Search Documents

By G. E. Kedzie

The ore-deposits of ail that portion of the San Juan country within the borders of Ouray County are either in the tertiary ernptives or, confined to a relatively narrow zone, in the sedimentary beds just beneath them. The ore-deposits in the igneous formation

Jan 1, 1888

By Jack Parker

The White Pine mine site lies five miles south of Lake Superior in Ontonagon County, Mich. Copper sulfide, mixed with some native copper, is mined by a room-and-pillar system from gently dipping Upper Kewee-nawan sediments. Depth of mining now varies from 700 to 1800 ft and the ore body continues to a depth of at least 3400 ft. An area roughly 21/2 miles square has already been mined. Mining height has varied from 61/2 to 22 ft. A rock mechanics program was set up in late 1963 to promote safety and mining efficiency. This note reports some of the findings. Rock Strength Compressive strength of small, dry specimens of sandstones, siltstones, and shales from the ore zone varies from 20,000 to 30,000 psi. This is intermediate between the softer coal mine sediments and the meta-morphic and igneous rocks of hard rock mines. Annual Cycle of Rock Failure Since 1963, every roof and pillar failure involving more than a few tons of rock has been examined and documented. Some 1500 stations have been installed for measuring convergence, -c1/1000 in., with Invar extensometers. At first it was thought that there was some kind of a cycle of roof failures; perhaps annual, perhaps even elated to the moon or to earth tides, but records (see

Jan 1, 1971

By J.B. Pullen

The United Verde mine is in the north central part of Arizona, on the northeasterly slope of the Black Hills, near the town of Jerome. Ore was first discovered in the district about 1875, and the first mining claims were located by M. A. Ruff-ner and associates in 1877. In 1888 the late Scnator William A. Clark secured control of the property and under his ownership it developed into one of the country's most important copper producers. The property was sold to the Phelps Dodge Corporation in 1935, and since then has been under this Corporation's management. Except for shutdowns caused by general world-market conditions, production has been continuous from 1890 to date. Geology The mineralized zone ranges in area from approximately 12 acres to less than 5 acres. All mineralization occurs in the pre--Cam-brian intrusives. The first intrusion, according to geologic records, was the quartz porphyry, which later was intruded by augite diorite. Following the diorite intrusion through a series of intrusions of lesser magnitude, a pipelike mass of massive sulphide, quartz and rock was formed. The diorite forms the hanging wall of this mass, and the porphyry the footwall. Between the footwall and the sulphide a band of chlorite schist was formed, probably owing to metamorphic conditions. Commercial ore occurs along the contact of the schist and sulphide extending into the sulphide, sometimes entirely through the schist, and fingering out into the porphyry. The ore deposit was formed by replacement similar to deposits formed in limestone areas. Faulting and deformation occurred in pre-Cambrian times and again in the Tertiary period, removing approximately 2000 ft. from the top of the main United Verde ore body, forming the United Verde Extension ore body, the only other major ore body in the district. Major development work has shown that the sulphide mass extends to the 3300-it. level, and diamond drilling below this level has indicated that the mass might extend below the 3700-ft. level, but in a diminished quantity. While many copper minerals exist in the mine, the chief commercial mineral is chalcopyrite. Aplan and vertical section of the mineralized zone showing the principal geological eatures is shown in Figs. I and 2. General Description and Physical Condition or Mine After over 50 years of active production, ore still exists on almost every level of the mine. This condition is due to many causes —-mine fires, which broke out as early as 1894, caused the abandonment of certain areas; subsidence and ground movements retarded the cleaning up of others. Furthermore, in the early days there was such an abundance of ore that when mining became dificult it was a simple matter to replace the production by going to a deeper level. Several attempts were made to recover the ore in the fire zone, both by glory-holing

Jan 1, 1943

By J. B. Pullen

The United Verde mine is in the north central part of Arizona, on the northeasterly slope of the Black Hills, near the town of Jerome. Ore was first discovered in the district about 1875, and the first mining claims were located by M. A. Ruff-ner and associates in 1877. In 1888 the late Scnator William A. Clark secured control of the property and under his ownership it developed into one of the country's most important copper producers. The property was sold to the Phelps Dodge Corporation in 1935, and since then has been under this Corporation's management. Except for shutdowns caused by general world-market conditions, production has been continuous from 1890 to date. Geology The mineralized zone ranges in area from approximately 12 acres to less than 5 acres. All mineralization occurs in the pre--Cam-brian intrusives. The first intrusion, according to geologic records, was the quartz porphyry, which later was intruded by augite diorite. Following the diorite intrusion through a series of intrusions of lesser magnitude, a pipelike mass of massive sulphide, quartz and rock was formed. The diorite forms the hanging wall of this mass, and the porphyry the footwall. Between the footwall and the sulphide a band of chlorite schist was formed, probably owing to metamorphic conditions. Commercial ore occurs along the contact of the schist and sulphide extending into the sulphide, sometimes entirely through the schist, and fingering out into the porphyry. The ore deposit was formed by replacement similar to deposits formed in limestone areas. Faulting and deformation occurred in pre-Cambrian times and again in the Tertiary period, removing approximately 2000 ft. from the top of the main United Verde ore body, forming the United Verde Extension ore body, the only other major ore body in the district. Major development work has shown that the sulphide mass extends to the 3300-it. level, and diamond drilling below this level has indicated that the mass might extend below the 3700-ft. level, but in a diminished quantity. While many copper minerals exist in the mine, the chief commercial mineral is chalcopyrite. Aplan and vertical section of the mineralized zone showing the principal geological eatures is shown in Figs. I and 2. General Description and Physical Condition or Mine After over 50 years of active production, ore still exists on almost every level of the mine. This condition is due to many causes —-mine fires, which broke out as early as 1894, caused the abandonment of certain areas; subsidence and ground movements retarded the cleaning up of others. Furthermore, in the early days there was such an abundance of ore that when mining became dificult it was a simple matter to replace the production by going to a deeper level. Several attempts were made to recover the ore in the fire zone, both by glory-holing

Jan 1, 1943

Jan 1, 1940

Jan 1, 1940

Jan 1, 1966

By J. B. Clark, F. N. Rhines

THE A1-Mg phase diagram in the composition range from 30 to 60 pct Mg remains uncertain. Four intermetallic compounds are reported in this composition range. All of the published diagrams are in agreement as to the existence of intermediate phases near 37 and 52 pct Mg (Mgl,A1,). Confusion exists, however, as to the number and identity of the intermetallic phases present in the intervening composition range from 37 to 52 pct Mg. Mikheeva and Kurnakovl denote the existence of a phase e near 42 pct Mg. Kawakami," Reiderer? and Laves report a phase near 48 pct Mg. Eickhoff and Vosskuhler, from a critical survey of the literature, composed the diagram shown in Fig. 1, with the exception of the eutectoid horizontal of the e-phase shown at 210°C. RaynorV n a similar survey discounts the existence of the phase proposed by Ka-wakami et al.' at 48 pct Mg and reports a composite diagram similar to that of Eickhoff and Vosskuhler." This uncertainty as to the number of intermetallic phases in the A1-Mg system may be eliminated by annealing a diffusion couple of pure aluminum and

Jan 1, 1958

[ ]

Jan 1, 1938

By Fernando A. Buttazzoni, Jorge C. Munita

INTRODUCTION To provide a background for discussing long-range financial and operational planning in the mining industry, we would like to begin by describing the role of planning in Codelco. Having taken part in Codelco's planning process since its inception in 1976, we believe that useful conclusions may be drawn for the experience we shall relate. Although Codelco is a state-owned copper producer with an important role in the Chilean economy, and is consequently very much at the core of national economic planning, the following discussion is not related to government planning but to planning in an operationally and commercially autonomous business concern with all the characteristics of a private enterprise. The only way in which Codelco differs from private business is that its financial successes or failures have a more direct impact on the countryls ability to participate in international trade, to meet its international financial commitments and to achieve economic and social growth. Thus, what follows is a presentation of the conceptual features of the planning process at Codelco and a description of the current state of planning in the company. It is understood that certain conceptual components are basic to any formal strategic planning process, and that the components of Codelco's planning process are therefore generally applicable in similar companies. First, the mission and scope of operation of the company must be defined, and goals must be set to achieve leadership in the business activities in which it engages. Having set this framework, the company must constantly scrutinize those internal elements and conditions that are essential to fulfill its mission and achieve leadership. In Codelco this means considering the actions which can best serve to define future capacities, taking into account declining ore grades and determining optimal production levels; watching over the productivity and skills of its labor force, and; keeping abreast of technological developments in non-ferrous mining and processing. If the company is proficient in these three areas, it will be cost efficient and there- fore competitive. Codelco must also watch over the business environment in which it operates. The company sells concentrate, blister and fire-refined copper, wirebar, cathodes and wire rod and must study the behavior of the market to attune its product mix to the demand existing for these various commodities in the international market and the copper consuming industries in general. By examining the internal and external environment in which the company conducts its production and commercial operations, it is able to diagnose its strengths and weaknesses, to identify the hazards it must overcome to stay ahead in the copper trade, and to take full advantage of business opportunities as they arise. CHARACTERISTICS OF CODELCO-CHILE Although our subject is Codelco, readers should keep in mind that there are many other copper producing operations in Chile, all in the private sector, and many valuable deposits that may be exploited in the future. Codelco is the only public sector copper producer, although there is one other state enterprise that operates smelting and refining facilities principally to serve a large number of very small producers of copper concentrate. In the mid-19801s, Codelco is the largest copper mining company of the world and the largest producer and exporter of copper with yearly sales totalling close to US$ 1.8 billion in 1983. Moreover, it is a highly profitable copper company at a time when the world copper industry as a whole has reported losses for several years. Codelco-Chile is a fairly new organization. The history of the four mining operations it manages is much longer: El Teniente was opened in 1912, Chuquicamata in 1915, Salavador in 1959 -- with installations of the old Potrerillos mine dating from 1927 -- and Andina in 1970. Having had separate owners, the management systems of the

Jan 1, 1985

By A. S. McLatchie, R. A. Hemstock, J. W. Young

Much attention has been given in the past few years to methods of increasing the recovery of oil from proven reserves. Numerous laboratories have made investigations to evaluate the possibilities of increased oil recovery by high-pressure injection of dry gas, injection of a propane slug followed by dry gas, solvent flooding. and by the injection at relatively low pressures of gases enriched with ethane and propane. Several years ago, Whorton and Kie-schnick' published the results of laboratory studies on high-pressure gas injection which showed that, in the case of light oils, recoveries could be considerably increased by sweeping the reservoir with dry gas at pressures in excess of 3,000 psig. The increase was attributed by those authors to the vaporization of oil at the invading gas front and viscosity and solubility effects produced at the front by the invading gas. Later, Stone and Crump' presented the results of a series of displacement experiments in which a light under-saturated crude oil was displaced from sand-packed columns with unusually high recoveries when the displacing gas was a rich condensate or a dry gas enriched with ethane or propane. They also conducted similar experiments at higher pressure on heavy undersa tu rated crude oil, although in this case the increase in recovery was not as great as in the case of the light oils. In both cases, viscosity reduction and swelling of the by-passed oil behind the invading gas front were believed to be responsible for the more favorable recovery of the original oil in place. Within the past year, other investigators", ' have presented the results of laboratory studies of miscible slug and solvent flooding recovery processes. This paper describes the laboratory methods developed for evaluating benefits to be obtained by enriched gas drive in specific reservoirs, and presents the results of several displacements of crude oils which possess a wide range of physical properties. The displacements were conducted at reservoir conditions of temperature and pressure. The apparatus used in the following experiments consisted of a sand-packed tube which served as the model reservoir, a cylinder of injection fluid, and a mercury pump. The stainless steel tube, 8 ft long and 0.53 in. I- was packed with a graded quartz sand. The high-pressure pump discharged mercury into the bottom of the injection fluid cylinder at a constant rate as low as 1 cc/hr. The average porosity and permeability of the sand column were 34.6 per cent and 3.25 darcies, respectively. In each case the tube was charged by the displacement of salt water by the reservoir oil under consideration. Recently a project was initiated to evaluate oil recovery by enriched gas drive from three oil reservoirs. Samples from a fourth reservoir (in this case high-viscosity oil) were studied with a view to obtaining recovery information of general applicability to low-grade, high-viscosity crudes. The oils from these four reservoirs exhibited a wide range of physical properties, and the reservoir conditions of pressure and temperature simulated in the laboratory represented several typical field conditions under which enriched gas drive might be employed. One of the reservoirs selected for laboratory displacement experiments produced an intermediate-gravity crude (29.6" API) by solution gas drive and a weak water drive. A low recovery in the range of 10 to 20 per cent was anticipated. Four displacement experiments were made to determine the effect of injection gas composition and initial gas saturation upon recovery of oil from the laboratory model. Two types of reservoir oil were used in these experiments. In the first run, a desaturated crude with a bubble point of 395 psi was charged to the tube. In the three subsequent runs, a simulated original reservoir oil was charged at 2,000 psi and produced by solution gas drive to 300 psi before beginning gas injec-

By A. Lubinski, J. E. Hansford

Rotating drill pipe passing through dog-legs suffers fatigue damage due to cyclic bending stresses. Curves of the cumulative fatigue damage incurred in either steel or aluminum drill pipe going through Such dog-legs are presented. These curves provide means for properly planning the rate of angle build-up in directionally drilled wells and allow discarding of drill pipe which has been fatigue-damaged in dog-legs. INTRODUCTION Drill pipe which is subjected to bending as it rotates, experiences a cyclically varying bending stress. If this bending stress is sufficiently large, the drill pipe is fatigue-damaged by each revolution, and ages as fatigue damage accumulates. Drill pipe can be bent intentionally, as in the case of directionally drilled holes, or unintentionally due to unde-sired changes in hole direction caused by variations in formation properties, weight on bit, etc. These changes in hole direction, whether intentional or unintentional, are called dog-legs. The theoretical limits of dog-legs which are permissible before the drill pipe begins to fatigue can be calculated.' However, in wells where the maximum permissible dogleg is exceeded, the concept of cumulative fatigue damage can be used to estimate damage suffered by the drill pipe. This concept has already been used to estimate the cumulative fatigue damage of drill pipe due to drilling vessel roll.' The purpose of this paper is to extend the usage of the cumulative fatigue damage concept to drill pipe in doglegs, and to draw conclusions which may be beneficial in preventing numerous frustrating and expensive drill pipe failures. FATIGUE OF STEEL DRILL PIPE IN IDEALIZED GRADUAL AND LONG DOG-LEGS It is taken for granted that, if necessary, the reader will become familiar with the definitions and concepts which follow by examining the reference cited in each case. For Ref. 1, it will suffce to read only through the section Abrupt Dog-Legs. 1. Concept of the two extreme kinds of idealized doglegs: gradual and long dog-legs and abrupt dog-legs,' 2. Concept of why the bending moment in drill pipe un- der tension is the largest in the vicinity of the tool joint,' 3. Concept of why dog-leg severity which drill pipe can withstand decreases with an increase in tension,' and 4. Definition of the rate of change of over-all hole angle (dog-leg severity)." Figs. 1 and 2 indicate the aging (fraction of life expended) of steel drill pipe passing through a gradual and long dog-leg. Both figures have a left-hand ordinate scale labled Length of Drill Pipe Below Dog-Legs. This scale can be used for cases in which the drill collar weight is applied to the bit and does not contribute to the tension in the drill pipe. It can be used for either 3 1/2-, 4 1/2- or 5-in. drill pipe. This is due to the fact that, if the drill collars do not contribute to the drill pipe tension, then the effect of pipe tension on bending due to a change in pipe size is nearly compensated for by a corresponding change in pipe rigidity. On the other hand, if drill pipe is rotated off bottom, then drill collars contribute to the tension in the drill pipe and this increase in tension is not compensated for. In this case, one of the three right-hand ordinates must be used (the one which corresponds to the correct drill pipe size). In the right-hand ordinates, tension should be understood as the weight in mud of the portion of the drilling string below the dog-leg, minus the weight on bit.

Jan 1, 1967

Jan 1, 1967

By F. J. Darnell

SINGLE crystals of a-titanium are difficult to obtain because of the phase transformation at 882 °C in which the structure changes from the high-temperature body-centered structure ß to the low-temperature hexagonal close-packed structure a. Preparation of single crystals of a-titanium has previously been accomplished by a strain-anneal method which takes several days and is not generally reproducible. Single crystals as large as 5 mm

Jan 1, 1959

Jan 1, 1917

By B. H. G. Brady, C. M. St. John

Computational schemes for analysis of rock mass response to excavation, loading and other imposed changes, are employed pervasively in rock mechanics practice. Applications range in complexity from determination of stress and displacement distributions around openings, to prediction of the thermo-hydromechanical behaviour of a saturated fissured mass. While this may be taken as apparent sophistication in rock mechanics design activity, the indiscriminate use of computer methods may sometimes conceal inferior and inadequate engineering procedures. These inadequacies may not always be recognized, due to the general uncertainties which are inherent in rock mechanics investigations. This paper seeks to identify some common deficiencies in rock mechanics applications of computational schemes, and to propose ways of eliminating them. It also indicates some specific developments and applications of computational procedures, which are required to address persistent design problems in geomechanics practice.

Jan 1, 1982

By H. T. Byck

THE plastering properties of six representative California drilling muds were studied over a temperature range of 70° to 175° F. at several mud weights, using a high-pressure circulating filter press with full size consolidated cores. In all tests, with untreated as well as with chemically treated muds, the filtration rates at elevated temperature were higher than at low temperatures and in nearly every case this increased filtration rate was notably larger than could be attributed alone to the decreased viscosity of water-the flowing medium-at elevated temperatures. It is concluded that no existing method will permit even an approxi-mate determination of the filtration rate at high temperature from data at room temperature. It is necessary to measure filtration at the tem-perature actually anticipated in the well, or to make a sufficient number of tests at various lower temperatures so that a small extrapolation of these data to the anticipated well temperature may be applied. Such tests should be carried out on the mud as actually used in the well. The viscosity of each of the muds was determined over the same temperature range. While no relationship was observed between mud viscosity and plastering properties, it was found that chemical treatment of the muds for viscosity reduction shifted the temperature of minimum viscosity to appreciably higher values than for untreated muds.

Jan 1, 1939

The Howe Memorial Lecture, in memory of Henry Marion Howe, Past President of the Institute, was authorized in April, 1923, as an annual address to be delivered by invitation under the auspices of the Institute by an individual of recognized and outstanding attainment in the science and practice of iron and steel metallurgy or metallography, chosen by the Board of Directors

Jan 1, 1943

By L. C. Brown, E. B. Hawbolt

If a single-phase alloy is rapidly cooled such that insufficient time is available for an equilibrium transformation to occur, the high-temperature phase may be retained to room temperature or may undergo a massive or martensitic reaction. The massive or martensitic product develops without a composition change and usually has a crystal structure approximating an adjacent equilibrium phase. The characteristics of a massive transformation are intermediate between the equilibrium reaction in which long-

Jan 1, 1969

By J. J. Sense

10.2-1. Equipment Scheduling. In any earth-moving operation, more profit may be earned or lost by equipment scheduling than by any other single facet of the project. Many now-defunct earth movers would have survived the cost-profit squeeze had they followed an efficient, cost saving, equipment scheduling program. The ideal program would have every item of the equipment fleet working all of the time. In practice for many obvious reasons, principally mechanical conditions, operating conditions, and human nature-this ideal situation is not possible. The cost-conscious organization strives to keep as many pieces of equipment of the fleet working efficiently as much of the work day as possible. Operating efficiency requires the minimum equipment to move the predetermined tonnages in the prescribed period of time. In the case of a shovel-truck operation this would mean the scheduling of the minimum shovel and truck shifts to excavate and transport the necessary tonnage to the processing plant or waste dump. To accomplish this goal, the operator must work from the predetermined production established by the requirements of the plant, stripping ratio, mine plan, etc. This production schedule may be in terms of tons or yards per year, per month, or per hour, but must eventually be translated into tons or yards per ma- chine per unit of time. In this regard, the reader is referred to Sections 8.0, Excavation and Loading, and 9.0, Haulage and Transportation. The trend to larger and faster, and as a result more costly, equipment requires that the operator consider every possibility to keep the equipment operating around the clock, seven days per week. In some areas seven day operation may not be feasible economically, because of premium pay for Sunday work. Mine labor agreements are generally written without premium pay penalties for weekend work, and such scheduling is possible and most often desirable.

Jan 1, 1968