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By W. Kracht

Frothers are surfactants used in floatation to aid generation of small bubbles. Studying events at the moment of bubble creation is a challenge because of the short time frame. This presentation introduces a novel acoustic approach. The technique has the resolution capable of detecting events that occur within 1-2 ms. The transition from coalescence to non-coalescence is tracked as a function of surfactant concentration and gas rate through the capillary. Results are given for some common flotation frothers and n-alcohols (C4-C8). A stress model is used to give a qualitative explanation to the observed action of frothers on coalescence prevention. Results for salt (sodium chloride) are included for comparison).

Jan 1, 2009

By Russell W. Hunt

The cave man of ages past took his wife-and family from the cave pointing to a fire he had built and beating on his breast said, "Look what I have done". Today man is taking his family back to a cave saying, "Come enter in because of what I have done". At the close of World War II Germany said if they had gone underground one year earlier with more of their operations, the war could have lasted four years longer with perhaps much of Britain devastated. The protection of the home front no longer rests with the soldier in actual combat. The battle will be won at home with the most careful kind of protection against missiles. After Nagasaki-Hiroshima Sir Winston Churchill said in substance "Up to now the Almighty has mercifully withheld from man the knowledge of these terrible weapons of destruction."

Jan 1, 1959

By Bruce Geller

The 2004 Prospectors and Developers Association of Canada (PDAC) conference contained an air of optimism and excitement that has not been seen since 1997. Many segments of the mining industry are alive and well. This is largely a reflection of improved metal prices, themselves due to the strong euro and improvements in Asian economies. Those factors offset higher oil prices, a weaker U.S. dollar and concerns about the Middle East. This report is an overview of the conference. It is supplemented by an examination of conference handouts, abstracts and a few complete papers that are on the PDAC’s Web site www.pdac.ca. Sixty PDAC 2004 abstracts are available at the same site, along with 15 complete papers in PDF format. The conference was held March 7-10 in Toronto, Ontario. It was attended by a record 9,200 delegates from 85 countries. About 8,000 people from 74 countries attended the 2003 conference.

Jan 1, 2004

By Pat C. Hautala, J. R. Hoskins

This is a new era for the minerals industry. Never before has there been more need for effective communication. So said Robert Anderson, chairman and chief executive officer of Hanna Mining Co. He was speaking to the American Mining Congress's Communication Workshop. The question is whether there is enough industry concern to meet the challenge. Anderson observed that increased workshop attendance, in continuing tough times, reflects the industry's concern for communication. But, why were students, faculty, engineers, supervisors, and managers not at the conference? Communication applies to every manager, Anderson said. But he was the only operating manager present. And only one company sent operating supervisors. The remaining conference participants were public relations personnel, generally with nonmining backgrounds. And the program dealt mostly with public relations issues. Role of Communication in the Minerals Industry. It is well known that the minerals industry faces economic, political, and social problems. Economic shifts and foreign competition have created an international minerals industry and an international marketplace. This, in turn, calls for worldwide communication. Other factors effecting communication are: • Governmental protectionism as well as regulatory reforms call for increased interaction with governing officials. • Changing social values have created environmental issues and anti-industry attitudes. This intensifies the need for improved public relations. • Traditional work values are shifting towards self-actualization and humanistic movements. The work force is better educated and more informed. Employees demand more satisfaction, equality, and job autonomy. • The mining industry's task of managing its human resources is complicated by layoffs, job uncertainties, and bleak outlooks concerning employee morale and motivation. Technology and Information for a New Era As noted, this is a new communications era, one propelled by technology and information. Technology has led to reduced demand for raw materials by developing substitutes. Copper demand, for example, will never fully recover. Copper cables are replaced by fiberoptics; copper transmission lines, with aluminum. Technology has shifted the US from traditional to high tech and service industries. The speed, frequency, and scope of information transmission have greatly increased. But the most significant characteristic of this information is not the pace of advancing technology. It is the dramatic increase in the importance and frequency of our personal transactions. Knowledge has replaced raw materials and capital as the strategic resource. Information has replaced energy as the transforming resource. And the game against nature has become an interpersonal game (D. Bell, Post-industrial society, Physics Today, '76). In Megatrends, John Naisbitt says that information will soon double every 20 months. So, professionals will become "information workers." And communication will be the life channel of the information age. Thomas Wolfe said you can't go home again. Hanna Anderson said we are, indeed, facing a new day. It will never again be "business as usual." We must move into the information age with the rest of society. We cannot trust that the world will continue to rely on our products. Nor can we place the responsibility and control for problems and solutions outside the minerals industry. Improved communication is not a panacea. But, Anderson said, it is critical to the minerals industry. What is Communication? The word communication is overused. It is applied to every aspect of our lives. Satirist Tom Lehrer got sick of hearing about the need to communicate. He said, "It seems to me that if someone is having all that trouble communicating, the very least he can do is shut up!" Obviously, we cannot follow that advice (though we might wish that some others would do so). Communication is always going on. It is inevitable. Yet we have many misconceptions about com-

Jan 1, 1985

By James R. Walsh

While flue gas scrubbing with alkaline solutions is one of the oldest methods of removing SO2 from flue gas, a satisfactory scrubbing system for this application, which is both technically and economically viable, has yet to be developed. Interest in alkaline scrubbing has continued because of its basic simplicity and comparatively low capital cost. Drawbacks of alkaline scrubbing are the tendency for accumulation of solids to plug the system, scaling, corrosion and erosion problems and the need to dispose of large quantities of waste. Discussed are instrumentation loop applications to a 90,000 cfm alkali scrubbing test facility, the process problems the instrumentation engineer faces in. selection of equipment, the performance of the instruments selected and the problems encountered during start-up. The Test Facility incorporates centralized electronic process control with a digital data acquisition system provided to log process variables and print off normal (alarm) conditions. Flue gas SO2 content is measured by ultra-violet analyzers and analysis of the total gas stream is by gas chromatographs.

Jan 1, 1973

By J. M. Manka

American mining companies operate many drum hoists that hoist from various depths with varying payloads. This paper will review the procedure of selecting optimum wire rope constructions for these existing hoisting installations. Selection for proposed installations along with recommended hoisting parameters will also be presented. To achieve this optimum rope performance, preventative and corrective maintenance procedures will be reviewed along with examples of rope problems and their causes.

Jan 1, 1992

By Koji Nakanishi, Masayoshi Karasawa, Yasuhiro Morimoto

"Shin-Yokohama station (tentative name), one of the station of the Sotetsu - Tokyu through line (ST line), is under construction by the OPEN – CUT method. The Underground Soil–Cement Steel Diaphragm Wall is implemented as an earth retaining wall. This earth retaining wall is utilized as a main body of a subway station. It is the first time to utilize this earth retaining wall as the main body. There are two difficult issues for this project. One is that this station is planned under busy major road and there are many underground utilities, for example, an electrical transmission line. Because of that, construction area is limited. The other is that this station is located in a thick soft clay layer. This layer has a high risk of consolidation settlement because of draining during main excavation. Thus, high water tightness is required for this earth retaining wall. This paper reports design and construction methods for the Underground Soil–Cement Steel Diaphragm wall introduced as a part of the body of the subway station.1. OUTLINE OF SHIN-YOKOHAMA STATION 1-1. Location and structure of Shin-Yokohama Station Shin-Yokohama station is an intermediate station on the ST line connected to the Tokaido-Shinkansen bullet train, the JR-Yokohama line and the Yokohama Municipal Subway. Access to Tokyo and the Tokaido- Shinkansen from the eastern part of Yokohama city will be improved by this project. In addition, the number of estimated passengers of this station is one hundred thousand people/day because a soccer stadium (Nissan Stadium: 72,000 people), a huge indoor arena and a hotel are located in this area. This station consists of 4 stories and 3 spans (Max width; 29m, Depth; 33m, Length; 325.5m). Completion image is shown in Figure 2. Generally, stations have 1 platform and 2 trucks. But this station has 2 platforms and 3 tracks because some of ST line trains return at this station and a train deadheads from Hazawa station to this station in an emergency. This station is planned as 4 stories underground station, and the platform is on the lowest story. The reason why this station is in such a deeper position is to prevent the alignment from interfering with the Yokohama Municipal Subway station and foundation piles for bridge piers existing along the alignment. Even under the constraint conditions, earth covering should be shallow as much as possible. As a result, the tunnel edge is very close to the foundation pile, and the gap is only about 2m (Figure 3). In addition, passengers will be able to change trains easily from the ST line to the Yokohama Municipal Subway or vice versa at this station."

Jan 1, 2016

By Jim Dunn

For decades many of us who are associated with the mineral industry have tried to show the public its economic and strategic importance. Some of the mineral industry's proponents have been politically powerful figures and have been widely quoted. Yet, as measured by public opinion, legislative support, or almost any other standard, our efforts have been inadequate. It is apparent that a set of environmental beliefs that discredit industry, firmly held by a number of idealistic persons, has had wider coverage in the media and in schools than has the mineral industry's message. Although the fervor of our idealistic friends is often unfounded and, their stands unscientific, they must be considered seriously. Unless we address the issues in terms the idealists will understand, the mineral industry will have little influence on them or on the general public. A. striking thing is that, quite often, translation of idealists' views into action has been counterproductive. The reason is obvious. Excessive amounts of money and energy have been spent on relatively minor problems. The common result is that larger problems have been created. It may be possible to help anti-industry idealists understand their own dependence on minerals, and thus render their views more realistic, if they are shown more effective ways to reach their stated goals. If those goals can be shown to be held in common by all sensitive human beings -- including those in business and industry - the dialogue becomes one of how to achieve common ends. Individual mining companies acting by themselves have little possibility of success, and companies working in unison through trade associations have not been successful. Further, it is unlikely that industry in general can be successful in changing minds unless it seeks outside help. But friends among those who influence public opinion have been hard to find. Historically, help from media has proven difficult to get. Nor has enough help from educators been forthcoming. Yet, a war is going on in the technological, philosophical, and political trenches, even though much of the public is not aware of it. For the first time in years, there is row a significant and growing number of eloquent and brilliant thinkers on the side of free enterprise and industry, many of them environmentalists, but without the anti-industry mind-set. They have had remarkably little help from the private sector or even from the present administration. Industry may do far more for itself in the long run by encouraging these brave but bruised individuals and their organizations than by trying to work alone. These friends of free enterprise are working against a seemingly stacked deck relative to much of the media, the bureaucracy, and the educational system. However, despite their problems, their success to date has been remarkable. With more cooperation from industry they should do even better.

Jan 1, 1987

By J. L. Vanderbeek

Investigations have been conducted at Chino Mines Company into the effect that SAG mill recycle material (critical size) exerts on SAG mill throughput and specific energy requirements. Tests were conducted on the laboratory, pilot, and plant scales, to evaluate the merits of alternative treatment options. Removing critical size material from the SAG mill circuit has been shown to improve new feed rates by 34% with a reduction in specific energy (kWh/ton) of 33%. Test results obtained to date are presented.

Jan 1, 1985

By Günter Huber, Bruno Mattle, Helmut Westermayr, Daniel Spöndlin, Max John, Nejad Ayaydin

PROJECT DESCRIPTION Alignment The Strenger Tunnel forms part of the S16 four-lane expressway between Landeckand Bludenz. The construction of this important East-West connection started in 1973with the Arlberg Road Tunnel as its key constituent. Beginning in 1992, solutions for the section between Pians and Flirsch were investigated. Efforts to conserve nature and to avoid potential avalanche and landslide areas led to a solution detouring the villages in the Stanz valley. The starting points were predetermind by the intersections at Pians in the East and at Flirsch in the West. As a result of the expected traffic load and the comparatively high gradient of 2.9%, both one-way, two-lane tubes were constructed at once. The north tube is 5.851 m long, the south tube 5.775 m, see Figure 1. Layout of Tunnel Cross-Section The tunnel cross-section was determined by 2 × 3.75 m wide, 4.70 m high roadways, two sidewalks and sufficient space for two fans above the clearance

Jan 1, 2005

Introduction Aggregate mining impacts on water resources are a source of concern to local governments. To evaluate those impacts, the Minnesota Department of Natural Resources conducted a four-year study at three gravel pits (two alluvial and one beach-ridge) and five quarries (flat-lying Paleozoic limestone). This research provides the first comprehensive look at aggregate mining impacts on ground-water systems in Minnesota. The results will be used by government officials making permitting decisions about aggregate operations and by responsible owners of aggregate mines as they plan their operations to avoid conflicts with neighbors and with resources dependent on ground water and surface water. Natural aggregate (crushed stone, sand, and gravel) is a vital part of our economic infrastructure in Minnesota. Aggregate is used for road and bridge construction and in a variety of building materials. In 2003, the value of construction sand and gravel and crushed stone in Minnesota was approximately $245,000,000. As Minnesota’s economy continues to expand, the demand for aggregate will continue to grow. Sand and gravel pits are located in every county in Minnesota. In 1990, the Minnesota Department of Natural Resources, Division of Minerals (DNR Minerals), estimated the number of active and inactive operations at 1500 with the view that this number was likely too low. Quarries for mining limestone, dolomite, sandstone, and hard rock (granite and quartzite) are found in 34 counties. A 1990 DNR Minerals inventory found 165 active operations, 88 percent of which were limestone quarries (Nelson and others, 1990). That same inventory counted 1,367 inactive operations, 70 percent of which were limestone quarries. Aggregate mining is an extractive use of resources: mining alters the landscape and its natural hydrologic system. When a new pit or quarry is proposed or when an existing operation needs to expand, local governments and citizens typically have many questions about the impacts mining might have. Local governments, which are responsible for reviewing these operations, rarely have the budgets to hire experts to evaluate potential impacts of quarry and gravel pit proposals. The Minnesota Legislature’s Aggregate Resources Task Force identified that local government units (LGUs) often lack the expertise to assess ground-water models (Southwick and others, 2000).

Jan 1, 2007

By Jay Hilary Kelley

A ventilation system is described using dual aircourses: one zone occupied by working personnel, the other at the active working face. The two zones are separated by a partition or Shroud. The occupied zone to the rear of the face zone is ventilated adequately but with considerably less air because little gas, dust, or fumes are present. The face excavating zone is sealed and maintained at slightly more negative pressure preventing dust and gas generating from within to escape. Explosive mixtures within the face zone is rendered non-explosive by the introduction of inert gas therein. Each zone is vented separately to the outside of the mine. Because less total quantity of air is required for human breathing, etc, the total ventilation system can be drastically reduced in tan capacity, development entries, and air shafts, -- a great savings in costs.

Jan 1, 1991

By Chee Theng

"Mineral processors know you can put in the best technology in the world but it won’t work optimally without the support of the operators. Conversely, you may have complete operator support but won’t get top results without the right technology. When the two come together, the returns can be phenomenal.The first day of talks at the 68th Annual Colorado MPD Conference, held April 26-28 at The Broadmoor in Colorado Springs, covered the ground on these industry wisdoms.Coming together as a team“Think of the people, not just the lab and the numbers. That makes all the difference,” said Dee Kippers, of FMI Henderson Mine, in her talk on “Process optimization during a market downturn (A Moly MacGyver story).” Kippers told an entertaining story of the journey she and her team took in tackling the issue of an annual spike in iron content in the product at Freeport- McMoRan’s Henderson primary molybdenum mine near Empire, CO.As the metallurgists tried one thing after another — cranking up the iron depressant, adjusting pH with sodium hydroxide and hydrated lime, modifying reagent levels — Kippers found that when she shared her results with the operators, communicated with them on what she was doing and got their input, they were more willing to work with her, and more understanding and supportive of her efforts.The results make the case for getting people on board and coming together as a team. The cost savings from their optimization efforts, with little capital investment, have been “enough to cover the annual salaries of our metallurgy department and then some,” Kippers said.Considering the environmentDavid Lemieux, of Dundee Sustainable Technologies (DST), talked next on “Cyanidefree process for gold extraction,” presenting the results obtained from a demonstration campaign of the company’s novel chlorination process for gold extraction and associated arsenic stabilization process. Developed at an investment cost of C$35 million, they are ready for commercialization, having been demonstrated on the laboratory, pilot and demonstration scales.The DST process is differentiated from the Plattner chlorination process, which was in use from 1851 to 1916, by moderate process conditions of atmospheric pressure and ambient temperature — the result of using sodium hypochlorite solution, or bleach, instead of direct injection of chlorine gas — and new, cheaper materials of construction, such as polymers, plastics, fiberreinforced plastics and Teflon, resulting in lower capital and operating expenditures."

Jan 7, 2018

By K. Ueda

Lead concentrates from Kuroko (black ore) mines, which contain Cu 4 ? 7%, Pb 55%, Zn 3 - 7%, As 0.5 - 0.9% are treated by hydrometallurgical process in order to smelt the product by electric furnace smelting together with other lead resouces from Kuroko. The hydrometallurgical pretreatment involves sulfuric acid leaching at first stage, ferric leaching at second stage. This paper describes the short history of lead recovery from Kuroko and the performance of laboratory test, pilot plant and commercial operation.

Jan 1, 1982

By Yoginder P. Chugh

About 65% of the U.S. coal production (835 n tons was surface mined. A similar proportion of the Illinois basin's production (112 m tons) is also surface mined. The state of Illinois is the third largest producer of surface mined coal in the United States, after Wyoming and Kentucky. The Illinois coal basin encompasses Illinois, southwestern Indiana, and western Kentucky, as shown in Figure 1 (dotted lines). The estimated surface mineable coal resources in the basin amount to about 27 billion tons, and about 69 m. tons of coal is surface mined annually (Tab1e I).

Jan 1, 1981

By Y. H. Zhan

A new P(MAAA) latex was developed and used in separation of ultrafine apatite from calcite and silica by means of selective flocculation. The latex was found to flocculate selectively apatite from apatite/calcite and apatite/silica mixtures in the presence of sodium tripolyphosphate and sodium silicate over a pH range from 9.1 to 9.4. The separation of apatite from calcite was more selective with sodium tripolyphosphate, while the results of the separation of apatite from silica were better when sodium silicate was used. In the apatite/calcite system, 90% apatite recoveries into a concentrate containing 34% P2O5 were possible in the presence of 4 mg/l of sodium tripolyphosphate at a latex dosage of 2.2 kg/t. In the apatite/silica system, 80% of apatite could be recovered into a concentrate containing 33% P2O5 in the presence of 20 mg/l of sodium silicate at a latex dosage of 1.1 kg/t. Deposition tests were used to study the interaction between the latex and the mineral surfaces. The results revealed that deposition density of the latex on apatite was higher than on calcite; the differences between the deposition onto these two minerals were higher at pH 9.2 than at 7.2. The results point to the stronger interaction between the latex and apatite surface when compared with the latex-calcite interactions.

Jan 1, 1998

Barrick Gold plans to have four new gold mines in production by 2006. Together, the mines would increase the company’s output by 40 percent. The projects include Veladero in Argentina, Alto Chicama in Peru, Cowal in Australia and Tulawaka in Tanzania. All of them are scheduled to begin production between the first quarter of 2005 and the first quarter of 2006. They are expected to drive Barrick Gold’s growth profile to a target of 211.5 to 217.7 t (6.8 million to 7 mil-lion oz) of gold production in 2007. The company’s projected output for 2004 is 152.4 to 155.5 t (4.9 million to 5million oz) in 2004. Overall, higher production and lower costs are expected in the early years from the new mines.

Jan 1, 2004

By Vern Miller

The Bureau of Mines developed a detector for controlling sorting devices to separate the copper-bearing fragments from the barren portion of Michigan native copper and western porphyry copper ores. A successful sorter could be used to preconcentrate the ore and eliminate costly hoisting or hauling of waste. An induction balance unit was developed and used in sorting tests on crushed sized -1+1/2-inch (-2.5+1.3-cm) ores from the Kingston (0.9 pct CU) and Centennial (1.6 pct Cu) mines of Upper Michigan. Concentrates of 4.0 pct and 7.5 pct Cu, respectively, were obtained at recoveries of 85 and 80 pct of the copper in the feed. Eighty percent of the sorted ore was rejected as tailing. Sorting larger fragments improved the separation efficiency. Tests on -4+2-inch (-10+5-cm) sized Kingston (1.6 pct Cu) and Centennial (2.1 pct Cu) ore samples yielded concentrates of 4.3 and 4.5 pct Cu, respectively, with corresponding recoveries of 92 and 91 pct. About 60 pct of the sorted ore was discarded as tailing. Porphyry copper sulfide ores also responded to electronic sorting but at a lower separation efficiency. Sorting response was affected by the degree of segregation.

Jan 1, 1976

By William Hustrulid

INTRODUCTION The Idarado mine lies high in the San Juan Moun¬tains on the divide between the Uncompahgre and San Miguel Rivers and consists of a consolidation of a number of old and prominent mining properties through which course some famous and very produc¬tive veins. Among the better known are the Smuggler, Tomboy, Montana-Argentine, Black Bear, Liberty Bell, Virginius, Flat, Barstow, and Japan, as well as many others. Most of these veins have been extensively mined over the past century and in the last three decades the Montana-Argentine and Black Bear veins have been the backbone of the Idarado mine; therefore, the descrip¬tion of the veins is limited to them. Access to the mine is through either the Treasury tunnel, whose portal is below Red Mountain Pass on US Highway 550 at an elevation of 3244 m (10,643 ft), or the Mill Level tunnel entrance 3.2 km (2 miles) east of Telluride, CO, at an elevation of 2761 m (9060 ft). The Treasury tunnel intersects the Black Bear vein 2643 m (8670 ft) from the portal and the Mill Level tunnel intersects the Argentine vein 2179 m (7150 ft) from the portal. Mining is by shrinkage stoping from slusher sublevels. The size of the scope blocks varies somewhat, but the standard size is 67 to 76 m (220 to 250 ft) long and 61 to 76 m (200 to 250 ft) high. The mine ranks either first or second in Colorado in yearly production of gold, silver, copper, lead, and zinc. It is 9.6 km (6 miles) from the Red Mountain plant to the Pandora plant, via interconnecting drifts and raises. There are engineering offices at both plants as a matter of convenience. The Red Mountain plant in¬cludes the company general offices, warehouse, carpen¬ter and machine shops, and mine change room. The Pandora plant consists of the mill and assay office, ma¬chine shops, and mine change room. The flotation mill has a capacity of 1632 t/d (1800 stpd), making a bul¬lion product and separate concentrates of lead, copper, and zinc. HISTORY OF THE MINE The Montana-Argentine vein was first extensively worked by the Tomboy Gold Mines Co., Ltd., a British concern. This company mined the stoped areas above the Ophir level between 1910 and the late 1920s and most of the stoped areas above the 2100 level between 1900 and the late 1920s. Gold was the principal ore metal mined. The area between the Revenue and Ophir levels was mined chiefly by the Revenue Mines Co. between 1900 and 1910. The ore was worked from the Revenue tun¬nel, which portals in Canyon Creek. Gold and silver were the chief metals recovered. The stopes between the 1700 and Revenue levels, as well as some higher stopes, were mined by Telluride Mines Inc. during the 1940s. The Mill Level tunnel was driven by that company from 1945 to 1948. Lead and zinc then became economically more important than the precious metals. In 1953, Idarado purchased Telluride Mines, which merged with the parent company in 1956. The Black Bear vein was first extensively worked by the Black Bear Mining Co. in the 1900s and by the Colorado Superior Mining Co. from about 1914 until snowslides at the mine camp [altitude 3750 m (12,300 ft)] terminated the company's operations in 1924. Leasers operated at intervals until 1934. The Treasury tunnel, formerly the Hammond tunnel, had been started before 1900 and reached the 1646-m (5400-ft) mark early in the 1900s, at which time activity lagged until the late 1930s. In the early 1940s, Idarado extended the Treasury tunnel from its heading at 1646 m (5400 ft) to the Black Bear vein and established a raise connec¬tion with the 600 level, the lowest level in the old mine. Since completion of initial work in the mid-1940s, systematic development of the mine, both in the driv¬ing of new headings and the utilization of older open¬ings, has resulted in the present extensive network of workings. GEOLOGY Introduction The oldest rocks of the area are the Precambrian metamorphic rocks, the Uncompahgre formation which are massive quartzites, some phyllites and slates, and dolomitic or limestone beds. West-dipping Paleozoic and Mesozoic strata lie on the Uncompahgre formation. These units are separated by a major angular uncomformity from overlying, essentially horizontal, Tertiary formations that include the basal Telluride conglomerate and several thousand feet of overlying volcanic rock. Intrusive rocks, mostly Tertiary in age, are common in the area, and are in the form of dikes, stocks, and sills. Dikes are very closely associated with some of the ore veins (Mayer). Description of Veins The Black Bear and Argentine veins range from 0.6 to 7.6 m (2 to 25 ft) in width, but in most places are 1.5 to 2 m (5 to 7 ft) wide. They vary in character from a well-defined tabular structure between sharp "frozen" walls, or gouge seams, to an irregular zone of quartz and quartz-sulfide stringers. Many gouge seams within the veins make the veins blocky and loose. Common gangue minerals in the veins include quartz, pyrite, rhodonite, chlorite, sericite, clay minerals, epidote, calcite, adularia, rhodocrosite, fluorite, and specularite. Quartz constitutes 60 to 70% of the veins and varies widely in character, ranging in color from clear through white, gray, and green, to amethyst. Chlorite, sericite, the clay minerals, and fine-grained quartz are common alteration products of the vein walls and of wall rock fragments in the veins. Epidote is an altera¬tion of the dike or, less commonly, of tuff-breccia. Calcite, adularia, fluorite, and rhodocrosite, which are wide¬

Jan 1, 1982

By S. D. Bechtel

Bechtel Civil and Minerals, Inc., one of the Bechtel group of companies, is a large engineering and construction firm that services the mining industry, among others. The firm's head, S. D. Bechtel Jr., comments on how his E&C company is dealing with the recessionary economy. First, he offered a historical perspective. About a half century ago-in the middle of the Great Depression-W. A. Bechtel and several business partners drew up a fixed price bid to build the Hoover Dam. At that moment in history, the W. A. Bechtel Co. was a modest success, but the times were troubled and uncertain. Money was scarce and a lot of contractors across the country were one project ahead of bankruptcy. The bid for Hoover was a make-or-break proposition for Bechtel, and it turned out successfully. The Hoover Dam was a no-frills operation in an isolated and harsh environment. There was plenty of hard work, long hours, and not many amenities. Controlling costs was critical. Everyone knew what had to be done, and why and what the consequences were. Today's Challenge Bechtel is now a bigger, more complex organization whose management views the current economic recession as a challenge to be met in much the same way W. A. Bechtel met the challenge of the Hoover Dam: by pulling together with a sense of purpose and direction. In many respects, Bechtel's situation today has a number of parallels to that which faced my grandfather. The company is eminently successful, but times are tough and there are plenty of signs that they could get tougher. My grandfather bet on the Hoover Dam to insure the future health of his company and I think we can work together again in that same tradition, make some tough decisions together, and the company's future can be just as promising. The first and most important requirement is to make certain that everyone understands the situation. The Bechtel group of companies are in an excellent financial position now. Its workload hit an alltime high in 1982 and it is well positioned in its principal markets. But the next two years may be critical for the company. Traditionally, Bechtel's work load lags behind general developments in the economy. Although many of its clients continue to suffer serious business difficulties, Bechtel is only beginning to feel the impact. The worldwide market for basic metals remains soft; relatively low prices and abundant supplies of oil and gas have flattened the petroleum market and made once promising synfuels projects economically unattractive; utility clients are still caught in the vise between overregulation and escalating costs. And persistently high, long-term interest rates have made capital investments expensive and difficult to justify. The company maintained a healthy workload through 1982. In some areas it has had little new work and consequently has been forced to lay off some staff as projects have been canceled or concluded. In other areas new work has tided the company over and more people have been hired. But new work bookings have fallen off, creating some uncertainty for the near future. 1983 requirements are clear, although seemingly contradictory. Belt tightening and cost reduction are necessary for Bechtel to remain healthy and competitive, enabling it to handle a possible further downturn with a minimum of turmoil and dislocation. At the same time, we need to allocate resources and funds in areas that will keep us positioned for the turn-around marketplace.

Jan 2, 1983