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By S. R. L. Harding

"Introduction0N MAY 2th, 1953, Socony Seaboard Pembina No. 1 well, located 70 miles west-southwest of Edmonton, was completed as a producer of high-gravity oil from the Cretaceous Cardinm sand. This event is possibly the most significant in the development of the oil industry in Western Canada since the Devonian discovery at Leduc in 1947. The result of the Pembina discovery and the follow-up drilling has been a tremendous increase in interest in the Cardium formation.Descriptions of the Cardium formation, as it occurs in the 'Central Foothills' and in the 'Southern British Columbia Foothills' have been presented by R. E. Folinsbee (9)-and C. R. Stelck (21), respectively. The purpose of this paper is to discuss the more regional aspects of the subject.The name Cardium was first used .as a stratigraphic term in 1863. Dr. James Hector ( l2), geologist attached to Captain John Palliser's exploratory expedition, gave the name 'Cardium to the whole section of marine Cretaceous beds exposed along the Bow river west of Calgary."

Jan 1, 1955

By J Dwyer, G Turner, D Pridmore, M Urosevic

Due to their ability to produce high-resolution images of the subsurface to great depths, seismic surveys provide critical inputs to almost all oil and gas exploration projects. However, with some notable exceptions, seismic surveys have rarely been used in mineral exploration. In the past, this was due to both technical and financial reasons. Significant developments on both fronts mean that seismic surveys can now offer substantial benefits to mineral exploration and mining, and surveys conducted for exploration can provide important data sets for mine planning over the life of a mining project.We present case history data that show that seismic surveys can greatly assist with mapping the 3D distribution of lithologies and alteration and, in favourable circumstances, directly detect mineralisation in and around mineral systems. As a result of their high spatial sampling density, seismic surveys are also highly effective at mapping structures that can remain undetected or poorly characterised by drilling alone. These structures may host or provide important vectors to mineralisation. They can also be particularly important when planning shafts, raise bores, declines, stopes and open pit walls. A further benefit of seismic surveys is that they can remotely provide information on geotechnical rock parameters that are used for rippability, slope stability, blasting and ground support.CITATION:Turner, G, Urosevic, M, Pridmore, D and Dwyer, J, 2015. Exploration and mining unified through seismic imaging, in Proceedings Third International Future Mining Conference, pp 117–122 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 4, 2015

The results expected from a longwall face can best be estimated from the ideal production rate, determined by the capacity of the equipment and the conditions in which it is installed, the effective operating hours, and the utilisation.The effective operating hours are determined by a number of scheduling factors which include the proportion of manned time to calendar time, the effective shift factor (effective time to manned time) and the move times.Analysis of the results achieved on the last 121 completed longwall panels in Australia (1984 onwards) shows a significant trend between 'actual tonnes/manned hour' and 'ideal production rate' (the measure of the capacity of the installation).Using 1982 'state of the art' longwall equipment, (the average in use in the seven year period), it should be possible to produce around 2.7M tonne/year ROM from a mine with one longwall. Few mines are achieving this.A review of production scheduling factors and general natural hazards affecting some mines suggests three things.1. Whilst some increase in average effective hours has followed the CIT decision, further improvement is possible at many installations.2. Many mines subject to general natural hazards, such as high gas make and high general stress, have found effective solutions and achieve the same utilisation as the overall average.3. A small number of faces within such mines have been severely affected, some less so. The most severe effects of natural hazards appear to be very site specific. This emphasises the need for detailed investigation of the causes, and development of means of predicting their presence. Only then can either satisfactory technical solutions be found to overcome the problems or prior decisions be chosen not to mine badly affected panels.

Jan 1, 1991

By J. Murray Riddell, George A. Morrison

THIS paper is a companion to the one by George A. Morrison on Mining a Deep Limestone Mine in Ohio.[+] Barberton is 8 miles west of Akron, Ohio, and 23 miles south of Cleveland. The underground mining of limestone at Barberton constitutes the world's deepest limestone mine. The stratigraphy is as follows: 0-20 ft. Loam, clay, sand and gravel. Water bearing. 20-40 ft. Fractured. sandstone. Water bearing. 40-110 ft. Sandstone with interbedded shale, slightly fractured. Water bearing. 110-314 ft. Sandstone with interbedded shale, slightly fractured. Water carrying. 314-2197 ft. Shale with occasional seams of sandstone, which varies in thickness from a few inches to 4 feet. Dry. 2197-2247 ft. Limestone. Dry. 2247-2742 ft. Dolomitic limestone. Dry. 2742-2767 ft. Salt. Dry. 2767- Dolomitic limestone. Dry. All of the strata dip to the southeast, about 0.5 per cent from the horizontal. The top 110 ft. of the crust is water-bearing. The rock strata are naturally fractured to a depth of 314 ft., sufficient to allow the passage of water. In the shaft-sinking operations, a stra was encountered at a depth of 520 ft., and flows of methane gas were pierced at depths of 1350 and 1952 feet. Specifications for the mine plant called for, in part, the sinking of two vertical shafts and a hoisting plant capable of producing at the rate of 300 tons per hour. No. I shaft is 550 ft. west of No. 2 shaft. Each shaft measures 8 by 17 ft. outside of steel. General features of the design (Fig. I) are: Principal set members, 6-in. H-section; connecting angles (studdles), 3/8 by 4 by 4-in. angle irons; spacing of sets, 8 ft. centers; spacing of bearer sets, generally, 160 ft.; bearers, of 12-in. I-beams. Each bearing set featured a concrete ring about the periphery of the shaft, steel to rock, and 8 ft. in height; permanent guides, 6 by 10-in. long-leaf yellow pine, 85 per cent heart. THE SHAFT-SINKING OPERATION The preliminary shaft-sinking work consisted of driving interlocked steel piling about the exterior of the shafts to depths of 35 and 32 ft., respectively, and of such horizontal dimensions as to ultimately permit the pouring of a concrete collar 2 ft. in horizontal thickness. Following the pouring of a shaft collar, a temporary wooden headframe for shaft-sinking purposes was erected. The head-frame, while ordinary, featured: (I) a storage pocket of 300 cu. ft. capacity with truck servicing facilities, and (2) pneumatically operated dump doors, which were actuated by the hoistman, thus caring for the dumping of the "ball-and-chain"

Jan 1, 1944

By William Reisz

Over the years as surface mining operations have become more sophisticated, angle drilling has become a more popular blast design technique, especially in areas where overburden and stripping ratios have increased. Another method of blast design is the staggered pattern, which greatly improves explosives distribution within the blast. While both methods present some engineering challenges, this paper will discuss how the two methods can be combined to enhance fragmentation, improve cast percentage, drill production ratios and highwall control. A practical engineering approach will be presented as well as a discussion on the discipline required to maintain a quality blasting plan.

Jan 1, 2002

By Stephen C. Tadolini, John P. McDonnell

"High-strength cable bolts have been used for ground support in underground coal mines for many years. Cable bolts are routinely used as secondary ground support in numerous longwall gateroad support applications, areas that possibly experience the most severe conditions in current underground coal mining. Additionally, when mining ground conditions deteriorate, engineers oftentimes recommend cable supports as a principal solution because of the established credibility for successful ground control. Nevertheless, there is still a reluctance to utilize non-tensioned cable supports as an effective primary roof support alternative.This paper provides historical and recently documented examples of non-tensioned cable supports utilized as an effective primary ground support method in a western U.S. underground coal mine, and it will continue the technical discussion between the differences of various degrees of tension in cable supports with respect to ground behavior and reactions.INTRODUCTIONResin-grouted cable supports are widely used to support difficult ground conditions throughout the world. Through the use of innovative applications and configurations they have proven to be a major paradigm shift in roof support and ground control technology in the U.S. (Tadolini and Koch, 1993; McDonnell et al., 1995; Tadolini and Gallagher, 1994; Tadolini and Trackemas, 1994)Today, the basic cable bolt support consists of a high-strength steel cable installed in bore holes that range in diameter from 25 to 50 mm (1 to 2 in) depending on the strand size and drilling equipment. Cables are offered in both bright and galvanized, for corrosion protection, and range in capacity from about 30 to 60 tons. An example of a resin-grouted cable bolt and the key components is shown in Figure 1. The steel cables are flexible and the support length is not limited by the height of the opening. Lengths of up to 10 m (32 ft) have been supported with high pattern densities when standing supports were not operationally feasible. The most common lengths are 3 to 5 m (10 to 16 ft). An important physical characteristic is that PC-strand has an ASTM minimum elongation requirement of 4%. For comparison purposes, the ASTM 432-08 Standard Specifications for Roof and Rock Bolts and Accessories specifies elongation requirements for traditional roof bolts are a minimum of 12% for grade 40, 9% for grade 60, and 8% for grade 75 materials, respectively. Traditional roof bolts can stretch and elongate twice the length that cable bolts can, which makes design considerations challenging."

Jan 1, 2010

By J. V. W. REYNDERS

THE principal manganese deposit of Russia, I one of the four principal sources of the world's supply, lies on the southern slope of the Caucasus Mountains, in what is now the Republic of Georgia, district of Sharopan. Tchiatouri, the principal town, is midway between Tiflis, the capital of Georgia, and Poti, the shipping port on the Black Sea, about 130 " miles distant. The deposit can be most easily visualized by thinking of a nearly horizontal coal seam about 6 ft. thick, outcropping on the slopes about 600 ft. above the Kvirila River. One of the accompanying illustrations shows the river, which nearly bi- sects the district, of approximately 50 sq. miles in area, and with its tributary streams makes the topography rugged, while in the background are the snow-capped peaks of the Caucasus range. Another of the illustrations gives a closer view of the outcrop. The roof and floor of the deposit are good, so the methods of working are quite similar to working a coal seam, especially as most of the mineral is soft enough to be mined with a pick. Little machinery is used, except small cars for underground transportation.

Jan 1, 1926

By Li Yang, Andre Cezar Zingano, Alberto Fronza

"Immediate roof control is very important to the security and stability of entries in coal mining. It is also the highest cost in the coal mining operation, and roof spalling is directly responsible for coal contamination. The immediate roof in the coal mines in the State of Santa Catarina varies in lithology and in the presence of structures, such as bedding planes, vertical fractures that cut lamination, sandstone, and siltstone boulders. The presence and crossing of these structures should influence the decision of the specification of the roof support. Furthermore, the variation of rock layer and quality of the roof must be immediately followed by the variation of support specification. This work aims to study the behavior of the immediate roof under different geological and structural conditions during the excavation of entries, including the changing of the geometry of the entry as a function of time. This includes the effect of vertical fractures that cross the bedding planes of the roof and the position of those fractures on the roof. The effect of time between excavation and installing support to stabilize the roof is also examined. This study uses empirical methodologies for support design and numerical methods to study the behavior of the roof when anchored to the different scenarios proposed. The results of this work show the importance of quality characterization of the roof in terms of the type of rock and its thickness and the presence of vertical fractures that cut the bedding planes of the roof immediately.INTRODUCTION The immediate roof in a coal mine can varies in terms of typology and structural features, like bedding plane spacing and vertical joints. The roof support must be specified based on the features of the roof layer and its classification. Unal (1983) and Mark, Molinda, and Dolinar (2001) suggest that the roof support design should be based on the rock mass rating (RMR) and coal mining roof rating (CMRR), which look at rock mass classifications. These methods are based on the beam-building approach, and the bedding planes are tied together using fully grouted bolt. The bolt can be pre-tensioned or not depending the time of the curing of the resin."

Jan 1, 2017

By Hori M, Komatsu T

In Japan, a small-diameter tunnel boring machine (TBM) of diameter 2.6 m applicable to a wide range of geology from hard rock to soft strata was developed with the purpose of reducing construction costs of headrace tunnels for small hydroelectric power stations. And in 1983, a demonstration test was carried out in the No. 1 headrace tunnel work of Hayakido Hydroelectric Power Station. The principal achievements in executing work are the following: (1) Although this TBM was a demonstration test unit, excavation advances averaged more than 200 m/month and exceeded the average 150 m/month with a conventional method. (2) According to PS velocity surveys after tunnel excavation the zone of loosening due to the TBM method was small enough to be ignored and was approximately one-half compared with conventional methods in rock of the same evaluation.

Jan 1, 1987

By A. Dale Marcy, Pamela L. Drake

Workers who perform routine welding tasks are potentially exposed to fume that may contain manganese. Manganese may cause respiratory problems and is implicated in causing the occurrence of Parkinson-like symptoms. In this study, a field colorimetric method for extracting and measuring manganese in welding fume was developed. The method uses ultrasonic extraction with an acidic hydrogen peroxide solution to extract welding fume collected on polyvinyl chloride filters. Commercially available pre-packaged reagents are used to produce a colored solution, created by a reaction of manganese(II) with 1-(2-pyridylazo)-2-naphthol. Absorbance measurements are then made using a portable spectrophotometer. The method detection limit and limit of quantification (LOQ) were 5.2 mg filter-1 and 17 mg filter-1, respectively, with a dynamic range up to 400 mg filter-1. When the results are above the LOQ for the colorimetric method, the manganese masses are equivalent to those measured by the International Organization for Standardization Method 15202-2, which employs a strong acid digestion and analysis using inductively coupled plasma-optical emission spectrometry.

By D. Richers

When modeling predictive pit lake chemistry, groundwater chemistry is integrated with the affected portions of the wall rock and chemistry of the lake in a complex series of mixing. Fractions of the solutions impinge upon fresh, unaltered or fractured and oxidized zones of the wall containing sulfide materials and/or soluble metal/metalloid salts. Changing conditions over the short term (biannually) and long term (decades) can drive reactions allowing for dissolution or precipitation of acid rock drainage and metal leaching (ARD/ML) constituents. Local zonal variations can result in a portion of the pit releasing materials into solution; whereas other portions of the lake might favor the formation of colloids or precipitants. The proportions and character of groundwater can drive the chemistry of the pit lake provided sufficient buffering capacity is available to temper the generation of ARD in the system. For sulfide-rich systems, reduction of oxygen by rapid inundation and consumption by sulfides is key to reducing the ARD/ML. This paper presents several models of a sulfide-rich wall rock system using a range of groundwater chemistries to show these constraints.

Jan 1, 2012

By J. F. T. Agapito

Stability in Exxon's Colony Pilot Mine in the Piceance Creek Basin, Colorado has been monitored by periodic pillar stress-determinations End roof-to-floor convergence measurements since 1971. Pillar failure has caused marginal stability in some areas of the mine. Measurements taken during the process of failure provided valuable information on the in-situ pillar strength and long-term behavior of the mine structure. Four pillars were reinforced by 32 mm (1-1/4 in) diameter tensioned grouted bolts to increase long-term stability in the northern area of the mine. Stability of this area is necessary because future plans envision its use as an exit/access and ventilation exhaust. Computer analyses were performed to help evaluate the effect of pillar reinforcement on long-term stability. Results indicate that bolting is particularly useful in stabilizing failed pillars, but its effects are significant only in the immediate area of the pillar. The projected significant decrease in deformation of two extensively failed pillars near a main entry indicates that bolting reinforcement will assist the long-term stability of the opening.

Jan 1, 1985

By D. D. Rabb

Originally, the term solution mining applied to a dissolution, washing, or "brining" of soluble salts such as halite (common table salt), potash or trona. After the mid-sixties, however, the definition has been expanded to include heap and dump leaching, in-place (in situ) leaching, removal of oil from tar sands, extraction of sulfur from deep wells by the Frasch process and the recovery of metalliferous solutions from geothermal sources. Solution mining is also known as borehole, non-shaft, or chemical mining; the extraction of soluble mineral values from a variety of ores using appropriate solvents and chemicals. Solution mining frequently involves chemical changes; for example, copper usually goes into solution as copper sulfate, gold and silver as a cyanide compound, and uranium as a sulfate or uranyl tricarbonate. The valuable constituent is removed from the solid body of the ore by mass transfer to a aqueous solution.

Jan 1, 1986

It is perhaps somewhat unusual for a contributor to comment on the authors' reply to his critique. However, I should like to return to a specific comment made by the authors. Award to Bob Laburn The Federation of Societies of Professional Engineers (FSPE) is pleased to announce that the 1984 FSPE Award for Services to the Engineering Profession was presented to Dr R. J. (Bob) Laburn at a function held on 14th February, 1984.

Jan 1, 1984

By A. U. Christensen

THERMODYNAMIC data for many of the common interoxidic compounds are seriously lacking, and appraisal of possible ceramic or metallurgical applications depends upon dubious estimates. In particular, high-temperature heat-content estimates may be invalid because of unknown phase-transformations. This paper reports experimental heat-content values above 298.15° K. for five interoxidic compounds-the aluminates of lithium and sodium (LiAlO2 and NaAlO2), the ferrites of lithium and sodium (LiFeO2 and NaFeO2), and lithium titanate (Li2TiO3), as obtained by the Bureau of Mines. Sodium aluminate, sodium ferrite, and lithium titanate were found to have previously unknown transformations in the crystalline state. The heats and temperatures of these transformations were evaluated as were also the heats and temperatures of fusion of sodium ferrite and lithium titanate. The heat-content results are assembled in both tabular and algebraic-equation form for use in conducting thermodynamic calculations at temperatures in the range 298°-2,000° K.

Jan 1, 1960

By Luben Xie, Lin Hu, Qiang Wang, Min Gan, Tao Jiang, Wenqi Li, Xiaohui Fan, Zhiyuan Yu

"Crystal precipitation behavior of calcium ferrite (CF) during iron ore sintering process along with the effect of cooling rate, SiO2 and Al2O3 on crystalline condensation were studied. The results show that CF, has strong ability of precipitation. The precipitation is barely affected by extenal factors. It begins to precipitate when the liquid phase cools down to about 1200oC. CF could crystallize rapidly at the cooling speed of 150 °C /min. Furthermore, decreasing of the cooling rate favors the development of crystal. Binder phase transformed from CF system to silicate system when SiO2 content was increased to 5~6%, with a constant basicity (R) 2.0. Increasing Al2O3 content could promote the precipitation of CF and the development of crystal.IntroductionCrystalline condensation is the last stage of sinter mineralization. It includes the processes that crystalline substance and amorphous substance precipitate from high temperature solution phase and the consolidation of material when melt cools down. During the crystallization process, minerals precipitate following the order from high to low melting point coupled with the decreases of free energy. Most of binder phase minerals and part of iron oxides crystallize in this process, which have an important influence on mineral composition and microstructure of sinter. They finally determine the sinter strength and metallurgical properties."

Jan 1, 2011

By H. R. Hoffman

SINCE slag is a necessary product of the reactive oxygen additions necessary to the present-clay quality steelmaking, the study of the control of its volume is being attempted. With other varying factors that may affect the volume of slag kept as nearly constant as possible, the object of this investigation is to determine what effect the one factor of varying the amounts of iron-ore additions and the time of the additions may have upon the volume of slag in producing an acid electric steel heat.

Jan 1, 1947

By M. R. Yalamanchili, C. A. Young, J. J. Kellar, W. M. Cross, J. D. Miller

Introduction Researchers have long speculated regarding the adsorption state of collectors on mineral surfaces. Only recently have analytical techniques become available that allow direct in situ analysis of adsorbed layers. With reactive internal reflection elements (IREs), Fourier transform infrared spectroscopy coupled with internal reflection spectroscopy (FT-IR/IRS) allows for unobtrusive investigation of the adsorbed layer (Harrick, 1979). This technique has been used both for the in situ identification of adsorbed species and for the direct calculation of collector adsorption density in real time from infrared spectral data (Miller and Kellar. 1988). The reactive mineral IRE serves both to internally reflect the infrared light and to act as a substrate at which collector adsorption can be monitored. Shown in Fig. I is a schematic of light being internally reflected in an IRE. As the light is totally reflected at the interface, an evanescent wave propagates a short distance (typically a few microns) away from the IRE, and sampling of the interfacial region occurs. Because of multiple internal reflections, great sensitivity can be obtained. Flotation systems for which this method has been demonstrated include CaF2/oleate, Al2O3/dodecylsulfate, CaCO3/oleate, ZnS/xanthate and KCI/octylamine (Miller and Kellar, 1988; Kellar et al., 1989, 1990; Miller et al., 1990). Of particular interest to flotation chemists is the conformational behavior of the alkyl chain of adsorbed collector molecules. In the simplest sense, conformation can bethought of as the relative flexibility of the hydrocarbon chain caused by rotations about carbon-carbon single bonds. The flexibility is described by the amount of gauche/trans conformations in the alkyl chain. Figure 2 shows examples of gauche and trans conformations (rotational isomers or rotamers) in a hydrocarbon chain. These two conformations are observed when the terminal methylene groups in any four-carbon subchain are on the same side (gauche) or opposites sides (trans) of the plane of the middle carbon-carbon bond. A gauche conformer (rotamer) is thus a state of maximum potential energy, whereas a trans conformer is a state with minimum potential energy. The difference between these states has been found to be approximately 0.5 to 0.8 kcal/mole (Mead et al., 1986). The relative number of butane molecules present as gauche conformers with respect to trans conformers can be calculated from the Boltzmann equation (Mead et al., 1986). At 25° C approximately 66% of the butane molecules are trans rotamers. [ ] However at 100° C, only 33% of butane molecules are trans rotamers. Exposing the hydrocarbon chain to a polar, rather than an a polar, medium should also cause an increase in the number of gauche butylene groups in a hydrocarbon chain, although this effect has been difficult to observe experimentally (Mead et al., 1986). Forming a crystalline hydrocarbon is equivalent to decreasing the temperature, which greatly increases the amount of trans butylene groups present in the chain. From the preceding discussion, a picture of the solution species of concern can be developed. The collector monomer should exhibit the greatest number of gauche rotamers and most likely will look crumpled or balled-up to reduce the surface area in contact with water. The micellar form is expected to be aggregated, with the hydrocarbon chain existing in a less polar environment. These characteristic conformational features have been examined by FT-IR spectroscopy for various liquid phases of alkanoic acids (Umemura et al., 1981; Cameron et al., 1982a; Yang et al., 1986; Wong, 1987; Wong and Mantsch, 1983; Cross et al., 1992), phospholipid membranes (Fringe Ii, 1980; Casal and Mantsch, 1985: Wong et al.. 1988;

Jan 1, 1994

By D. O. LIVINGTON

(Presented by invitation at a meeting of the Spokane Local Section of the institute, Feb. 17, 1912.) THE Pilares de Nacozari mine is located in Sonora, 75 miles south of Douglas, Ariz. The town of Douglas is on the International Boundary and is the place at which the ores from the Bisbee mines are smelted. The Moctezuma Copper Co. owns the mines at Nacozari, and the copper-concentrates shipped to the Copper Queen smelter, at Douglas, make a good smelting-mixture with the Bisbee ores. The Moctezuma Copper Co. and the Copper Queen smelter at Douglas, as well as the railroad from Douglas to Nacozari, are owned by the Phelps Dodge Co. The ore-deposit occurs in the form of a large ellipse with a major axis of approximately 2,000 ft. and a minor axis of about 600 ft., the major axis bearing about 90 W. of N. The whole of this ellipse is more or less mineralized; the surface being principally an iron gossan with some occasional copper-stains. Below the oxidized zone, which is not more than 50 ft. deep, the minerals are pyrite and chalcopyrite, with occasional seams of chalcocite, the latter being rare. There appears to be no well-marked zone of secondary enrichment, the oxidized gossan over the greater part of the deposit changing suddenly to what is apparently the original unaltered ore. The copper-values are concentrated around the perimeter of the ellipse, and it is principally around this perimeter that the mining is done. The ore mined averages a little more than 3 per cent. of copper, with a small amount of silver, less than an ounce per ton. Some ore of considerably higher grade than this has been shipped, however, but the above average is of the mill-run. The ore is wider near the two ends of the ellipse than along the sides, and is mined in some cases to a width exceeding 200 ft. The country-rock for the first vertical 500 ft is a volcanic acid breccia, probably rhyolitic; below

Sep 1, 1912

By E. P. Mathewson

W. W. (Pop) Adams' contribution is short and to the point. "I went to Pueblo about March, 1881, and started working for the Pueblo Smelting & Refining Co. in the sampling room, going from there to the assay and chemical departments, and ending in charge of the lead refinery on the night shift. I was there about two years, returning to California in 1883. The plant was under the management of Mather and Geist, plus Charley Ballard; Herman Schlapp was the metallurgist. Herman Schlapp's name remains prominently in my recollection of Pueblo for his never-failing kindness and charity to the young men who were trying to learn the Pb. game. John Allen, Walter Koehler, George Westcott, Charley Molson, and Alfred de Ropp were there with me. Schlapp and Koehler I have never seen since I left Pueblo; the others I have met often. , Alfred de Ropp I have often met-here, as he was manager of the Selby Smelting & Lead Co. of San Francisco, for years. 'He tells me that I gave him the rudiments. of American profanity at Pueblo; an apt pupil, for since then, by his own efforts, he has added largely to his vocabulary..

Jan 12, 1923