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By E. R. Borcherdt

METHODS and equipment are subject to study in the Butte district at all times in order that advantage may be taken of any new developments that might serve to increase efficiency and lower costs. Detailed time studies of each operation involved in the entire mining process have been of invaluable assistance in analyzing the individual operation for possible improvement. In other words, the fact that a practice has been in vogue for many years does not exempt it from change provided an easier and cheaper method can be found. EXPLORATION Ore occurs in the Butte district in such manner that structures must be drifted on, no matter how small or unimportant they appear when intersected by a crosscut. Parallel structures also add to the crosscut requirements. This prospecting work, which formerly was done entirely by drifting and crosscutting, is now being supplemented by diamond drilling, to aid in greatly decreasing the amount of waste. In long-shot prospecting, or in second or third class prospecting, where the chances of developing commercial ore are not very great, diamond drilling is of particular value. In prospecting where chances of encountering commercial ore are certain or where crosscuts can be used later for haulage or ventilation, drilling obviously is not applicable. Improvement in drilling machines and bits has contributed greatly to the present success of diamond drilling. STOPING For many years square-set filled stoping was the principal mining method used in the Butte district. Later timbered and untimbered rill stopes were used, also some horizontal cut-and-fill stoping where both ore and walls were particularly strong. Because of the amount of timber required for square-set stoping, and the relatively low production per stope unit, experiments with horizontal cut-and-fill stopes were begun in ore bodies of which many had fairly weak walls. It was felt that increase in the speed of the stoping operation, followed closely by filling, to avoid weight being produced by permitting ore and walls to remain insufficiently supported over comparatively long periods, would maintain the walls and backs in safe condition without the use of timber and without ore dilution from wall slough. Cycles of drilling, scraping ore, and filling were devised, which have materially increased stope production and decreased timber consumption, so that both stope labor and supply costs were lowered appreciably without materially affecting grade control. In the larger mines of the district, where wide veins favor this stoping method, half of the total production is now being mined by horizontal cut-and-fill stopes (Fig. I). The increase of the filling rate demanded by the increased stoping rate was the greatest obstacle encountered in the accelerated stoping operations. Finally this problem was solved by replacing the time-honored method of transferring filling waste by small cars, which were hoisted or lowered in the auxiliary shaft, by a transfer

Jan 1, 1941

By E. R. Borcherdt

METHODS and equipment are subject to study in the Butte district at all times in order that advantage may be taken of any new developments that might serve to increase efficiency and lower costs. Detailed time studies of each operation involved in the entire mining process have been of invaluable assistance in analyzing the individual operation for possible improvement. In other words, the fact that a practice has been in vogue for many years does not exempt it from change provided an easier and cheaper method can be found. EXPLORATION Ore occurs in the Butte district in such manner that structures must be drifted on, no matter how small or unimportant they appear when intersected by a crosscut. Parallel structures also add to the crosscut requirements. This prospecting work, which formerly was done entirely by drifting and crosscutting, is now being supplemented by diamond drilling, to aid in greatly decreasing the amount of waste. In long-shot prospecting, or in second or third class prospecting, where the chances of developing commercial ore are not very great, diamond drilling is of particular value. In prospecting where chances of encountering commercial ore are certain or where crosscuts can be used later for haulage or ventilation, drilling obviously is not applicable. Improvement in drilling machines and bits has contributed greatly to the present success of diamond drilling. STOPING For many years square-set filled sloping was the principal mining method used in the Butte district. Later timbered and untimbered rill stopes were used, also some horizontal cut-and-fill sloping where both ore and walls were particularly strong. Because of the amount of timber required for square-set stoping, and the relatively low production per scope unit, experiments with horizontal cut-and-fill scopes were begun in ore bodies of which many had fairly weak walls. It was felt that increase in the speed of the stoping operation, followed closely by filling, to avoid weight being produced by permitting ore and walls to remain insufficiently supported over comparatively long periods, would maintain the walls and backs in safe condition without the use of timber and without ore dilution from wall slough. Cycles of drilling, scraping ore, and filling were devised, which have materially increased stope production and decreased timber consumption, so that both stope labor and supply costs were lowered appreciably without materially affecting grade control. In the larger mines of the district, where wide veins favor this stoping method, half of the total production is now being mined by horizontal cut-and-fill stopes (Fig. I). The increase of the filling rate demanded by the increased stoping rate was the greatest obstacle encountered in the accelerated stoping operations. Finally this problem was solved by replacing the time-honored method of transferring filling waste by small cars, which were hoisted or lowered in the auxiliary shaft, by a transfer

Jan 1, 1941

By Stanley J. LeFond, Langtry E. Lynd

Elemental titanium has become famous as a space age metal, because of its high strength/ weight ratio and resistance to corrosion. However, the major use is in the form of titanium dioxide pigment, which because of its whiteness, high refractive index, and resulting light-scattering ability, is unequaled for whitening paints, paper, rubber, plastics, and other materials. A relatively minor use is in welding rod coatings, in the form of the mineral rutile. United States consumption of titanium dioxide in concentrates for these applications in 1982 was as follows: pigments, 630,000 st; titanium metal, 31,000 st; and welding rod coatings, 5,000 st. The only commercially important titanium ore minerals at the present time are ilmenite and its alteration products, and rutile. Titanium was discovered by Gregor in 1790, as a white oxide which he recovered from menaccanite, a variety of ilmenite occurring as a black sand near Falmouth, Cornwall. Barksdale (1966) stated that the fundamental chemical reactions on which the present day titanium industry is based were known before 1800, although it was not until 1918 that these pigments were available commercially on the American market. Pings (1972) outlined the early history of the titanium industry in the United States, referring to the work of Guise (1964) and others: Mining of titanium minerals in the United States began sometime between 1880 and 1900, in Chester County, Pennsylvania. Small quantities of rutile were also produced during that time in North Carolina and Georgia. In 1901 rutile was mined from a deposit near Roseland, VA, and was used in making titanium chemicals and for coloring ceramics. Ilmenite in the deposit was produced as a separate item in 1913, and rutile and ilmenite were obtained from this deposit through 1921. The mining of titanium bearing beach sands began in 1916 near Mineral City and Pablo Beach, FL, for the purpose of making titanium tetrachloride to be used in tracer bullets, flares, and smokescreens. The titanium pigment industry was founded in 1918. By 1928 a large part of the domestic production of rutile, ilmenite, and zircon came from Florida. However production ceased in 1929 in Florida with the mining of newly discovered deposits in Virginia which were mined until 1968. The discovery of new deposits in Florida, and the development of better mining and concentrating methods for low-grade sands, led to a return of activities in this area. The large deposits near Tahawus, NY. were brought into production in 1942 by National Lead Co. (now NL Industries, Inc.), and by 1949 this company was the leading producer of ilmenite in the world. In 1948 the extensive deposits of ilmenite and ilmenite-bearing iron ores were discovered in eastern Quebec. The large Trail Ridge sand deposit in Florida was discovered by E. I. du Pont de Nemours & Co., Inc. geologists in cooperation with the US

Jan 1, 1983

By Henry J. Sandri

ACQUISITION JUSTIFICATION There are many reasons why companies consider acquisitions as a means to expand their operations. Some wish to reduce the impact of business cycles on their businesses. Others seek firms within the same industry for expansion and increased market share. Still others diversify in order to avoid takeovers. Whatever the reasons or justification, an evaluation of an acquisition candidate should be systematic and thorough. To many financial managers the concept of a systematic acquisition evaluation indicates the need for a regular set of evaluation criteria. While these are available from numerous sources, one basic parameter frequently overlooked is the application of these criteria to an industry which is different from the acquirer. This becomes particularly important when evaluating firms within the mineral industry. The mineral industry is significantly different from other industries to require different valuing techniques. • This paper will present a number of reasons why an acquisition candidate in the mineral industry should be evaluated differently from other acquisitions, including by other mineral firms. Additionally, this paper will review the most appropriate means of valuing a mineral firm. • Firms considering the acquisition of a mineral firm should understand the nature of the industry before ever making a tender offer. Some of the general considerations include the following: • Level of Capital Intensity: In the mid-1980's the start up cost for a gold mine has been between 20-200 million dollars and 500-1,500 million dollars for a bauxite operation. • Global Nature of Competition: Except for certain industrial minerals, most minerals and metals are traded worldwide and many on national exchanges, such as COMEX. • Start-Up Time: Many mining operations in developed and developing countries have long lead times, 7 to 10 years in some cases, prior to the start-up of production. • Long Term Nature of Investment: For most mineral operations payback usually occurs at least 7 years after production has started. Additionally, many mining operations will continue producing for 80-100 years. • High Level of Risk: The number of factors that a mining firm cannot control such as grade, volume, world supply and demand, plus the long payback periods tend to classify mineral firms at a higher than average risk compared to other investments. • Cyclical Nature: The mineral industry is cyclical in nature, experiencing long troughs and explosive peaks, thus making timing a critical issue. • Labor Intensive: Even with the large capital requirements needed to operate a mine, most mines are labor intensive in proportion to their capital equipment. • Location: Obviously, the nature of this industry requires operators to work in difficult locations, frequently far from civilized localities, in poor weather conditions and without proper supply and distribution infrastructure. One of the most important considerations is an understanding of asset replacement and asset value. Unlike manufacturing concerns, firms in the mineral industry are working toward the elimination, through depletion, of their asset base. Product flexibility is not available to a mining operation. A mineral firm basically has two options as its resource base is depleted: 1) replace the asset with new production, or 2) deplete the asset and close down operation, as in the South African gold mining model referred to later in this paper. An understanding of the

Jan 1, 1985

By W. A. Backofen, G. Mayer

Single crystals of iron, copper, and a Cu-7 wt pct A1 alloy were pulled through conical dies to simulate the constraint in a polycrystalline aggregate undergoing axisymmetric reduction. With Taylor-type hardening, dependence of the drawing stress, od, on the Taylor orientation factor, M, is predictable from the polycrystal stress-strain curve; in particular, for a power-law relationship, it should follow that d log od/d log M = (1 + n). A first-order agreement with analysis was found in the data from iron. For copper, the implied n from the observed d log od/d l°g M was -0, while for Cu-7Al it was negative. The trend was in the direction of random polycrystal behavior. Thus the idea of hardening only in response to the amount of prior slip loses validity as stacking fault energy (SFE) is lowered. Two possible explanations have been suggested: as stacking fault ribbons are widened, barriers from dislocation reactions become increasingly effective in dispersing slip and reducing the orientation dependence of the total glide strain dm that appears in alternatively, or conjointly, the polyslip shear stress, 7, acquires an orientation dependence of a kind which has the same leveling effect on M. The problem of relating the strain hardening of polycrystalline material to that of an isolated single crystal is still largely unsolved. In a new experimental approach from recent work, single crystals of different orientations have been deformed under the constraints found in an aggregate while measuring their deformation resistance. Procedures have involved drawing cylindrical crystals through conical dies1 and compressing slab-shaped crystals in plane strain.2'3 Predictions for the outcome of such experiments were made first by Taylor~ and later, in more general form, by Bishop and Hill.5'6 Taylor's example was the axisymmetric extension of an fcc crystal slipping on the usual {111}(110) systems or, equivalently, a bcc crystal undergoing 'kestricted" slip on {110}(111). In his solution, the deformation work supplied was equated to that dissipated internally in slip on all active systems. With o the single applied tensile stress, dc the resulting axial strain, and dyT the total glide strain on systems operating at resolved shear stress, 7: The orientation dependence of M was found by minimizing dyT for each orientation while activating five independent systems, Fig. l(a).? The Bishop and Hill analysis, based on a principle of maximum work, leads to essentially the same conclusion; the need for at least five active systems is recognized in the finding that either six or eight are actually brought into operation. The mean value from the entire stereo-graphic triangle in either case is M - 3.06. More recently, Hutchinson8 made a Taylor-type analysis for pencil glide in a bcc structure, from which piehlerg prepared Fig. l(b) as the counterpart in Fig. l(a); here M = 2.75. The obvious weakness in such analyses is the indifference to slip-system interactions. A condition of what might be termed "independent"

Jan 1, 1969

By J. F. Gallie

From the standpoint of exploration and new discoveries, South Arkansas had a discouraging year in 1944. In January there were 73 untested drilling blocks, and 60 additions were made during the year. Of the total, 65 were condemned by dry holes on or adjacent to them, while 5 proved productive. The latter resulted in the discovery of the Salem Church, Calhoun Wilks, and Strong fields, and the extension of the Village field to the southeast. The year ended with 63 untested blocks, 41 of which were scheduled for tests to the Smackover lime, the state's deepest oil-producing formation. Geophysical activity in 1944 totaled 164 crew weeks, of which 110 were seismic, 43 gravity, and 11 radioactive (Fig. I), in contrast with 674 crew weeks reported for 1943, of, which 563 were seismic and in gravity, Five seismograph and two gravity crews were engaged in exploration in South Arkansas during January 1944. but only two seismograph crews were working there at the end of the year. In addition, exploratory core drills were used for a total of 38 weeks during the year. The year's few discoveries, none of which is considered as having added appreciably to state reserves, were the meager results obtained in the drilling of 62 wildcat wells 2000 ft. or deeper. Of this total (a detail of which appears in Table 2), 42 were drilled to the Smack-over lime or below, The average depth of the 62 wells was 5384 ft., as compared with 4992 ft. in the preceding year, while the average depth of the 42 wildcats in the lime was 5913 ft. in 1944. Fig. 2 has been prepared to show all , wells penetrating to the Reynolds oölitic lime. The 1944 dry holes are circled lightly, while discoveries are heavily circled and shown as producers. Smackover lime fields, producing from the Reynolds oolitic lime member, are indicated in black, and the locations of dry wildcat wells drilled prior to 1944 are also shown. Table 3 provides a listing of all Smackover lime wells drilled through the end of 1944. Production for the year was slightly more than in 1943, totaling 29,282,747 bbl., as compared with 27,521,943 bbl. for the preceding year. The increase was 1,760,804 bbl., or 6.4 per cent, bringing production to a peak exceeded only in the 1923 to 1928 period of flush production from the older shallow fields, principally Smackover. The increase was largely attributable to additional development in the Dorcheat-Macedonia, Atlanta, Fouke, Stephens-Smart, Haynesville, and Village fields, little production deriving from 1944 discoveries. These six fields accounted for loo of the 122 field wells drilled during the year. Annual and cumulative production for the producing life of the state are presented graphically in Fig. 3. Fig. 6 has been prepared by the author to show the producing ages and present known productive limits of all fields in South Arkansas. Production data, as usual, are assembled in Table 2, and provide a further breakdown of producing formations in the individual fields.

Jan 1, 1945

By W. R. Foster, J. M. McMillen, A. S. Odeh

The complete equations of average linear momentum balance for a single-phase fluid in an incompreisible, homogeneous, porous medium are derived. The derivation begins with Euler's equation of motion for a continuum and uses an integral transform recently developed by Slattery. 7 For steady flow of a compressible, Newtonian fluid, the usual equations of motion result. For transient flow, the space-time description of the pressure is determined in the lowest approximation by the telegrapher's equation. From the analysis a new phenomenological coefficient results which connects the viscous traction to the deriv ative of the linear momentum density. The magnitude of this coefficient determines the velocity of sound through the pore structure in this approximation to the pressure field. INTRODUCTION The modification of Darcy's law of momentum balance for steady, single-phase flow through porous media has been discussed for many years. The first modification was suggested by Forcheimerl who added terms of higher order in the velocity. These can be expected to appear because the underlying microscopic equations of momentum balance are themselves nonlinear in the point velocity field. The Reynolds tensor pvv, which represents the convective flux of momentum density, appears in the momentum balance equation. Only in rectilinear flow (parallel stream lines) does the divergence of this tensor vanish. Since the steady flow stream lines in most porous media are not parallel, nonlinear dependence of the pressure gradient on the velocity should naturally appear. This nonlinearity has nothing to do with turbulence in the ordinary sense of random fluctuations in the pressure and velocity fields. It arises simply because the stream lines converge and diverge, even for steady flows. Klinkenberg2 demonstrated that the permeability coefficient in Darcy's law depends on the absolute pressure or, alternatively, on the density field. However, because he neglected inertial terms of the Forcheimer type, his correction coefficient could not be represented by a constant but tended toward a constant as the velocity decreased. Forcheimer's and Klinkenberg's modifications can be combined in a rigorous way to account for both inertia and slip during steady flow. This will be shown in a future paper. The transient change of pressure in porous media has been described by the diffusion equation.3 This form results from eliminating the velocity and density fields from a combination of the equations of motion in the form of Darcy's law, the continuity equation and an equation of state. Fatt4 suggested that the cause of deviations from the prediction of the diffusion equation for pressure transients lies not in the choice of Darcy's law as the equation of motion but on the existence of dead-end pores which might invalidate the averaged equation of continuity. On the other hand, Oroveanu and Pascal5 noted chat the time derivative of the momentum density must be included in the equations of motion since this measures the local rate of change of momentum density. Their differential equation for pressure is the telegrapher's equation (neglecting gravity). However, their form of this equation predicts that the speed of pressure propagation through the pore structure is the same as that through the bulk fluid. M. K. Hubbert6 attempted a derivation of Darcy's law by volume averaging the Navier-Stokes equations. Since these equations represent momentum balance at a point within an open set of points containing the fluid itself, Hubbert's volume averaging cannot lead to tenns involving transfer of momentum between the fluid and the walls of the pores. Once these viscous tractions are lost by choosing a control volume containing only fluid, they cannot

By R. T. Torgerson, W. A. Baginski

Alloying studies were conducted on modifications of Cb-10W-1OHf (C-129) alloy as part of a cooperative alloy development effort between The Boeing Co. and the Wah Chang Corp. The purpose of these studies was to develop a fabricable, high- strength columbium alloy with superior melding properties. The initial investigations of alloy modifications were conducted using laboratory-melted button ingots. An alloy with the composition exhibited excellent veld ductility, elevated-ternpevature strength, and fabricability. The yttrium-modified alloy was desigrzated C-129Y and was selected for further developrnetzt. Three prodziction heats of C-129Y weve processed into sheet. Welding, forming, and tensile proper-lies are presented for this material. Tungsten-are welds of. C-129Y exhibited a minimum bend radius of 1/2T in the as-welded conditioti compared to 8T for C-129 alloy. An investigation was conducted on Disil coating of C-129Y and test data are presented on oxidation resistance and effects of re-entry environments. The excellent combination of strength, fabricability, weldability, and low transition temperature of C-129Y alloy offers potential design advantages for use of this alloy in structures of aerospace vehicles. It is atiticipated that C-129Y will rapidly supplant C-129 and similar alloys clue to the versatility provided by its impvoved welditzg properties. COLUMBIUM alloys with improved properties are required to achieve better performance and efficiency of radiation-cooled structures for re-entry vehicles and recoverable launch systems. Cooperative work by The Boeing Co. and the Wah Chang Corp. resulted in the development several years ago of C-129 alloy, a high-strength Cb-W-Hf alloy.' This alloy has received favorable consideration for many advanced designs of high-temperature structures due to its excellent combination of properties. However, this alloy exhibits low weld ductility unless given a high-temperature stress-relief treatment. For this reason the development effort was directed towards modification of the C-129 alloy composition (Cb-1OW-1OHf) to eliminate the need for post-weld heat treatment. This paper describes the successful development of an alloy meeting this requirement. This new alloy was designated C-129Y and has a nominal composition of EXPERIMENTAL PROCEDURES Alloying Studies. Various Cb-W-Hf compositions were investigated using are-melted button ingots. These buttons were hot-forged using a protective glass coating and rolled into sheet specimens. Metal-lographic examination: tensile testing, and welding studies were conducted to evaluate properties of the experimental alloys. Sheet Fabrication. Three pilot production heats of C-129Y were fabricated into sheet to establish processing techniques and to determine sheet properties. The three heats consisted of 6-in.-diam ingots weighing from 140 to 250 lb. The ingots were prepared by electron-be am melting followed by vacuum-arc melting. The hafnium and yttrium additions were made during the are-melting operation by tack welding alloy strip additions to the Cb-W master-alloy electrode. The final ingots were machined into billets with samples of the machine turnings collected for chemical analysis. Ingot breakdown methods for the three heats are as follows: Ingot Ingot Heat Size Weiaht___Breakdown Method A 6 in. 250 lb Hot extrusion B 6 in. 140 lb Hot forging C 6 in. 250 lb Hot extrusion Sheet bars from the extrusion and forging operations were conditioned, recrystallized, and rolled into sheet. Initial rolling was conducted at elevated temperatures and final rolling was conducted at room temperature.

Jan 1, 1967

By AIME AIME

CHARLES A. CHASE, manager of the Shenandoah-Dives Syndicate, operating the Shenandoah Mines in southwestern Colorado, reviewed the current work at that property at a recent meeting of the Colorado Section, in Denver. This operation is a new one, having been in effect only two years, but the properties that were consolidated by Mr. Chase had had certain production in earlier years, since when they had: been inactive. These properties are located. in the high mountains of the San Juan section in Colorado, and although they had had a substantial production of ores of good grade in the upper levels, the project as a whole involved the bold undertaking of driving through the mountain, starting on the Mayflower claim on the Arrastre Gulch side and passing through the Mayflower, Slide, Terrible, North Star, Dives and Shenandoah No. 3 claims. This is a distance of over 8,000 ft. which is known to be mineralized, and the main operating tunnel was started at an elevation of approximately 11,000 ft. The main exploration work has already extended in nearly 4,200 ft. and the present mining production of nearly 550 tons daily is being secured while the main exploration work is being continued. The main heading is now within the North Star claim and the plan of operations involves continuing ahead for a few hundred feet and then starting an upraise which will he 2,200 ft. high and which will connect with the old workings of the North Star mine. The plan of ruining then will he to drive levels along the vein in both, directions to daylight and retreat downward, taking out all the ore and abandoning, the workings after the ore is removed. In this way one level after another progressing downward will be abandoned. The raise will be of two compartments, one of which will carry the 8-ton skip and the other the counterweight and manway. So far the ore has been broken over an average width of more than 11 ft., with an output of 39 tons per machine shift.

Jan 1, 1932

By W. F. Boericke

The character of the Wisconsin orebodies must be clearly understood to appreciate the difficulties encountered in sampling and estimating them. Unlike the western vein deposits, they do not lie between regular walls, but form large, often highly irregular bodies, on a single floor in the so-called Galena limestone. The bottom of the ore is nearly always on the clay bed (a flat generally well-defined clay seam a few inches thick) which marks the junction of the base of the Galena lime and the top of the next formation, the Trenton lime. Above the clay bed, the orebodies make the unique pitch and flat formation described by Chamberlin.' Theoretically, we should find two pitches, one on either side of the top crevice, diverging as they go down, with the final flats a considerable distance apart on the clay bed. The area between, known locally as core ground, should thus constitute a single defined orebody, with the richer portions near the pitches and the leaner portion in the center of the core. Practically, we find few examples of this perfect orebody. Almost invariably one pitch is better defined than the other, and often the opposite pitch is marked only by a faint line of fracture showing stronger mineralization than the wall rock, or it may be totally lacking. But with an orebody of any size or richness, at least one strong pitch usually tends to follow an east-west trend, or a quartering course. Late mining developments in the rich New Diggings field indicate that these pitches often assume a horseshoe or crescent shape, the richer ore being in the heart of the crescent and the pitches showing less mineralization as they extend outwards. In the northern end of the field, on the contrary, the pitches maintain generally a consistent direction, and have been mined for thousands of feet from the shaft. The length of the orebody may be several thousand feet, the height varying from 10 to 60 ft. and the width from 60 to 250 ft. In fact, on the core side, there is no definite end to the ore. The mineralization simply gets thinner and thinner, and the limit of working depends on the cost sheet and the profit from the recovery.

Jan 1, 1923

CONTENTS PAGE UREN, LESTER C.-Increasing Production of Petroleum by Increasing Diameter of Wells. Discussed by A. Beeby Thompson 1 LAHEE, FREDERIC H.-Comparative Study of Well Logs on the Mexia Type of Structure. Discussed by W. A. I. M. van Waterschoot van -der Gracht.... 4 Increasing Production of Petroleum by Increasing Diameter of Wells Discussion of the paper of LESTER C. UREN, presented at the New York Meeting, February, 1925, and issued, as Paper No. 1364-G, with MINING AND METAL-LURGY, October, 1924. A. BEEBY THOMPSON, London, Eng. (written discussion).-The subject discussed in this paper has long been debated by operators in European fields, where very strong views are held regarding the advisability of controlling gas pressures by shutting in wells. While unwilling to theorize on the subject of restricted flow, the writer has always been disposed to associate himself with those who hesitate to impose any obstruction to a natural transitory state that breaks up the oil-containing strata and establishes a feeder system which no subsequent events, natural or artificial, can approach in intensity. In both Russia and Roumania, where the oil is concentrated in discontinuous, disturbed, and irregular lenticles of sand varying, within short distances, in coarseness of grain, extent of impregnation and degree of cementation, it has been the practice to let the wells run wild in order to provoke disruption of strata. By encouraging violent eruptions, an extended feeder system is created and the ejection of enormous quantities of sand, rock, and clay creates a sump and seepage area that it would be difficult to imitate by any artificial means, not excluding actual mining. Before discussing the somewhat novel method suggested for enlarging the infiltration area, the writer would like to confirm the fact that many valuable data applicable to oil are forthcoming from a study of water phenomena. Long association with water-supply problems in many parts of the world has shown how closely the phenomena of underground movements of water and oil are related, so that it is pleasing to note the author's use of water formulas. But there is one great distinction;

Jan 7, 1925

By W. F. Boericke

The character of the Wisconsin orebodies must be clearly understood to appreciate the difficulties encountered in sampling and estimating them. Unlike the western vein deposits, they do not lie between regular walls, but form large, often highly irregular bodies, on a single floor in the so-called Galena limestone. The bottom of the ore is nearly always on the clay bed (a flat generally well-defined clay seam a few inches thick) which marks the junction of the base of the Galena lime and the top of the next formation, the Trenton lime. Above the clay bed, the orebodies make the unique pitch and flat formation described by Chamberlin.' Theoretically, we should find two pitches, one on either side of the top crevice, diverging as they go down, with the final flats a considerable distance apart on the clay bed. The area between, known locally as core ground, should thus constitute a single defined orebody, with the richer portions near the pitches and the leaner portion in the center of the core. Practically, we find few examples of this perfect orebody. Almost invariably one pitch is better defined than the other, and often the opposite pitch is marked only by a faint line of fracture showing stronger mineralization than the wall rock, or it may be totally lacking. But with an orebody of any size or richness, at least one strong pitch usually tends to follow an east-west trend, or a quartering course. Late mining developments in the rich New Diggings field indicate that these pitches often assume a horseshoe or crescent shape, the richer ore being in the heart of the crescent and the pitches showing less mineralization as they extend outwards. In the northern end of the field, on the contrary, the pitches maintain generally a consistent direction, and have been mined for thousands of feet from the shaft. The length of the orebody may be several thousand feet, the height varying from 10 to 60 ft. and the width from 60 to 250 ft. In fact, on the core side, there is no definite end to the ore. The mineralization simply gets thinner and thinner, and the limit of working depends on the cost sheet and the profit from the recovery.

Jan 1, 1923

By C. A. Mitke

The United Verde Extension mine is located in the Jerome mining district, on the eastern slope of the Black Hills, approximately northeast of the town of Jerome, Yavapai County, Arizona. The ore deposit may be termed a replacement in Yavapai schist. This schist is one of the oldest formations in the district, being probably of volcanic origin, and has been folded and faulted and contains intrusions of diorite and quartz porphyry. It is believed that the mineralization followed the porphyry intrusions and replaced the country rock; this was followed by erosion and a period of secondary enrichment, all completed in pre-Cambrian time. Later sediments of sandstones and limestones, to the depth of approximately 600 ft. (182 m.), were laid down, followed by volcanic flows. Faulting and erosion again took place, resulting in the present complicated arrangement of the strata. Prospecting, therefore, is very difficult, because the sediments practically cover the mineralized areas. This necessitates the sinking of deep shafts, cross-cutting, and, in some instances, diamond drilling to learn something of the various relations of the different formations and the occurrences of intrusions associated with ore deposition. The locating of new orebodies, therefore, is beset with innumerable difficulties. EARLY MINING METHODS The two orebodies constituting the principal resources of the company are known as the small orebody and the Bonanza, or large orebody. These are about 150 ft. (45 m.) apart, and while they appear to be distinct orebodies may later prove to be connected. The character of the ore, the general associations of the porphyries adjoining the orebodies, and other characteristics, both in the ore and general environment, are very similar. The small orebody was the fist to be discovered and was mined for some time before the Bonanza was found. At first, a large amount of ore was extracted by means of development work, but as the smelters treating this class of ore were located from 60 to 400 mi. (96 to 643 km.) away, only the highest grade yielded a fair profit and it became necessary to do selective mining. The main workings

Jan 1, 1920

By S. J. Kidder

Application of shrinkage stoping methods, without filling, in the mining of large silver-gold orebodies in the Mogollon district, where the ore is hard and wall rocks stand well without timbering and where veins make little water. Vertical and inclined shafts in use with both surface and underground hoisting stations. Storage pockets used on main hoisting levels, with electric signals and telephones for communication. Power is generated by De La Vergne engines having a total sea-level rating of 1540 hp. On account of the remote location of the camp, transportation is an important item of expense, amounting in 1922 to $0.641 per ton of ore milled or $0.265 per ton-mile on all freight hauled. THE Mogollon mining district is in the southwestern part of New Mexico near the southern end of the Mogollon range, from which the district takes its name. The town of Mogollon is but 37 1/2 mi. in an air line northeast of Clifton, Ariz. The air-line distance from Silver City is 52 1/2 mi. and from Tyrone, 57 mi. Supplies are transported by motor truck from Silver City. The distance by road is 75 mi., half of which is an improved highway of modern construction. Transportation has always - been a large item of expense in carrying on operations in the district. Valuable ore is said to have been discovered in the Mogollon Mountains as early as 1870 but the first regular prospecting was carried on in 1875, by James C. Cooney, a sergeant from Fort Bayard. His discovery of rich silver-copper ores in the region of Mineral Creek led to the establishment of the Camp of Cooney. Remote from any settlements where there was a semblance of law and order, and harassed by the Apaches, development was slow and nearly 10 years elapsed before the village of Mogollon was established on Silver Creek. Prospecting in this section of the district had disclosed the outcrops of several promising veins containing silver-gold ores. Among the early claims located were the Last Chance, Top and Confidence, on what has proved to be the most productive vein in the district.

Jan 3, 1924

By R. W. Raymond

The Mining Law of New Pork, contained in Title XI., Chapter IX., Part One of the Revised Statutes, is as follows: Section 1. The following mines are, and shall be, the property of the people of this State in their right of sovereignty : (1.) All mines of gold and silver discovered, or hereafter to be discovered, within this State. (2.) All mines of other metals discovered, or hereafter to be discovered, upon any lands owned by persons not being citizens of any of the United States. (3.) All mines of other metals discovered, or hereafter to be discovered, upon lands owned by a citizen of any of the United States, the ore of which, upon an average, shall contain less than two equal third parts in value of copper, tin, iron, and lead, or any of those metals. Sec. 2. All mines and all minerals and fossils discovered, or hereafter to be discovered, upon any lands belonging to the people of this State, are, and shall be, the property of the people, subject to the provisions hereinafter made to encourage the discovery thereof. Sec. 3. All mines of whatever description, other than mines of gold and silver, discovered, or hereafter to be discovered, upon any lands owned by a citizen of any of the United States, the ore of which, upon an average, shall contain two equal third parts or more, in value, of copper, tin, iron, and lead, or any of those metals, shall belong to the owner of such land. Sec. 4. Every person who shall make a discovery of any mine of gold or silver within this State, and the executors, administrators, or assigns of such persons, shall be exempted from paying to the people of this State any part of the ore, produce or profit of such mine for the term of twenty-one years, to be computed from the time of giving notice of such discovery, in the manner hereinafter directed. Sec. 5. No person discovering a mine of gold or silver within this State shall work the same until he gives notice thereof, by information in writing to the Secre-

Jan 1, 1888

By AIME AIME

NO ADEQUATE salary scale, at the present time, can ignore the increase in the cost of commodities 'during the last few years or- afford to assume that this increase is merely temporary. A study of the change in prices and wages during and after the Civil War is of interest in connection with changes that have taken place from 1913 to 1919. The curves on the accompanying figure, based on reports of the War Industries Board and Department of Labor, show these changes. During the Civil War retail prices rose to 164,2 per cent. of the prices of 1860, during the next 8' or 10 years. It is interesting to note that the rise in wages during the Civil War was almost simultaneous with the rise in the prices of commodities. During the World, War, the rise in wages has lagged about a year behind the rise in prices. Furthermore, in the period immediately, following the Civil War, wages continued to rise after prices started to fall, The present price level is not considered merely temporary by such of our Government agencies as the Department of Labor and the Federal Reserve Board or by such economists as Irving Fisher' and J. S. Holden.2 Sub-

Jan 1, 1920

By C. A. Stetefeldt

The purpose of this paper is to convince the managers of silvermills that their customary reports in regard to the percentage of silver saved are far from the truth. It may be unpleasant for them to have the proofs of this fact brought before the public, and for this rezson the author refrains from giving the names of the mines and mills from which the statistics here recorded were obtained. It may be asked: What is gained by informing the stockholders of our silver-mines that they receive incorrect reports? Will this increase their dividends or lessen their assessments? In the first place, it is always better to publish honest facts than fiction. In the second place, many superintendents believe in the correctness of their reports, and have no idea how much they deceive themselves. Finally, the knowledge that hitherto unexpected losses of silver take place may lead to the adoption of methods by which these losses are greatly reduced. These remarks refer also to smelting-works. The present paper, however, is concerned exclusively with amalgamation and lixiviation. The first and most important error is found in the inaccuracy of the commercial assay; the second in the incorrect sampling of tailings in amalgamation. Further, mills not doing custom-work, but reducing exclusively ores from mines to which the mills belong, are in the habit of weighing the ore only approximately and without making moisture-tests. Thus, a correct basis for calculating the actual percentage of silver extracted is lacking. The superintendent, then, finds it convenient to report the apparent extraction, i.e., the extraction indicated by comparing the value of the roasted ore, minus soluble salts, with the value of the tailings. How many errors are thereby committed it is not necessary to point out.

Jan 1, 1895

Charles Mather MacNeill, President of the Utah Copper CO. and of the Chino Copper Co., and a life member of the Institute since 1899, died at his home in New York on March 17, after a very brief illness with pneumonia. Mr. MacNeill was born at Oak Park, Ill., in 1871, and began his connection with mining enterprises immediately after graduating from high school, his first position being that of cashier with the Pueblo Smelting and Refining Co. He later went to Aspen, Colo., as manager of the Holden lixiviation plant. In 1893, he went to Cripple Creek as manager of the Lawrence Reduction Works, in which Mr. Holden and the late Capt. J. R. DeLamar were large owners. It was at this plant that Mr. Jackling became associated with him. The plant was destroyed by fire and, early in 1894, Mr. MacNeill became associated with Messrs. Spencer Penrose and Charles L. Tutt in a plan to finance and erect a chlorination plant at Colorado City, Colo., for the treatment of Cripple Creek ores. This plant was erected and was known as the Colorado-Philadelphia Reduction Works. Mr. MacNeill was general manager of the plant, Mr. Tutt having been president and Mr. Penrose, secretary and treasurer. The plant was very successful and was expanded, hally being reorganized under the name of the United States Reduction & Refining Company. Late in 1903, or very early in 1904, D. C. Jackling called the attention of Messrs. MacNeill and Penrose to the copper properties in Bingham Cañon, Utah, which have since become the main properties of the Utah Copper Co. After extended examinations and milling tests, these properties were bought, Mr. MacNeill becoming president of the Utah Copper Co., Mr. Penrose, secretary-treasurer, and Mr. Jackling, general manager. Mr. MacNeill remained president of the company to the time of his death. Mr. MacNeill was also a director, a member of the executive committee, and was largely interested in the Ray Consolidated Copper Co.; he was also president and a member of the executive committee of the Chino Copper Co. He had a variety of other mining interests, but the ones mentioned were distinctly the meost important. He was a director

Jan 1, 1923

By O. Nomland

The work of The Bahrein Petroleum Company, Ltd., on Bahrein Island consisted mainly in continuing development work and prospecting previously reported. The exploratory work, however, has been greatly minimized and new wells are being drilled, chiefly for the development of larger production; 20 wells had been completed by the end of 1935 and 8 were being drilled. In addition to what has been referred to as the ''main pay," two deeper productive horizons have been discovered, which apparently will greatly increase the potential of the field although the areal extent of this lower production has not yet been determined. The proven acreage of the "main pay" is more than 12,500 acres. Current production (principally from the upper horizons) is about 13,400 bbl. a day. The construction of a 10,000-bb1.-a-day refinery has begun and is to be in operation by July, 1936. It is expected that the capacity will be considerably increased at a later date. The construction of office buildings and a permanent camp has been almost completed. In Saudi Arabia the California Arabian Standard Oil Co., a wholly owned subsidiary of the Standard Oil Company of California, spudded in a well in April, 1935, near the village of Dammam, on the Persian Gulf coast of A1 Hasa. Although several important showings of high-gravity oil and considerable gas have been found, the well is not yet considcred a commercial producer. Dammam well No. 2 has been started farther south on the same structure. A great deal of reconnaissance and some detailed geological work has been completed during the last three field seasons. In order to overcome difficulties of transportation over the desert sand, unusual methods have been used. The parlies penctrating the interior by the use of automobiles and trucks have been supplied with gasoline and provisions by caravans of camels. Mail and supp1ies of lighter weight urgently needed have been carried to the field men by an airplane operated by the geological division of the company. Each party has been supplied with a radio receiving and transmitting set to keep in contact with the airplane as well as with geological headquarters at Jubail on the coast of A1 Hasa.

Jan 1, 1936

In an address delivered at Atlantic City, N. T., Dec. 5, 1918, M. L. Requa, General Director, Oil Division of the United States Fuel Administration, said: We face a new era with all its uncertainties. We have arrived at the period of reconstruction and are face to face with the problems concerning which we have so often speculated during the past four years. In all this reconstruction work the United States must bear an important part. We are looked upon to lead the way, to blaze the trail and our actions will have a profound influence upon the rest of the world. If we are to succeed, even in part, we must not be ashamed to practise economy; we must not despise the clay of small things; the little savings; we must have the closest cooperation between Government and industry. Just as truly do we need civic awakening. All that we have ever fought for, the liberty of the world, is comprehended in the ballot; and yet how lightly we have held this great privilege! We need, if we are to reap in full the benefits of the past 18 mo., an awakened civic consciousness; a jealous guarding of government; a resolution that we will, each and all, perform to the full the duties imposed upon us by Democracy; that we will perform more completely the obligations resting upon us as citizens. During the war, industry, through sane cooperation and intelligent effort, has accomplished results possible of attainment in no other way. Government and industry have worked hand in hand and pointed the way o to future activities which, if realized, can but be most highly beneficial to all. If Government and industry are to fulfill their respective duties satisfactorily, it is obvious that there should be complete mutual confidence. Industry must not attempt to "put something over"-and Government must treat with industry upon the high plane that has characterized the public utterances of the President during the war. The individual who cannot conform to these high ideals should have no place in industry, and equally no place in Government. If the dignified and broad princi-

Jan 2, 1919