the Gaudin-Meloy model, yield a slope of one and only one. When the Gaudin-Meloy model is modified to assume that not all cracks terminate on a preexisting surface, the new model predicts that size distribution slopes, depending on the type of brittle solid, will be less than one. There is a measurable physical parameter that will predict the slope. In addition the model predicts that particles from such a size distributions will have negative corners and peaks - indentations. Moreover the model predicts that particle shape will systematically change with decreasing particle size. Finally, this new physical model of comminution may be experimentally tested.

Jan 1, 1995

By D. Hopkins, D. Türler, R. D. Giauque, W. B. Davis, M. Karaca

In a highly collaborative research and development project with mining and university partners, sensors and data-analysis tools are being developed for rock-mass characterization and real-time measurement of mineral content. Determining mineralogy prior to mucking in an open-pit mine is important for routing the material to the appropriate processing stream. A possible alternative to lab assay of dust and cuttings obtained from drill holes is continuous on-line sampling and real-time x-ray fluorescence (XRF) spectroscopy. Results presented demonstrate that statistical analyses combined with XRF data can be employed to identify minerals and, possibly, different rock types. The objective is to create a detailed three-dimensional mineralogical map in real time that would improve downstream process efficiency.

Jan 1, 2002

The Junction Reefs gold bearing deposit is situated on the Lyndhurst Mining Field in mid-west New South Wales. It is located within a triangle of three country towns namely, Blayney, Cowra and Canowindra, all three townships are approximately 25 km from the current operational mining leases. The district is well developed, having been settled for more than a cen- tury. However, being close to the Cities of Orange and Bathurst it is real- lised, instantly, that mining leases have been pegged, in this area, almost boundary to boundary. The lease patterns are, with few exceptions, those which had been estab- lished more than seventy-five years ago. These types of lease patterns may not assist the proper exploitation of a large district where there have been many discoveries of gold, copper and other metals.

Jan 1, 1988

FREQUENTLY the Survey Department is caIled upon to estimate the quantity of material in various dumps, dams piles, etc... and in the carrying out of this work various methods may be employed.The method used will vary according to the particular case in hand, and factors such as accessibility of the top of the dump, steepness of its sides, height, and the condition of the material to be estimated. A certain amount of "give and take" must be adopted in the treatment of small local cavities and mounds.In all cases it is desirable that the surveys made should be tied on to the lease surveys for the purpose of location, and that all levels should be reduced to the mine datum. It is also desirable to obtain levels of the original surface before deposition of the material to be estimated. If these have not been obtained beforehand, levels and transfers round the top will be the next best. If space is availabIe, flat surface is chosen as a site for the dump, etc. This is of the utmost importance in those cases where the material will have to be...

Jan 1, 1925

By Felix G. Berra, David H. Orr

The first large scale application of radio remote control equipment to standard gage railroad trains has been achieved at the Morenci mine of Phelps Dodge Corp. at Morenci, Ariz. Twenty or more ore and waste haulage trains are remote control operated at any one time, each with a one-man crew. Reduction of train crews from two men to one man has materially lowered the total cost of train operation. Elimination of brakemen has also resulted in an improvement in train efficiency brought about by a shortening of train haulage cycle times.

Jan 4, 1965

By A. L. Engel

This report is a compilation of results of preliminary tests on scheelite (tungsten) ores and tailings. These investigations were made to assist in establishing satisfactory treatment methods for small-scale concentrator operations, or to indicate a. method for conserving previously lost mineral values in old tailings, if possible. A discussion of test procedures is included, as it was felt that this would add to understanding the results reported under the several projects. The treatment of scheelite ores has become more or less standardized. Important differences occur in textures of ores from various mining districts. However, and this must be considered when planning ore-dressing operations. In most of the present investigations, only a limited amount of work was done, usually just enough to answer a specific question in regard to a particular ore or concerning local conditions. Two methods of treatment included gravity concentration, magnetic separation, and flotation.

Jan 1, 1952

The following persons were appointed as representatives of this Institute on, the American Committee on Engineering Standards.: George C. Stone, J. W. Richards, Arthur L. Walker. The Secretary presented a request from the Engineering Council that the representatives of the Institute be arranged in the dicier of retirement so that one would retire in 1918, two in 1919, and two in 1920. The

Jan 9, 1917