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By S. Mathur

Oxide particles are commonly used as fillers in plastics, paper, rubber etc. (particulate composites). The successful fabrication of such composites is dependent upon the adhesive strength of the filler particles to the matrix. The compatibility of the matrix and the filler particles is generally enhanced by adsorption of surface modifiers such as surfactants and polymers at the particle-matrix interface. In order to develop a scientific basis for selection of appropriate modifiers it is necessary to understand their adsorption mechanism(s). Specifically, adsorption of polymeric additives is attributed to a combination of chemical and electrostatic interactions, hydrogen bonding and van der Waals forces. Hydrogen bonding has been suggested to be the primary adsorption mechanism for non-ionic polymers. However, a literature survey of Poly(ethylene oxide)(PEO)-oxide system suggested PEO, a non-ionic polymer, to be substrate specific. A systematic study was undertaken to investigate the adsorption mechanism(s) of a PEO on oxide particles. It was determined that strong Bronsted acid sites on the surface interact with the ether oxygen, a Lewis base, of PEO to induce adsorption. In this work characterization of PEO binding sites on oxides is reported and the mechanism(s) of PEO adsorption discussed.

Jan 1, 1997

By Minerals and Materials Analysis Section

During 1996, US mines produced 319 t (10.26 million or) of gold metal valued at $4 billion. At yearend, mine reserves were estimated to be 4.7 kt (151 million oz) of gold metal. Almost all of the production was from western states. Nevada accounted for about 68% of national production. Information for this article was obtained through annual reports of mining companies, US Geological Survey (USGS) databases and other public sources. Table 1 shows production and reserves by mine. It divides the mines into two categories. These are producing mines whose primary product is gold, and producing mines for which gold is a byproduct or coproduct. The mines listed in Table 1 accounted for more than 98% of US gold production during 1996. Except the Daisy Mine, the table does not include mines that produced less than 31 kg/a (1,000 oz/year). The Daisy Mine started production in December of 1996. Nor does it contain mines whose byproduct concentrate is

Jan 1, 1997

By L. Mao

A first-order flotation rate equation was derived by incorporating both hydrodynamic and surface forces involved in bubble-particle interactions. The hydrodynamic forces were calculated using an appropriate stream function, while the surface forces calculated using the extended DL VO theory. The equation was used to predict flotation results as functions of several important parameters such as contact angle, Zeta potentials of air bubbles and particles, and bubble size. The predictions are consistent with experience, and can be explained in view of the various sub-processes considered in the model.

Jan 1, 1997

By W. Lin

When a large area of open gob collapses suddenly, a windblast is produced that can cause considerable damage throughout the infrastructure of a mine. In a few cases, the windblast has been accompanied by ignitions of methane and/or coal dust. This paper describes the conduct and results of laboratory tests involving the compression of mixtures of air, methane and coal dust under a falling weight and while allowing controlled escape of the mixture. The transient responses on pressure and temperature sensors were recorded. In addition to an analysis of those records, the paper highlights those conditions in which ignitions occurred.

Jan 1, 1997

By W. J. Wuest, M. J. DeMarco

The US Bureau of Mines (USBM) recently developed a rock-mass classification system for evaluating the structural competency of bedded roof strata. The system is called the coal-mine roof rating (CMRR), When compiled with the companion Lotus 1-2-3 spreadsheet, CMRR data are a useful tool with applications to longwall gate-road pillar design, safety-hazard mapping and artificial roof-support analysis. This paper gives a review of some applications under actual conditions found in current US mining operations.

Jan 1, 1997

The Porgera mine and treatment plant are located in the Enga Province of Papua New Guinea. Gold in the Porgera deposit is found free and in association with the primary sulphide mineral pyrite. The refractory nature of the gold in the pyrite r

Jan 1, 1997

By Lawrence Devon Smith

"What is Due Diligence?Within the mining industry the term “due diligence” is used to describe a detailed data review, generally in connection with the purchase or sale of a mineral property, the approval of a large capital expenditure, or the borrowing of a large sum of money.The term originates in the requirement of the board of directors of a corporation to “act honestly and in good faith ... and exercise the care, diligence, and skill that a reasonably prudent person would exercise in comparable circumstances” (OBCA, 1994). Furthermore, the law assumes that a corporation (or its board) will have exercised due diligence in the acquisition of an asset and, therefore, knowingly (in the absence of fraud or deceit) will have taken on the liabilities and obligations associated with the asset (Nelson, 1994). This is the familiar “Buyer Beware”.Directors are liable for their decisions except “if the director relies in good faith upon financial statements of the corporation represented … by an officer of the corporation or in a written report of the auditor, or a report of a lawyer, accountant, engineer, appraiser, or other person whose profession lends credibility to a statement made by any such person.” (OBCA, 1994).Hence the importance of reports prepared by professionals. They provide confirmation that the directors have exercised due diligence in the performance of their duties. For this reason these reports are referred to as due diligence studies"

Jan 1, 1997

The sixth Annual RMCMI Mine Rescue Evaluation was held during the 1997 Institute convention at Sheraton Steamboat Resort, Colorado. The Mine Rescue committee, co-chaired by Becki Boam and Gary Cook, is one of 18 committees of the Institute. In 1997 the largest number of teams participated in the program. There were nine: BHP Minerals - La Plata Mine, BHP Minerals - Navajo Coal Co., BHP Minerals - San Juan Coal Co., Bridger Coal Co., The Coteau Properties Co., General Chemical Co., The Sabine Mining Co., Solvay Minerals and Western Energy Co. Professional evaluators who provided challenging scenarios for the 80 participants were Jack Knight of Milton, Florida; Wilson Begay, Chris Saxon, and Gaylon Yazzie all of Western States Security; Mary Bailey, Bailey Associates; Tom Bass, California Department of Corrections; and Art Saenz, BDC. Seven members made up each team plus one or more trainers and represented the states of Montana, New Mexico, North Dakota, Texas and Wyoming. Ten different scenarios were presented during the two day evaluation. Each team was given the pertinent information to solve the problem as they assembled at the site. Mine Rescue families and friends participated as victims providing realistic scenarios to simulate the stress of an actual rescue incident. Each team was unaware of the circumstances until arriving at the various scenes in and around the Sheraton resort. [ ] These teams are providers of prompt rescue and medical care for accident victims at their respective properties. The members act with immediate and professional knowledge to save lives and prevent further injuries. Sponsors who contributed financially to the 1997 program are: Argo Industrial, Antelope Construction, Fisher Safety Supply, Flanders Electric Motor Service, Inc; Intermountain Electronics, Inc.; King Energy Services, Inc.; Rocky Mountain Electric Motors, LS.; TerraMatrix and Triune Inc. On Saturday evening, June 28, a reception was held for all mine rescue participants and spouses who had advance registered for this social event. The RMCMI Board of Directors was invited to attend and meet with the teams. As convention attendees, all mine rescue participants and registered families attended the Monday night country western reception and Bar-B-Q. This was followed by an adult western melodrama. [ ] Glass awards with the RMCMI logo and a Mine Rescue figure were presented at the Tuesday Mine Rescue buffet breakfast to all nine teams, each of which had achieved proficiency at level 3. Captains of the teams pictured below are (from left standing): Ron Neff, BHP-San Juan; Ted Laughline, Bridger, Terry Davis, Coteau; Jim Knutson, General Chemical (from left kneeling): Dan Allerdings, Rosebud; Ron Miller, BHP-Navajo; Jonathan Sorrell, BHP-La Plata and Ray Blaisdell, Solvay. Gary Cook is to be commended for his solo last minute supervision of the Mine Rescue program, due to Becki Beam's unavoidable absence. The teams look forward to the 1998 convention at Snowmass Village Resort, Colorado Thursday and Friday, June 25 and 26.

Jan 1, 1997

By A. M. Alfantazi, M. Boissoneault, D. B. Dreisinger, J. Synnott

Acid mist generation is a major concern in zinc, copper and nickel electrowinning industries and there is a strong environmental drive to control its emission into the work environment. Foaming reagents are typically added to the electrolyte to alleviate this problem. In zinc electrowinning, Licorice and Saponin are examples of foaming reagents used for this purpose. In order for the foaming reagent to be effective, its foaming behavior must be determined. In this work, a test procedure was developed to study the foaming characteristics of various surfactants for use as foaming agents to control acid mist in aqueous metal electrowinning. This new test was termed as "mini-flotation test" and it was used to study the foaming behavior of a large number of reagents in an industrial zinc sulfate electrolyte under simulated zinc electrowinning conditions (gas sparging). In addition, the influence of important process parameters such as current density, electrolyte temperature, reagent addition level and sulfuric acid concentration on the foaming characteristics of the electrolyte for each surfactant were investigated. The results of this study have identified the most important factors that influence foam formation, growth and stability. This method could be used as a process control for reagent addition in the cellhouse by generating a calibration curve for the optimum electrolyte conditions.

Jan 1, 1997

By Eugene F. Casey

The next ten to fifteen years will be exciting ones for the construction industry because three city agencies alone have started or will start, on tremendous expansion programs, the cost of which will exceed a total of four billion dollars. The major portion of this work will be done by the use of tunnelling methods. *Tunnelling is construction by any method of a covered cavity of predesigned geometry whose final location and use under the surface, whose cross-sectional area is greater than two sq. meters. The New York City Transit Authority's expansion program will provide for approximately 52 miles of new subways. The Board of Water Supply has already started on City Tunnel No. 3 which, when completed will provide the City with enough water until the year 2000, and the Board of Water Resources has embarked on a tremendous program to clean up the surrounding waters. Yes, these will be exciting years, particularly when one reads about the new novel exotic methods of rock breaking and disintegration, coupled with the new methods of soft ground tunnelling.

Jan 1, 1997

By A. J. Hendron, L. L. Oriard

INTRODUCTION Controlled blasting is used at some time during most civil engineering projects where there is rock excavation. Controlled blasting is often necessary because the blasting must take place in the near proximity of adjacent structures. In other instances, the blasting is controlled because a smooth perimeter is desired to minimize rock support and overbreak. The construction of tunnels and shafts for subways, rock excavations for foundations and the excavation of road cuts for interstate highways, sometimes require blasting operations which must be conducted in an urban environment. Unfortunately, blasting operations produce unwanted sounds and vibration along with their beneficial effects. Thus, in the writing of specifications for blasting in an urban environment, potential damage to adjacent structures by ground vibrations must be considered, possible damage to windows from airblasts must be considered, potential damage from fly rock must be considered, and the discomfort to people from ground vibrations, airblast, and noise must be taken into account. The contractor or the owner's engineer is faced with determining the maximum weight of explosives which may be detonated without damage to structures on adjacent property. If the weight of explosive is overestimated, the resulting damage to adjacent structures may result in costly losses. But, if the engineer or contractor is too conservative, and the weight of explosive becomes too restrictive, progress of the project may be curtailed and the cost of excavation will increase accordingly. The potential for damaging adjacent property is becoming more important in construction operations today. In the past, the plaintiff had to prove negligence in some states in order

Jan 1, 1997

By Hale C. T, Carnie W. A

Rosebery mine has had over 100 years of mining activity. The reserve has remained static for the last eight years with an expected mine life of six years. A move to rectify this was made in 1994 with the birth of the Deep Exploration Project (DEP). $45 M was committed to drill 100 km of underground exploration diamond drilling and develop 5.5 kin of decline aiming to add 9.5 Mt to the reserves and minimise lead time for development of P and K lenses discovered in the early-1990s. In 1996 this aim was expanded with the objective to build the resource base to 20 Mt by June 2000 allowing the mill to operate at 1.0 Mtpa (0.9 Mt from underground). Preliminary results of the project to-date are outlined and exploration diamond drilling techniques and strategies are described.

Jan 1, 1997

By Satu Strömberg

Four different nickel concentrates were oxidized in a laboratory scale laminar flow furnace in simulated flash smelting conditions. The major nickel- and iron-bearing minerals in the con- centrates were pentlandite, violarite, gersdorffite, and pyrite and pyrrhotite, respectively. Thermal decomposition, ignition and oxidation behavior of nickel and iron sulfides were examined by using optical and scanning electron microscopy. General reactivity of the concentrates was monitored with sulfur removal which was most effective in violarite-based concentrate. Pentlandite-concentrates needed higher experimental temperatures for complete desulfurization and gersdorffite-based concentrate contained 5 - 10 % of the original sulfur even in the most oxidizing conditions studied (1 100°C, 50 vol-% 02). The reactivity of the iron minerals was found to depend on the other minerals present in the concentrate. In this paper, the observed re- action products and mineralogical changes are presented and preliminary conclusions of possible reaction mechanisms of nickel-bearing minerals are discussed.

Jan 1, 1997

The extractive industry has been faced with a situation where there has been no systematic and formalised training and education structure available. Previous structures which were available, e.g. the quarrying diploma and the mining papers as a part of an engineering degree, have suffered the same fate as the Dodo. They are now extinct.   In providing for a training strategy, the past strategies need to be examined and reasons behind their demise examined. This paper examines the reasons for past failures in education and training in the extractives industry, the factors that need to be taken into account in creating an education and training culture, the strategies required, the Government regulations and trans-Tasman agreements, and the quality management which must surround the entire training programme.

Jan 1, 1997

By Zhang Shixun, Wang Xuguang, Zhong Yinting

The Mongol-Russian Joint Mining and Processing Cu-Mo Corporation Erdenet signed a contract with BGRIMM for building a plant to produce 10,000 t/y multitype emulsion explosives by using BGRIMM emulsion explosives manufacturing technology. In order to ensure the realization this contract, we have done a series of studies on the design of technological process and the selection, layout of the production equipment, and made a success.

Jan 1, 1997

By Dewey W. Geary

Nast Tunnel is the first granitic rock tunnel to be excavated by a machine for the U. S. Bureau of Reclamation. The machine has excavated 7500 ft of the tunnel at this writing. There have been a few good performances; 31 ft in 1, 8 hr shift, and 75 ft in a 24 hr period, but generally, progress has been slower than that accomplished in the area with reasonable comparable conditions using conventional excavation techniques. Button cutters, now employed using compression as the means of fracturing the rock, gives an average cutting rate of 3 ft per hr. Disc cutters manufactured by the machine builders were tried briefly but the snap rings holding the discs to the hub failed. However, disc cutting rates of 6 ft per hr were recorded for short periods of time in a competent coarse grained porphyritic granite. The snuck was also considerably larger and more easily handled than that produced by the button cutters. Hughes Tool Co. is working on a disc type cutter and expects to have them on the cutterhead by mid June. LOCATION, DESCRIPTION AND BID OPENING Nast Tunnel is located 2 miles west of the Continental Divide and 39 miles east of the town of Basalt in Pitkin County, Colorado. The outlet portal is in the Fryingpan River Valley at an elevation of 10,000 ft. The tunnel is a 3 mile long, 10 ft diameter gravity flow water conveyance structure and a part of the west slope water collection for the Bureau of Reclamation, Fryingpan-Arkansas Project. The bids were opened July 9, 1970, with 8 contractors submitting proposals. The contractors were given the opportunity to bid

Jan 1, 1997

By John Marshall

Silverton was the queen city of the western mining towns in the early 1900s. Located high in the San Juan Mountains, the town constantly grew and changed. Yet, it was subject to the vagaries and whims of economics, politics and disasters, natural or otherwise. Breweries, smelters and sawmills serviced Silverton's swelling mining population, which reached several thousand at its peak. Two trains a day ran from Durango to Silverton, in addition to trains running from Silverton over the top of Red Mountain on to Ironton. They ran up Cement Creek to the little town of Gladstone and up the Animas River Valley to Howardsville, Eureka and Animas Forks. During these prosperous times, construction flourished. There were plenty of wooden structures, and many of these stand today. The first brick buildings were built by bricklayer Patrick Stanley in 1877. It took quite a while for the first car to arrive. Almost 28 years passed from the coming of the first train to the arrival of the first car. It was brought over 3,840-m (12,600-ft) Stony Pass from Creede, CO, in an incredible journey retold years later by Louis Wyman. "Dad's daydreams were not the idle musings or the fantasies of a mystic," Wyman said. "They had a way of erupting into reality. He advocated and built good roads," he said. "During the summer of 1910, he was up to his sweatband in a project that took in half the state of Colorado. He envisioned an automobile highway, unheard of at that time, running southwest from Denver through the scenic grandeur of the high Colorado Rockies. The road would traverse a thousand miles or more of the state's finest recreational land finally circling back to Denver. Years later, when all of the county roads had been connected, it became known as 'Colorado's Thousand-Mile Circle Route.' Of course, Silverton and the San Juans were bright stars along the way."

Jan 1, 1997

By Hiddlestone D. C

Effective exploration, testing and analysis is essential for good process design and optimisation of coal preparation plants. Coal processing relies on the sizing and washability characteristics of the particular coal to define the most cost effective design to meet the market requirements. Flowsheet development and equipment selection is dependent on the natural quality characteristics of the coal, its physical properties and the value of the final product in its market. The methodology of process selection and the key elements in design are discussed. Coal is consumed in two general markets: ò steaming coal - both domestic and export, and ò metallurgical coal. This paper discusses the typical economic analysis required to evaluate the potential for, and cost benefit of, providing the flexibility to switch coals between markets. A case study illustrates the methodology of process selection in a typical high value metallurgical coal.

Jan 1, 1997

The placer mining industry of the West Coast region of the South Island is based largely around the production of alluvial gold, although other valuable minerals are also present. Since the first major discoveries in 1864-65, reported gold production has totalled around 264 t (8.5 Moz). During the past 10 years, annual production has totalled around 1460 kg (47,000 oz). It is anticipated that gold production over the next three years will continue at a level of 1400-1800 kg.   Annual gold production peaked during 1866 at approximately 17,170 kg (550,000 oz) and has not exceeded 100,000 oz since 1885. This reflects the ease with which gold was won from shallow, rich deposits that were present at many localities. Subsequently, there has been a general decline in the availability of this type of deposit, a trend that will continue in the future. This paper outlines the present state of placer mining in the West Coast region, gives some historical background to the industry and briefly predicts future trends.

Jan 1, 1997

By Steve Collinsworth, Nils Heinke

In 1989, I realized the definite need for change in the Blast Hole Drilling Industry. With over 25 years of experience in dealing with the industry, I am well inGormed and educated concerning the problems that occur in Blast Hole Drilling. After continues interaction with the Drill & Blast Superintendents, Drillers, Purchasing Agents, Mechanics, and others in the field, a basic understanding was developed as to the origins of the main problems that the industry f&s with their drillings programs.

Jan 1, 1997