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By Renee Fippin

INTRO PAGE

Jun 13, 2021

By Jesse Salai, Colin Sessions

INTRO PAGE

Jun 13, 2021

By Dave Dorfman, Ben DiFiore

INTRO PAGE

Jun 13, 2021

By S. McMurray

INTRODUCTION Towards the end of the 1890s the attention of a prospector by the name of Thomas Cullinan was drawn to the occurrence of alluvial diamonds east of Pretoria. Persistent prospecting work by Cullinan led to the loca¬tion of the source of these diamonds-a kimberlite pipe on the Elandsfontein farm. Cullinan eventually acquired the property in 1902, and during an extensive evaluation program outlined the largest diamondiferous pipe in South Africa on which the Premier mine was established. Worldwide attention was drawn to this mine in 1905 when the Cullinan diamond, which weighed 3106 carats and is by far the largest gem diamond ever discovered, was recovered. Premier mine operated with varying success until 1932 when the worldwide depression forced it to close. In 1945 the mine was reopened and since then has been a major producer of gem and industrial diamonds. During the early 1950s exploratory drilling revealed that below the 370-m level the pipe had been completely cut off by a younger gabbro sill. This sill has created major mining and metallurgical problems but the existence of vast reserves of high grade ore below it justi¬fied the establishment of virtually a new mine below the sill. Detailed planning of below-the-sill mining is nearing completion and the development of the first mining block (the L1 block) is well advanced. A full discus¬sion of this block follows. GEOLOGY OF PREMIER MINE Pipe Morphology and Country-Rock Geology As can be seen in Fig. 1, Premier mine is an elon¬gated oval shape with a long axis of 900 m on the surface and a short axis of 450 m. The pipe has a surface area of 32 hectares which decreases progres¬sively with increasing depth, so that 500 m below the surface the area is reduced to 22 hectares. The contact between the kimberlite and the surrounding country rock is sharp, with an average angle of dip of 1.48 rad (85°). From the surface down to approximately 350 m, the country rock is a felsite which grades downwards into a norite. In general both rock types are hard and massive, the felsite in particular being poorly jointed. This characteristic combined with other factors results in an extremely stable open pit, and near-vertical side¬walls are currently being maintained. The norite in general is competent but is heavily jointed in some areas resulting in very blocky ground which creates localized tunnel support problems. In the southeastern area below the sill a zone of highly altered and very unstable norite, which has also created localized sup¬port and development difficulties, lies adjacent to the pipe contact. Kimberlite Geology The Premier pipe is a complex multiple intrusion which contains in the region of 15 separate types of kimberlite, most of which are volumetrically insignifi¬cant. On a simplified basis three major types can be identified which correspond to three separate phases of intrusion. They are: Brown Kimberlite: This represents the first phase of intrusion and now occupies the eastern part of the pipe. In plan the brown kimberlite has a crescentric shape resulting from the intrusive relationship with the younger gray kimberlite which lies to the west. The brown kimberlite increases in relative area with increas¬ing depth which is a favorable factor for future mining operations since this kimberlite is the richest area of the mine, having an average grade of 70 carats/ 100 t. Below the sill this rock disintegrates extremely rapidly when exposed to air or water, to form a fine gravel-like material. This characteristic is due to a high montmorilonite clay content. As is common with clay minerals of this type, water can be absorbed into the crystal lattice with a resultant increase in volume which causes the physical decomposition of the rock. The presence of this decomposing kimberlite was a major factor governing the choice of a mining method, as well as development and tunnel support techniques. Gray Kimberlite: This is the most abundant type and represents the second major phase of intrusion. The diamond content is variable depending on the amount of waste rock dilution, and in general the rock is stable and non-decomposing. At the time of formation of Premier, the surface rock type was Waterberg quartzite, a rock formation which has subsequently been removed from this area by erosion. The explosive extrusion of the gray kimberlite caused extensive brecciation of this rock and while the kimberlite was in a mobile state huge masses of quartz¬ite, amounting to tens of millions of tons, slumped into the pipe. This quartzite became concentrated in the central area of the mine and has been a major mining problem throughout the history of Premier since, due to the irregular distribution of the quartzite, effective selective mining has never been possible. The quartzite is therefore extracted with the ore and has a significant dilution effect on the overall grade. Black Kimberlite: In the western part of the pipe a circular, pluglike body of kimberlite is intruded into the gray kimberlite. This plug consists mainly of a hard, dark-colored rock known as black kimberlite, but also contains a number of minor kimberlite variet.ies as well as nonkimberlite carbonate dikes. The Gabbro Sill The sill averages 75 m in thickness and within the confines of the pipe consists of 52 million t of rock. On average the major dip is 0.34 rad (20°) to the northeast which is across the short axis of the pipe, the range of dip being from near horizontal up to 0.52 rad (30°). Due to the pronounced dip, the sill is encount¬ered over a vertical distance of 175 m with the highest upper contacts on the 355-m horizon and the lowest bottom contact on the 530-m horizon.

Jan 1, 1982

By K. Kuhnhenn, G. Prommersberger

General aspects In Germany, swelling rock is mostly found in the keuper formation. Keuper is a sedimentary rock formation of varying composition. It mostly consists of fine or medium layers of clay/silt/marl/dolomite stone with intercalations of gypsum or anhydrite in strips or nodes. After disintegration of the top layers and tectonical incidents, the gypsum level, i.e. the upper [ ]

Jan 1, 1989

By Gregory Beckstrom

"During a year of challenges in the mining industry, two groups collaborated Aug. 17- 20 for a joint conference on industrial minerals of the Upper Midwest. Hosted in Minneapolis, MN, the 4th Annual SME Twin Cities technical conference and the 51st Annual Forum on the Geology of Industrial Minerals (FGIM) drew attendees from throughout the United States and Canada.Highlights of the event included a one-day field trip on Aug. 17 to a crushed stone and gravel mining and processing operations near the Twin Cities, followed by a visit to a historic mine tunnel within the St. Peter sandstone formation. The latter was used as a speakeasy during America’s prohibition era. A two-day field trip on Aug. 19-20 made stops in central and northeastern Minnesota at a granite quarry and processing plant, a peat harvesting and packaging plant, an iron mine and taconite processing plant, and a silica sand storage and loading operation. In a nod to one of Minnesota’s celebrated luminaries, the group also stopped in Hibbing to visit the boyhood home of Robert Allen Zimmerman, better known to the rest of the world as Bob Dylan.A full-day technical program featuring talks on environmental impacts of silica sand mining, regulatory updates, mine land reclamation and methods for identifying construction material failures (alkali-silica reaction) was bookended by the two field trips.According to Minnesota state geologist Harvey Thorleifson, the keynote speaker of the technical program, “This joint SME and Forum on the Geology of Industrial Minerals conference is a reflection of the important role of the mining industry in society, of the important role that partnerships play, and of the prominence of industrial minerals on the Twin Cities region and iron ore on a national scale.” He added, “While this is a tough year for the mining industry in the region, we are confident in the strength of the profession and the industry in the medium term, as we anticipate a superb SME national conference in Minneapolis in 2018.”"

Jan 1, 2015

By Rudolf Kvapil

INTRODUCTION Sublevel mining is a mass mining method based upon the utilization of gravity flow of the blasted ore and the caved overlying waste rock mass. As with any other mining method, sublevel caving has advantages and dis¬advantages which must be carefully considered and evaluated. The major advantages of sublevel caving are dis¬cussed as follows: Because all of the mining activities are executed in or from relatively small openings, sublevel caving is one of the safest mining methods. Drifts, which are the pri¬mary working places, are distributed in a uniform pat¬tern on all levels. Normally the maximum dimensions of the sublevel drifts are about 5 m wide and 3.7 m high. The transportation drifts can have the same section, or the height may be increased to about 4.5 m when trucks are loaded in the transport drifts. The stability and safety of such drifts in competent rock can be easily controlled by smooth blasting or by a combination of smooth blasting with shotcreting. In less competent rock masses, stability can be achieved by combined reinforc¬ing, for example, by a combination of smooth blasting, shotcreting, and rockbolting. The major mining activities can be broken down into three groups: drifting and reinforcing; ore fragmenta¬tion, i.e., production drilling and blasting; and ore draw¬ing, loading, and transportation, and all are relatively simple. Because of the repetitive nature of the mining system, one can standardize almost completely all min¬ing activities. This means that a high degree of work efficiency can be achieved. Because the components of mining production in sublevel caving can be standardized, a high degree of mechanization is possible. In modern sublevel caving the sections of drifts and tunnels are sufficiently large to allow the introduction of large trackless mining equip¬ment. The advantages of a trackless system can be then broadly utilized not only for direct mining but also for all services, including the transportation of mining per¬sonnel to the working place. The flexibility of mining is very good. Standardiza¬tion and specialization of mining activities and equip¬ment on separate levels (lower level or levels in de¬velopment, upper level or levels in production mining) together with the trackless system yield a high degree of flexibility. This allows a rapid start-up of mining and good flexibility in making production rate changes. The method lends itself to good work concentration, organization, and working conditions. Normally, on the lower levels, various phases of development are under¬way. Upper levels are in various stages of extraction. Therefore the work can be easily organized into a sys¬tem which excludes interference between mining activi¬ties. Safety of mining (in small dimension openings), good work organization, high mechanization using large modern mining equipment, etc., comprise very good working conditions. Naturally such a system enables a high work concentration and rationalization of separate specialized mining activities and therefore mining by sublevel caving can be effective and relatively in¬expensive. The major disadvantages of sublevel caving, on the other hand, are: There is a relatively high dilution of the ore by caved waste. Various types of ore loss can occur. When the ex¬traction limit (that point yielding the maximum accept¬able amount of dilution) is reached, the remaining highly diluted ore represents an ore loss. Some ore is lost in passive zones located on the level of extraction between the active zones of the gravity flow. Part of the ore from these passive zones can be recovered together with ore extraction on the lower sublevel, but some un¬diluted and often not fragmented ore located in passive zones above the plane of the footwall is lost. In gen¬eral, these losses are larger as the inclination of the ore body and the footwall is reduced. A relatively large amount of development is re¬quired. This includes transport drifts, usually located in the footwall waste rock on each sublevel, and sub¬level drifts, which connect the active mining areas to the transport drifts and as a result are partially in ore and partially in the waste rock of the footwall. The waste rock length increases as the inclination of the ore body and footwall decreases. It also includes orepasses, used for transport of the ore or waste from the separate sublevels downward to the main haulage level, and normally driven in waste; and inclined drifts or tunnels, which provide a connection for the trackless equipment between the main haulage level and the separate sublevels and are driven in waste. Finally there is the de¬struction of the surface through subsidence. To maximize the ore recovery, minimize the dilu¬tion, and achieve a high efficiency of mining by sub¬level caving, good data regarding the gravity flow pa¬rameters for the blasted ore and the caved waste are of utmost importance. The exact type and amount of data required depend upon the purpose and needs of the study. For the first feasibility study, it may be sufficient to utilize the data from other sublevel caving operations with similar conditions and circumstances. For any higher level of mine planning it is clear that more exact data, including analytical and experimental analyses up to full-scale in-situ testing, are necessary. Basic gravity flow principles and design guidelines for the application of the sublevel caving mining method are presented in the following sections. Although some¬what simplified, they should provide a basis for mine planning and operation. The gravity flow principles described can be effectively applied to other mining situations, with some modification. Also, steep dipping coal seams can be effectively mined by modified sub¬level caving.

Jan 1, 1982

By Yu. A. Polozov, V. A. Lagunov, O. Yu. Lushinkova, Yu. I. Svirskiy, Eh. Ya. Kipko, Roy A. Williams

The STG integrated method of grouting can be divided into the several phases as outlined in preceding chapters. For convenience in describing technical procedures, they can be grouped as: 1. Investigations in non-geotechnical, exploration bore¬holes. 2. Drilling the holes necessary for geotechnical investiga¬tions and for grouting. 3. Conducting appropriate hydrogeologic tests in those holes and consequent calculations. 4. The preparation of a clay mortar. 5. The preparation of a clay-cement grout with additives. 6. The injection of the grout. 7. Checking the quality of the grout curtain. Items 2, 4, 5 and 6 are discussed below. These activities contain the procedural aspects of grouting. 7.1 DRILLING GROUT HOLES Grout holes belong to a very select class of drillholes. The necessary drilling equipment must enable the operator to drill the holes in inclined, twisting directions. In addi¬tion, the equipment must permit drilling under structurally and hydrogeologically complex conditions. The equipment must permit the operator to conduct specific testing activi¬ties in the drillholes. These activities include hydrodynamic analyses, flowmetric analysis, and the installation and re¬moval of deflectors, packers, grouting plugs, casings, lin¬ers, pumping facilities and other work. As explained in Chapters 5 and 6, the grouting of sat¬urated rock is conducted both through holes drilled from the surface and through holes drilled from the face of a shaft, drift, or tunnel. The drilling of grout holes from the surface can be carried out by an aggregate of equipment that can be the same equipment used for drilling exploration boreholes. Depending on the projected depth of the holes, the STG ZIF- 1200MR and ZIF-650 drilling rigs (or modifications of them) are used. The SKB-4, SKB-5 and SKB-7 high-output drilling rigs (workover rigs) have been used in recent years. The STG BMP-24 drilling rigs are used for carrying out the descent-lifting operations for drilling holes from the sur¬face. In a number of cases, the UKB-500C, URB-3AM and URB-2A power-fed drilling equipment is used for drilling holes from the surface. It should be noted that the drilling of grout holes usually requires an electric drive assembly. Drilling with diesel drive assemblies would be used only to preclude the possi¬bility of losing electric power during drilling operations. Turbine drilling would be used only for appropriate techni¬cal-economic reasons. The selection of the grout hole design is determined by the hydrogeological and structural geological conditions at the site as interpreted in Chapters 2 and 3. The design of grout holes must be as simple as possible in order to min¬imize costs. Hole design guidelines can be adopted as a basis for this purpose, unless site-specific conditions require otherwise. The mouth of the drillhole must be outfitted with a guide-pipe having a length of at least 2 m and an outside diameter from 219 to 234 mm. The upper part of the hole must be attached by a jig consisting of borehole casing that has a diameter ranging from 108 to 146 mm. The length of the jig h is determined by the equation [ ] where k = 1.1 to 1.2 is the load factor; P,, is the injection pressure of the grout into the mouth of the drillhole; D is the external diameter of the jig pipe; m = 0.6 to 0.7 is the work condition factor; T[ ].1 MPa is the bonding value of the rock cemented to the jig. The grout hole is drilled from the jig shoe to the de¬signed depth using a rock-crushing bit with a diameter of 93 mm or more. However in complex hydrogeological condi¬tions when the shaft intersects unstable rock, other hole designs can be used. The diameter of grout holes must permit an aggregate of investigations to be conducted in them using down-hole borehole geophysical and flowmetric logging instruments. It is necessary to cement the casing strings reliably in the grout holes, thereby permitting the injection of the grout under high pressure through the pres¬sure tight mouth of the borehole. Technological details for drilling grout holes such as the rotational rate of the drill bit, the axial load on the rock¬crushing bit, and the drilling fluid flow rate are optimized for the specific rock-hydrogeological conditions largely by experience. The hole diameter and type of rock crushing bit are important variables in these details of drilling. It is advisable to drill holes using water as the drilling fluid. However in those cases where the hole walls are unstable or under very high ground water pressure, the use of a well¬ engineered drilling mud should not be precluded. Unfortu¬nately, drilling mud can influence test results. When steeply dipping fractures with inclination angles of more than 60 to 70° are encountered, it is necessary to drill guided, inclined grout holes. This procedure permits the maximum number of fractures in each hole to be stu-

Jan 1, 1993

By Ian Farmer, Nigel Glossop, Philip Garritty

Performance of tunnel boring machines - usually expressed in terms of penetration per revolution - is determined by relations between machine thrust and torque, head diameter and rock strength. It can be shown that for a given machine power and head diameter there is only one rock strength at which the machine performs optimally. In weaker rocks the available torque limits performance and in stronger rocks, the available thrust. Performance data shows that, historically, machines have been designed to cut weaker rocks. Optimization of thrust is required to improve performance in stronger rocks.

Jan 1, 1987

By E. Stone, R. Reagan

Risk of hand injury is very real for operators carrying out conventional bolting operations with power torque tools, reaction arms and backup wrenches. Bolting operations of this type are common today in the installation and maintenance of heavy mining machinery and equipment. Newer solutions have become available that have the potential to dramatically reduce the risk of hand injuries in mining applications. MINING APPLICATIONS Within the scope of mining operations, various types of equipment are used such as tunnel boring machines, bucket wheel excavators, draglines, material handlers, screens, pumps, crushers, continuous miners and longwall systems. Design of these machines typically includes larger diameter bolts for strength and durability. Due to rugged use all machines require frequent maintenance and service which requires the use of heavy industrial bolting tools and methods. Those engaged in bolting operations include technicians working for end-users, equipment manufacturers, general contractors and others who provide services in mining operations. Most all personnel involved with these activities are engaged with use of high power bolting tools and procedures. Training is essential to raise the awareness of bolting safety and to avoid accidents. However improved bolting tools and procedures can play an even more significant role in further improving the safety of all those engaged with bolting in the mining industry. SAFETY CONCERNS Professionals working in the mining industry are constantly looking for ways to further reduce risk to health and safety. Bolting operations which are fundamental to service and maintenance of mining equipment are often overlooked as a potential area for improvement. Several areas of bolting operations offer potential for improvement in safety and avoiding accidents during equipment maintenance. This paper addresses the safety concerns associated with reaction arms and backup wrenches in conventional bolting applications (Figure 1).

Jan 1, 2019

By J. R. Hunter

The present is rooted in the past. This is particularly true in the case of mining operations. Coal mining in the United Kingdom is considered an old Industry comprising today 246 Coal Mines many of which have worked coal reserves in their locality for over 100 years. More than half the current producing mines lie in the Yorkshire and Midlands coalfields. They are in the oldest age group and produce 70% of the Industry's output. Some 50% of the remaining U.K. workable reserves amounting to approximately 98,000 million tons are still available to these regions. Fig. 1 Over the past two decades a gradual erosion of demand for coal in the U.K. has virtually halved the Industry's capacity. The number of Mines has reduced by 53% during the past 10 years. Productivity has increased by some 42% mainly through improvements in the central coalfields which has enabled costs to remain broadly competitive with oil.

Jan 1, 1976

By William B. Schmidt

In July of 1974 a study team comprised of the authors was formed by the Department of the Interior. It was supported in part by funding from the National Science Foundation. The purpose of this study group was to visit coal mines and research and manufacturing facilities in England and Germany, to review the status of mining in these countries, and to identify mining technology which might have application to U. S. mining conditions. The duration of the visit was 18 days. The first week of the trip was spent in England. Time does not permit a complete recitation of the team's impressions but a few of the more interesting technologic developments will be discussed. These fall into the following categories- High Speed Development Ground Support Chainless Haulage and Face Conveyors Nucleonic Steering of Shearers Miscellaneous

Jan 1, 1975

By Claude Boisjoly, Pierre de Courval, Don Nguyen

The Sainte-Marguerite-3 (SM3) hydro project, presently under construction, requires the excavation of an underground powerhouse and large water conveyance tunnels. This paper describes the planning of the project, main features of underground structures, excavation techniques and ground support.

Jan 1, 1997

By T. P. Smirnoff, R. J. Redmond, K .. N. Murthy

To minimize disruption to the Hollywood District of Los Angeles, a mined station using the New Austrian Tunneling Method (NATM) was developed. This paper presents the key factors contributing to the settlements and dynamic behavior of the unique binocular station design.

Jan 1, 1993

By Joachim Klein, Frank Reimann

Nodular-graphite cast iron (GGG) is a material similar to steel, and one which exhibits excellent properties, in particular for components exposed to pressure. GGG cast iron has been used in many cases when sinking mine shafts with conventional tubbing. With linings made of cast iron tubbings (the backfill concrete is not integrated into the calculations, and merely serves as bedding) the properties of the cast iron can be made full use of, provided the tubbing is made to the appropriate cross-section. Calculations have shown that better static values can be arrived at when using cross-sections other than those of tubbings made to conventional German standard. The cross-sectional design of the new types of shaft lining made from GGG is to be developed on these lines irrespective of the cast iron structure being only stressed component or its restistance function being combined with the one of concrete. GGG 50 is used for the first time to make the reinforcing inner liner of a main shaft currently sunk in Germany. The physical properties of nodular-graphite cast iron, strength and deformability, suggest that, in the future, its application will not be restricted to shaft support but also in tunneling. New moulding techniques with better three-dimensional modelling resulted in new tubbing designs as installed e.g. for the Hannover underground at present. Shield-driven tunnels have to withstand earth and water pressure, apart from axial machine loads. In this field time is money as well. Therefore easy handling and quick installation are necessary for successful, use. Last but not least, safety is of first-order importance for work in shaft sinking and tunneling. Cast iron lining systems, accordingly, are adequate systems, in particular for excavations underneath water for transport systems and for goods and passengers.

Jan 1, 1987

"The National Mining Hall of Fame and Museum (NMHFM) announced the class of 2019 National Mining Hall of Fame inductees. This year’s inductees, selected by the National Mining Hall of Fame’s Board of Governors, represent exceptional financial acumen in assembling several operations that formed the basis of a successful American mining company; conception and development of equipment which contributed to improved efficiency and mine safety; and unrelenting advocacy for the U.S. mining industry and its workers. These individuals, selected for being determined, forward-thinking innovators, doers and leaders have propelled the industry toward vastly improved safety and social responsibility.The Prazen Living Legend of Mining Award, named for renowned mining artist Gary Prazen, will also be presented at the ceremony. This award recognizes an individual or organization for significant and sustained commitment to educating the public about the relationship of mining to our everyday lives through educational materials, programming, and outreach.2019 National Mining Hall of Fame inducteesFrank Calandra, Jr. has devoted more than 50 years to the mining industry and he is an icon in ground control technology for the mining, tunneling and civil construction industries.From the ground up, his passion, sweat equity and shrewd business acumen have grown Frank Calandra, Inc. (FCI) and Jennmar from a single plant in Pennsylvania to a world-class enterprise with 25 plants employing thousands globally. As evidenced by Calandra’s more than 20 patents on ground control devices (not to mention the additional 80 patents his companies hold), his innovation and commitment to safety have made underground mining safer and more efficient. In the late 1970s and early 1980s, Calandra was instrumental in upgrading American Society for Testing and Materials (ASTM) standards in roof control for both state and federal regulations. Through his work with industry associations such as the National Mining Association, National Coal Council and Center for Energy and Economic Development, among others, Calandra has contributed his time, expertise and financial support to ensure a balanced political and regulatory climate for mining. Calandra is an inductee of the West Virginia Coal Hall of Fame."

Aug 1, 2019

By Jr. McCulloch

Mining operations of Freeport Indonesia (FI) are located approximately 4 degrees -6' south latitude, 137 -7' east longitude in Irian Jaya the eastern most state of Indonesia (Figure I). The mines are located approximately 96 km (60 miles) from coast in the Carstenz Mountain range. The ore bodies are between 2900 and 4000 meters (9500 and 13 000 ft) elevation.

Jan 1, 1989

By W Frint

An area in Southwestern Wyoming is rapidly becoming the soda ash capitol of the world. Starting only 20 years ago from a unique deposit of trona, the out-put has rapidly increased until now about half of the soda ash produced in the United States comes from this area. Chemically, soda ash is sodium carbonate, a large tonnage, widely used alkali. The largest single industrial use is in glass manufacture, where 25 tons of soda ash are used in producing 100 tons of glass. Other big users are the detergent and chemical industries. The trona deposits in the Green River basin of Wyoming, were formed about 75 million years ago as part of a geologic period when an ancient lake alternately went through periods of being a large fresh water or smaller brine lake. Today these deposits lie from 800 to 3000 feet below the surface in a semi-arid, almost desert region just west of the Rocky Mountain Continental Divide at an elevation of 6200 feet. In this area there is a prevailing westerly breeze and almost every afternoon the velocity reaches very windy conditions. Rainfall is minimal, being only 6-8 inches of moisture per year with an evaporation rate exceeding 24-inches. Most of the moisture comes in winter snows or summer thunderstorms. Temperatures are low with below zero weather dur¬ing most of the winter and early morning frost is not uncommon during the summer months. There are many trona beds varying in thickness from a few inches up to 15 feet. The deposits now being mined vary from 8 to 10 feet in thickness. The ore is mined by driving tunnels either via conventional explosives or with continuous boring machines. It is transported to the shafts via conveyor belts

Jan 1, 1972

By N. I. Jayaraman

Dust scrubbers on continuous miners are steadily gaining in popularity. Recent Bureau of Mines research on scrubbers is reviewed, with emphasis on the following areas: * Development of a new type of water-powered scrubber which can be retrofitted to existing miners. * Comparison of scrubber effectiveness with blowing and exhaust line ventilation. * Improving the quartz dust collection of flooded-bed' panels.

Jan 1, 1989

In 1936 a young Dutch geologist discovered an exposed ore mountain in the remote, mountainous province of Irian Jaya, Indonesia. This was the beginning of one of the most overwhelming challenges ever faced in obtaining mineral resources from the earth. The challenge was to traverse mangrove swamps and reach deep into the almost impenetrable jungles of the Jayawijaya Mountains which have an elevation of 4900 meters (16,000 ft.). The target was an almost inaccessible mountain of copper ore.

Jan 1, 1988