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By Mario Bergeron

L'exploration géologique pour les EOP (EOP: platine, palladium, iridium, osmium, ruthénium, rhodium) requiert avant tout des méthodes appropriees à la mesure de ces élémenIs. L'approche analytique choisie doit tenir compte de plusieurs facteurs, les plus importants étant: le type de materiel analysé, sa representativite, la sensibitite de la methode et les cotits reliés à son utilisation. Dans cette optique, plusieurs démarches ana/ytiquessont possibles, toutes requérant une étape de préconcentration. L 'une des plus adéquate consiste à effectuer une préconcentration par fusion plombeuse suivie d'une analyse par émission au plasma, cette procédure permettant de mesurer Ie platine, la palladium et Ie rhodium à des couts compétitifs (15 $/échantillon). Advenant 10 presence de teneurs appréciables de l'un ou plusieurs de ces éléments, une préconcentration par fusion au sulfure de nickel suivie d 'une analyse par activation neutronique assure alors la mesure de tous les EGP ainsi que celie de l’or (90 $/échantillon). Il est important de noter que Ie nickel, ades teneurs superieures à 4%, interfère au cours de l'étape de préconcentration par fusion plombeuse, ce qui se traduit pas sous-dosage des concentrations en platine, effectivement presentes dans l'échantillon. Ainsi, les géologues à la recherche d'EPG dans des environnements géologiques riches en nickel devraient s'assurer que l'analyse utilise, au cours de l'étape de préconcentration, une fusion au sulfure de nickel.

Jan 1, 1990

By R. K. Collings

Mineral wastes from the mining, metallurgical and chemical processing industries in Canada amount to about 800 million tonnes annually. Such wastes often are largely non-metallic in composition and are of interest for traditional non-metallic mineral uses and applications. Mineral waste disposal and maintenance are costly; furthermore, these wastes may pollute groundwater, rivers and lakes. These factors and an increased appreciation of the potential utility of some mineral wastes have stimulated research in this area.

Jan 1, 1984

By Yi Yang, Mark Zoback

"We report laboratory studies of the time-dependent deformation of core samples from four different formations in the Williston Basin - the Lodgepole formation, the Middle and Lower Bakken formations and Three Forks formation. The laboratory tests reveal varying amounts of viscoplastic deformation in response to applied differential stress. The time-dependent deformation is generally greater in rocks with higher clay and organic content, and can be described by a power-law function. Because the magnitude of the creep strain is linearly proportional to the applied differential stress, we can utilize viscoelastic theory and geophysical logs to estimate the degree to which tectonic stress is affected by viscoplastic stress relaxation. We suggest that viscoplastic stress relaxation results in the Upper and Lower Bakken Formations act as frac barriers during hydraulic fracture stimulation in the Middle Bakken, but the Lodgepole and the Three Forks Formations are not frac barriers.INTRODUCTIONHorizontal drilling and multi-stage hydraulic fracturing in shale reservoirs are critical for successful exploitation of ultra-low permeability shale gas, tight gas and shale oil reservoirs. Characterization of the mechanical properties of the reservoir rocks is essential to understanding the behavior of rocks during drilling and completion. Previous laboratory studies have shown that the timedependent deformation in clay-rich shales can be characterized as linear/viscoelastic deformation (Chang et al., 1997; Hagin and Zoback, 2004a, b; Sone and Zoback, 2013b, 2013c). Sone and Zoback (2013c) showed that laboratory measurements of time-dependent deformation in various gas shale reservoir rocks, and demonstrated that the viscoplastic deformation of these rocks can be characterized by a power-law function. They interpreted the results in the framework of linear viscoelastic theory to quantitatively assess the geomechanical effect of viscous time-dependent deformation over engineering and geological time scales. (Sone and Zoback, 2014) further extended the theory and proposed a viscous relaxation model that can be applied to predict the continuous differential stress magnitude using the geophysical logs. They tested the validity of their model by comparing the stress prediction with the occurrence of drilling induced tensile fractures (DITFs) and the vertical hydraulic fracture penetration observed from microseismicity."

Jan 1, 2015

By D. V. Ziehlke, J. M. Franklin, T. M. Gordon, A. G. Galley

The Snow Lake-Wekusko Lake region of northern Manitoba conta ins numerous lode gold occurrences, including the largest gold deposit in the Churchill Prov ince, the Nor Acme mine. The Aphebian volcanic and sedimentary rocks of this region are comprised of submarine volcanic strata, overlain by turbidites, both of the Amisk Group, and fluvi atile sedimenta ry strata and bimodally composed subaerial volcanic rocks of the overlying Missi Group. Gold occurs as: 1) accessory gold in volcanogenic massive sulphide deposits, 2) lode gold in shear zones related to sy n- to post-FI thrust fa ults, and 3) lode-gold associated with post-F2 fault . An alteration a emblage of biotite, al bite and calc ite is associated with both groups of lode-gold deposits, and has been superimposed on the regionall y-developed metamorphic assemblages. AJthough these deposi ts are spatial ly related to britt le-ductile faul ts of different initial ages, they appear to have all fo rmed after the major period of reg ional fo lding and metamorphism, and thus may be penecontemporaneous. The alteration is different from the sericite-ankerite-quartz assemblage that is typically associated with gold deposits in Superio r Prov ince. Deposits in thi s area of Churchill Prov ince may have formed either at a higher temperature or a deeper structu ra l level than tho e in Superior Prov ince.

Jan 1, 1986

By T. Johnson, D. Kelley, J. Graham

"Hydrometallurgical processes can be exceptionally corrosive. Conditions associated with metal extraction and refining require materials of construction that can withstand process acids and acid chlorides at temperatures up to 90°C (194°F). Process vessels, piping, scrubbers and ducting can be rapidly compromised in these aggressive environments if not designed with care. Design engineers are challenged to find materials that can stand up to hydrometallurgical processes especially for copper, zinc, nickel, cobalt and uranium. This paper will evaluate material solutions to determine which provides attractive economics for initial procurement as well as high durability for reasonable life cycle costs.INTRODUCTIONMining activity in a number of metal ores has been running quite high over the last few years. In particular, those metals that employ acid functional extraction processes such as copper, nickel cobalt and uranium have been particularly active.The world’s largest nickel mine – the massive $4.76 billion Ambatovy nickel mine on the African island nation of Madagascar is nearing completion. When it reaches its full production capacity in 2013, the mine will produce 60,000 MT/yr of nickel and 5600 MT/yr of cobalt. Coming on the heels of the Ambatovy project is the Long Harbour Processing Plant in Newfoundland, Canada which will process the ore from Vale’s Voisey Bay mine in Labrador. Voisey’s Bay is expected to generate more than 50,000 MT/yr of nickel ore when it starts up in 2013. Next up will be the Boleo project in Mexico on the Baja peninsula. When commissioned in 2013, the $858 Million Boleo project is expected to produce 60,000 MT/yr copper, 3100 MT/yr cobalt, 36,000 MT/yr zinc and 100,000 – 250,000 MT/yr manganese carbonate.High nickel alloys and rubber lined steel have been used for decades to design corrosion resistant equipment for mineral processing environments. These materials demonstrate reasonable resistance to corrosion for most environments. Unfortunately, higher nickel alloys are quite expensive. Rubber lined steel is a bit more affordable but requires continuing service over time which ultimately drives up its cost as well. FRP (Fiberglass Reinforced Plastic) has also been used extensively in mineral processing for tanks, piping and ducting employed in aggressive environments. Today, more and more design engineers and material specifiers are calling for FRP composites for both new and replacement equipment used in the refining and processing of a variety of metal ores."

Jan 1, 2012

By C. D. M. Chisholm

IN discussing stope filling, or backfilling, at the Sullivan mine, at Kimberley, B.C., a brief description of the problem will first be presented. The Sullivan orebody is a replacement in quartzite, with the ore con-forming, for the most part, with the bedding. The dip of the vein, apart from local irregularities, averages about 15 degrees near the outcrop in the southwest section of the mine, and steepens to almost 40 degrees at the northeast end of the mine. The thickness varies from a few feet to over 200 feet at the widest sections. The mineable length along the strike has averaged about 4,000 feet between the 4,600 and 3,900 levels-the section under discussion in this paper. To date, 28,000,000 tons of ore have been mined by the room-and-pillar method. Prior to 1930, all ground opened up had been supported by ore pillars, left during mining operations. From that time, the recovery of the ore from these pillars has been given serious consideration. Backfilling, as being carried on today, is the result of this study and is being done for two reasons: (1) to allow extraction of the ore pillars, and (2) to minimize subsidence of the hanging-wall rock, except where forced caving is found desirable. PRELIMINARY DEVELOPMENTS LEADING TO BACKFILLING When the Sullivan orebody was first opened up, early in the century, there appeared to be low-grade sections of the vein sufficient in extent to serve as permanent support for the roof. However, as mining extended into sections of the vein that showed continuous ore over greater areas, wooden cribs, filled with waste and low-grade ore, were erected. In some stopes, these cribs were as large as 40 ft. by 100 ft. in plan and from 50 ft. to 60 ft. in height, but it was soon realized that this method of support was inadequate. As mining progressed, it was found necessary to leave ore pillars, which eventually became the sole system of support. At first, these pillars were left at irregular intervals, but later they were laid out at definite locations on the mine plans, and these locations were adhered to as closely as mining would permit.

Jan 1, 1941

By Jacques Nantel

"The molybdenite property of Brynnor Mines Limited, Boss Mountain Division (wholly-owned subsidiary of Noranda Mines Limited), is situated approximately 360 miles northeast of Vancouver on the east slope of Takom-kane mountain in British Columbia's Cariboo District. Orebodies at the deposit fall into two categories; quartz breccia, and veins and stringers. The development of the breccia ore zone was started in June, 1964. The bulk of the ore is being mined from the stringer ore zone. The ore-body has been divided into 100-foot stopes and pillars. A sub-level blasthole method is used and the broken ore is handled in drawpoints and scram drifts. The development, drilling, blasting and handling of the ore are reviewed. The future pillar recovery operation is also analysed. The paper is also concerned with a scheduled shaft sinking program."

Jan 1, 1970

By D. R. Boyle

"The Murray Brook precious metal (Au, Ag) gossan deposit is one of nine supergene mineral deposits that have developed over polymetallic massive sulfide deposits in the Bathurst Camp of New Brunswick. Reserves consist of 1.9 Mt of gossan containing 1.53 g/t Au and 65.9 g/t Ag. The supergene zone at Murray Brook consists of six distinct units: a) altered massive sulfide, b) pyrite-quartz sand, c) massive sulfide gossan, d) disseminated sulfide gossan, e) ferruginized wallrock, and f) leached bedrock. The massive sulfide gossan constitutes the main body of economic mineralization and consists of goethite, primary quartz, secondary amorphous silica, K-Fe-Pb-As- Sb-Ag hydrated sulfate and oxide minerals (beudantite, plumbojarosite, jarosite, bindheimite, scorodite), trace cinnabar, and cassiterite of primary origin. The order of stability of sulfide minerals during oxidation was pyrite _ arsenopyrite _ galena _ Bi-Sb sulfosalts _ chalcopyrite _ tetrahedrite group _ sphalerite.Two mass balance techniques (isovolumetric and conservative element) indicate elemental depletion in gossan relative to primary ore in the order: S>Cd=Zn>Cu=Mn>Na=Ca>Fe=Al=V> Mg= K=Se=Hg>Pb>Ti>Ag>Mo=P>Ba; and enrichment in the order Au>As>Sb>Si>Bi. Tin, as cassiterite, is conservative.Mineralogic and paleomagnetic data suggest that the gossan deposit formed under a warm temperate climate throughout the Pliocene. The rate of oxidation and the compositional nature of the ore was significantly influenced by: a) the position of the primary sulfide zone in a downward moving hydrological system, b) primary sulfide composition and zonation that promoted the development of a strong electrochemical oxidation system, and c) pronounced intercalation of carbonate and sphalerite mineralization in sulfide zones, which promoted rapid development of secondary porosity, permeability and downward flow of oxygenated groundwater.During progressive oxidation and physico-chemical erosion of the gossan zone, Au was transported downward in groundwaters, probably as a Auo colloid complex, to be concentrated in the lower horizons of the gossan profile. The precipitation of Au was greatly increased in the pyrite/arsenopyrite zones. Gold concentration was multi-cyclic with continual dissolution and nucleation of the metal until final concentration in the void structures of the gossan. Leaching experiments and microprobe analyses indicate that Au is present in the gossan as submicron composite sols of Au-Ag-silica."

Jan 1, 1995

By D. A. McIsaac

In these days, when mass production seems to be the watchword of all industrial companies, nothing is left undone to attain this end. Transportation, where necessary, becomes a question of very great importance. For this reason every mechanical contrivance known to man is employed, with its resultant advantages. So successful has man's ingenuity been that, offhand, we are inclined to say that practically all transportation ?On a large scale is done mechanically, that is, where speed and economy are desiderata. Granting this, one would think that to read a paper on the horse before your honourable and highly technical Society would surely be a waste of time, and that any Company employing old-fashioned 'horse' power would certainly be very much behind the time, to say the least. However, the fact remains that the biggest industry in our country today-coal mining-must use horse power to a great extent, being compelled both by considerations of economy and by necessity. For this reason,' in the production of coal under present conditions, the pit horse is of great importance to this industry and is to be considered seriously as one of the units that help to make coal mining a success or a failure. Hence, in employing horses as a power for transportation, care must be exercised in selecting the animals, and the care of this power must be considered as seriously as any other department of such an organization. In selecting a pit horse, several things must be borne in mind, that is, one must get as much horse power as possible in as compact a form is practicable. This determines the type of horse we must use, which is of very great importance under our present conditions of coal mining. With low roof, steep grades, and forced production, a distinct type of animal must be selected.

Jan 1, 1930

By Thomas J. Ferree

"IntroductionThe objective of this chapter is to provide important criteria relating to the operation and maintenance of spiral concentrators and Reichert cones, so that optimum performance can be achieved and maintained in a mill circuit. Little space will be devoted to the theory of the forces of separation or the technical details of the devices, as that in(ormation is available from other sources. The discussions in this chapter will be presented in a manner that should be interesting and useful to anyone who may be exposed to these methods of gravity separation. It is most important for the reader to understand that each application of the equipment should be considered on its own merit, as no two suites of minerals respond exactly alike in mineral processing circuits. The information herein should be useful as a guide toward increasing the metallurgical efficiency of the processes, irrespective of the type of minerals being concentrated.It is highly recommended that certain tools be made available to the personnel responsible for metallurgical performance of the spirals and cones; these include a set of standard type laboratory screens, a medium quality petrographic microscope, and a vanning plaque or gold pan. These devices, when used in conjunction with a basic understanding of the mill circuit, provide immediate knowledge on the characteristics of any sample in the mill circuit. The information gained by visual evaluation of sized fractions of products can solve many of the basic problems of mineral beneficiation, and at the same time increase the interest of the non-technical personnel associated with the plant operation. There are many problems associated with obtaining satisfactory performance from a mill operation. Many of the problems have to be solved using a technical approach. Some of the problems, however, can be solved with practical knowledge and common sense. It is hoped this chapter can provide a guide to both techniques."

Jan 1, 1989

By D. R. Boyle

"Abstract - The Murray Brook precious metal (Au, Ag) gossan deposit is one of nine supergene mineral deposits that have developed over polymetallic massive sulfide deposits in the Bathurst Camp of New Brunswick. Reserves consist of 1.9 Mt of gossan containing 1.53 g/t Au and 65.9 g/t Ag. The supergene zone at Murray Brook consists of six distinct units: a) altered massive sulfide, b) pyrite-quartz sand, c) massive sulfide gossan, d) disseminated sulfide gossan, e) ferruginized wallrock, and f) leached bedrock. The massive sulfide gossan constitutes the main body of economic mineralization and consists of goethite, primary quartz, secondary amorphous silica, K-Fe-Pb-As- Sb-Ag hydrated sulfate and oxide minerals (beudantite, plumbojarosite, jarosite, bindheimite, scorodite), trace cinnabar, and cassiterite of primary origin. The order of stability of sulfide minerals during oxidation was pyrite > arsenopyrite > galena > Bi-Sb sulfosalts > chalcopyrite > tetrahedrite group > sphalerite.Two mass balance techniques (isovolumetric and conservative element) indicate elemental depletion in gossan relative to primary ore in the order: S>Cd=Zn>Cu=Mn>Na=Ca>Fe=Al=V> Mg= K=Se=Hg>Pb>Ti>Ag>Mo=P>Ba; and enrichment in the order Au>As>Sb>Si>Bi. Tin, as cassiterite, is conservative.Mineralogic and paleomagnetic data suggest that the gossan deposit formed under a warm temperate climate throughout the Pliocene. The rate of oxidation and the compositional nature of the ore was significantly influenced by: a) the position of the primary sulfide zone in a downward moving hydrological system, b) primary sulfide composition and zonation that promoted the development of a strong electrochemical oxidation system, and c) pronounced intercalation of carbonate and sphalerite mineralization in sulfide zones, which promoted rapid development of secondary porosity, permeability and downward flow of oxygenated groundwater.During progressive oxidation and physico-chemical erosion of the gossan zone, Au was trans- ported downward in groundwaters, probably as a Auo colloid complex, to be concentrated in the lower horizons of the gossan profile. The precipitation of Au was greatly increased in the pyrite/arsenopyrite zones. Gold concentration was multi-cyclic with continual dissolution and nucleation of the metal until final concentration in the void structures of the gossan. Leaching experiments and microprobe analyses indicate that Au is present in the gossan as submicron composite sols of Au-Ag-silica."

Jan 1, 1995

By L. Chunpongtong

The Athabasca oil sands mineable resource is located in northeastern Alberta, Canada. In oil sands mining, the ore zone is regulated to have a minimum mining thickness of 3 m and a cutoff grade of 7 wt.%. The current algorithm that is widely used to flag ore zones and waste zones tends to overestimate oil reserves and causes low-grade ore to be processed. This paper presents the development of a more complex algorithm that is more representative of the actual oil found during operations and that can prevent low-grade ore from being sent for processing.

Jan 1, 2014

By J Zhou

Based on the mineralogical characteristics and mineral processing techniques required, gold ores can be classified into 12 types, including gold placers, quartz vein-lode ores, oxidized ores, silver-rich ores, iron oxide copper gold ores, porphyry copper gold ores, iron sulphide ores, arsenic sulphide ores, antimony sulphide ores, bismuth sulphide ores, telluride ores and carbonaceous sulphide ores. The bulk mineralogy and gold deportment of each ore type is different and may have a significant impact on ore processing and metal extraction. This paper summarizes the bulk mineralogy and gold deportment in some major types of gold ores and discusses the potential impact of gold deportment on gold metallurgy.

Jan 1, 2011

By F. W. Guernsey

Of all the elements, sulphur occupies a place by itself. It is mined in situ, in such quantities and of such purity that, as regards the tonnage produced, it is the first of any element on the list. Iron and coal the great tonnage producers, are combinations of elements, while sulphur is mined and marketed almost chemically pure. It is sold, in large quantities, commercially, calling for a purity of 99.5 per cent while for medicinal purposes, the Pharmacopoeia requires only 99 per cent. purity. It is a very common commodity, and like many common things is of extreme importance, in the progress of our civilization. The substance has been known from the earliest times, the word sulphur being derived from the Sanskrit Culvari", hence the Latin Sulphur. Commercially it is also called brimstone, this word being a derivative of the Anglo-Saxon Bryne Stane or burning stone. From our younger days, we have been more or less familiar with the mineral. On the spiritual side being threatened, if we did not behave ourselves, with an ultimate consumption in a lake of fire and brimstone, (which in moments of reflexion was not pleasant to contemplate) while our bodily ills were taken care of by inward applications as a spring medicine. In both instances, the effect required, was generally attained. Sulphur occurs in nature, both free and in the combined state, it being estimated that it forms, over one tenth of one per cent of the first ten miles of the earths surface. (I do not know who did the estimating and it is not guaranteed).

Jan 1, 1923

Mine Safety in Chile ?Since the year 2000 fatality rate averages 34 per year ?1% of world mining labour force but 8% of world?s mining fatalities San Jose Mine Safety ?From 1998 to 2010 eight fatalities ?In 2003 mine inspectors recognized no second means of egress and a raise system was developed ?In 2006 182 workers were injured, 56 of them seriously ?In January 2007, there was a fatality after a rock burst, and the government ordered the mine closed ?Less than a year later the mine was back in operations. It had not complied with some of the basic safety measures ordered. One of those measures was to complete the escape way ladder.

May 1, 2011

By R. Mulligan

"The Cordilleran tin belt extends from the Seward Peninsula in westernmost Alaska to Mexico. Throughout the Canadian section, tin occurrences are mainly confined to a belt along the northeastern fringe of the Western Cordilleran sub-region; the boundary of this sub-region with the Eastern Cordilleran sub-region is most simply defined as the practical eastern limit of granitic and metamorphic rocks. The stratified rocks underlying this restricted belt are mainly late Precambrian and early Paleozoic miogeosynclinal sedimentary rocks, which are more or less metamorphosed but otherwise are generally equivalent to the less severely deformed rocks underlying the Eastern Cordilleran sub-region. They contrast with Late Paleozoic - Mesozoic eugeosynclinal volcanic-sedimentary assemblages farther west, but the granitic intrusions throughout are mainly of Late Mesozoic age. Thus, narrowly defined, the tin belt largely coincides with a lead-zinc-silver metallogenic province, whereas copper deposits characterize the eugeosynclinal regions to the west. In addition to the tin occurrences, which include the Sullivan lead-zinc-silver mine, Canada's only significant producer, the belt contains all the beryllium, most of the tungsten and many Iithophile-type molybdenum occurrences. Several types of occurrences of each metal are represented. Lithium occurrences in the Canadian Cordillera are notably rare, and these few are insignificant."

Jan 1, 1971

By R. S. Adhikari

The changes in defects patterns or in element condition index during visual inspection of bridges are primary concerns for inspectors. This paper presents a new approach for change detection of defects in bridges by identifying changes in texture patterns through spectral analysis of digital images. The commonly used method for change detection is image differentiation. This subtraction method requires images to be of same size, scale, and rotation. However, no two images are same in real practices. Thus, image registration is required to align images and to produce change maps. This process is tedious and it is difficult often to achieve a good registered image. But, the change detection task can be readily modeled in frequency domain for texture patterns discrimination and also for quantifying their properties. This paper proposes a novel approach for change detection by transforming digital images into Fourier spectrum. In new coordinate system, 1-D signature functions can be drawn which facilitates easy comparison of textures in different directions. The proposed methodology provides useful tools for comparison of inspection history graphically and quantitatively. In practice, expensive sensors are used to detect subtle change in defect patterns. The proposed method can be used to detect any subtle change in defect patterns using digital images at much lower cost.

Aug 1, 2013

By A. J. Brown

This paper presents an economic evaluation of resin ion exchange and solvent extraction for the purification and concentration of uraniferous solutions derived from sulphuric acid leaching operations. Capital and operating costs are related to the uranium tenors of pregnant solutions. The conclusions drawn herein apply only to cases where resin and liquid ion exchange are technically feasible process alternatives. It is shown that solvent extraction is economically favoured for pregnant solutions at tenors greater than 0.90 gpl U3O8. Pregnant solutions with tenors below 0.35 gpl U3O8 are best treated by resin ion exchange. Between these concentrations, the economics are marginal and the favoured process is indistinguishable within the limits of accuracy of this study.

Jan 1, 1979

By W. A. Roliff

The renewed interest of the past few years in the Appalachian and Michigan oil provinces has not, as yet, created any marked increase in activity in Southwestern Ontario. During 1960 development drilling in-creased somewhat over 1959, but exploratory drilling decreased slightly. More attention was devoted to the deeper horizons, but lake drilling de-creased considerably. Oil production reached a new peak and gas production increased slightly. During 1960 an interesting oil and gas discovery was made in the Cambrian and gas discoveries six miles off-shore in the eastern part of Lake Erie were made in the Clinton-Cataract zone of the Silurian. This paper reviews activities during 1960, summarizes the discoveries made to-date and the pertinent exploration data relating to the prospects of the region and discusses some of the economic aspects of exploration and development. D URING the last few years there has •been a marked renewal of interest in the old petroleum

Jan 1, 1961

By W. J. Wright

Summary Statement The following notes on the geology of the Grand Lake coalfield are intended to be introductory to a second paper being read at this meeting, which paper will describe the earlier and the more modern mining methods. The coal industry of the Grand Lake coalfield is centred chiefly within a three-mile radius of Minto, but minor operations are dotted over an area of approximately 50 square miles extending easterly to the vicinity of Chipman and Coal Creek (see Figure 1). The coal comes from one seam of Pennsylvanian age. The seam varies in thickness from 16 to 30 inches and lies almost horizontal at depths of 0 to 125 feet. It has been mined and prospected over an area of approximately 150 square miles, but in a portion of this area the commercial possibilities have been destroyed by erosion. The industry is the oldest of its kind in North America, but it did not at tract particular publicity until about 1914. Since that date, mining methods have improved and the output has rapidly increased until, in 1934, it amounted to 271,335 long tons, and furnished employment for about 1,000 men (1). Approximately 73 percent of this amount was produced by the Minto Coal Company, the Miramichi Lumber Company, the Avon Coal Company, and Welton and Henderson, and 25 per cent by the Rothwell Coal Company, Harvey Welton Limited, G. H. King, the Reade Construction Company, and the Newcastle Coal Company. The remainder was produced by J. W. Carter, G. D. Crossman, T. H. Swift, C. S. Yeamans, and several other small operators. The coal is won by underground mining, except in the case of the Reade Construction Company, and a minor operation by Ashfield and Pieton, who have employed open stripping. It is mined only as required to fill definite orders, and is loaded directly into cars for shipment. In 1934, the larger mines did not operate full time, and the production could easily have been increased if markets had been available. The coal is sold in four grades: screened or lump, run of mine, slack, and stripping. The chief market is with the railways and commercial plants, with a fair amount for domestic purposes.

Jan 1, 1935