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By W. N. Hamilton

"Evaporites abound in the Western Canada sedimentary basin, recurring throughout the stratigraphic column and widely scattered over the basin region. Alberta, situated centrally over the basin, includes many of the evaporites within its borders, but only a few have the right geological conditions to form potential economic deposits of salt or gypsum. These include the Middle Devonian Elk Point Group and related evaporites, Upper Devonian Wabamun Group-Palliser Formation evaporites, and evaporites of the 'Triassic Charlie Lake and Whitehorse formations.Salt deposits underlie almost half of Alberta. The major deposits belong to the Elk Point Group, which includes thick salt units in the Lotsberg, Cold Lake and Prairie Evaporite formations. Another, younger salt deposit in the Wabamun Group has only local distribution. Elk Point salts have a maximum aggregate thickness of 430 m in east-central Alberta. The deposits deepen southwestward across the province, from minimum depths of210 m at Fort McMurray to 1820 m at Edmonton.The thickest, most extensive salt deposits are the upper Lotsberg and Prairie Evaporite salts. Both have excellent development potential. The upper Lotsberg is up to 150 m thick, consists of clear, very coarse crystalline halite with only minor impurities, and has a notable lack of non-salt strata in its succession. Analytical data for the Lotsberg Salt show extraordinary chemical purity. Prairie Evaporite Salt differs lithologically from the Lotsberg in having a significant non-salt component. The deposit is up to 200 m thick and consists of medium crystalline halite, brownish coloured and cloudy as a result of finely dispersed impurities. The main impurities-shale, anhydrite and dolomite-are most prevalent as interbeds in the salt succession, ranging from very thin laminae to beds several metres thick. Although of lesser purity, the Prairie Evaporite Salt is shallower, thicker and more extensive than the Lotsberg and the salt quality is quite acceptable for most industrial uses."

Jan 1, 1982

By J. A. Allan

OCCURRENCES of salt in Alberta have been mentioned and described by the writer in 1929 (l) and by Cole in 1930 (2). Brine springs occur at a number of places along the valley of Athabaska river north of latitude 56 degrees, and also on the south margin of Salt prairie, twenty-five miles west of Fitzgerald in the vicinity of the 60th parallel of latitude, which is the boundary between Alberta and the Northwest Territories. These salt springs were visited by Sir James Richardson in 1820, and in the same year D. W. Harmon stated that " ... clown Salt river there are several places where almost any quantity of excellent dean white salt may be taken with as much ease as sand along the seashore" (3). One hundred years later, in 1920, when the writer first visited these springs, the "dean white salt" which had accumulated about the springs was about 400 tons ( 4). This paper deals with a thick deposit of rock-salt which has been proved by drilling in the vicinity of McMurray. Particular attention will be given to a well drilled at Waterways early in 1936 by Industrial Minerals, Limited, when a continuous bed of rock-salt was penetrated with a thickness of 199 feet. As this paper is being presented, a salt plant is being completed and a production well is being drilled at the plant. < is salt deposit is in the vicinity of McMurray, close to the junction of the Clearwater and Athabaska rivets, in township 89, range 9, west of the 4th meridian. McMurray is about 240 miles northeast from Edmonton. As shown on Figure 1, Clearwater river, which rises at Methy portage, in Saskatchewan, enters Athabaska river at McMurray. Some three miles above the mouth of Clearwater river, the Hangingstone enters from the southwest. Waterways, where the latest salt development has taken place, is situated at the end of the Northern Alberta railway, a distance of 304 miles from Edmonton. This railway reaches the bottom of the Clearwater valley at Draper station, about 3 miles east of Waterways and near the mouth of Deep creek. The Draper bituminous sand plant is approximately half a mile east of Draper station. About one mile south of the townsite of McMurray, Horse river enters the Athabaska from the east.

Jan 1, 1937

By G. R. Guillet

Salt is restricted to five major beds in south western Ontario, totalling as much as 200 m in thickness. These beds are located at depths ranging from 270 m to 750 m below the surface, fringing Lake Huron and the Detroit River from Windsor to Kincardine, and extending inland as far as London. Manitoulin Island, the Bruce Peninsula and the north part of the Niagara Escarpment form the northeastern rim of the Michigan Basin, a major structural depression in which the salt was deposited 400 million years ago when much of North America was covered by the Silurian sea. Salt is mined underground at Windsor and Goderich; it is also brought to surface as brine through deep wells at Windsor, Samia and Goderich. Artificially- created caverns in salt beds are extensively used for storage of liquid hydrocarbons at Windsor and Samia.

Jan 1, 1984

By W. Gordon Muir

This paper deals with the exploration, development and current operations of the salt mine at Goderich, Ontario operated by the Sifto Salt Division of Domtar Chemical Limited. The rock salt is obtained from a bed 1,760 feet below the surface, 75 feet thick, extending under Lake Huron. Annual production is in excess of one million tons. Large mobile equipment is used. Details of this equipment, as well as the shaft layout, which permits the equipment to be lowered underground with a minimum of trouble are outlined. Mining, crushing and screening procedures' are rev1ewed. Reference is also made to productivity salt distribution and uses.

Jan 1, 1967

By K. Duckworth

"AbstractA new electromagnetic depth sounding technique was applied to the measurement of salt thickness above the workings in the Central Canada Potash Mine at Colonsay, Saskatchewan. The initial tests indicate that this new technique can measure salt thickness and that the technique possesses operational feature s which make it possible to monitor trends in salt thickness throughout the mine. The technique can be applied using existing equipment, but the tests do indicate the desirability of developing equipment with features specially suited to the mine environment.IntroductionTESTS were conducted in the Central Canada Potash Mine at Colonsay, Saskatchewan during 1974 and 1975 to determine if a new technique in electromagnetic depth sounding could provide a convenient means of measuring salt thickness above the workings. This new technique, which was described by Duckworth (1975), offers operational features which appear to be advantageous in this particular situation.The problem requires that soundings be made upward from the mine workings to the base of the second red shale. This shale forms an impermeable seal on top of the Prairie Evaporite. A knowledge of this salt thickness is of interest due to the need to avoid any possibility of the workings rising to cut the red shale. Another desirable objective is the detection of any disruptions of the red shale. Ideally, this should be done ahead of the workings in order that such areas of disruption may be avoided."

Jan 1, 1977

By A. C. Hatton

Doped SrCoO3.8 was found to be a promising material for use as a cathode component in intermediate temperature SOFCs. In this work, strontium cobaltite ceramics doped with 10 mol% to 90 mol% samarium were synthesized using the glycine nitrate process in order to study the electrical conductivity and thermal expansion at temperatures of up to 800°C. As-synthesized powders were deagglomerated, pressed and sintered at temperatures ranging from 1100-1250°C. The effect of temperature and composition on electrical conductivity and thermal expansion are presented and discussed.

Jan 1, 2005

By G. F. Raymond, W. P. Armstrong

"At the time of this study, the Valley mine was producing 23 000 tonnes of ore per day from a large, low-grade porphyry copper orebody. Sulphide mineralization, principally bornite and chalcopyrite, occurs in a stock work of quartz veins in one phase of the Guichon Creek batholith. The property was explored from 1967 to 1982, and was placed in production in 1983.Using a three-parameter lognormal approximation developed by G.F. Raymond at Similkam een and Mount Isa Mines, a geo- statistical conditional probability ore reserve was estimated prior to mining. Comparisons with blasthole kriging and milled ore for the first 17 months of production showed close agreements at all cut-offs between conditional probability estimates and mineable ore. This was not true of either kriging or polygon estimates. An important part of this work was identifying and correcting for bias in both exploration and blasthole samples.IntroductionCominco&apos;s Valley lake deposit is a large, low-grade, porphyry copper orebody in the Highland Valley of British Columbia. Total indicated plus inferred ore reserves are 700 M tonnes at ore grade of 0.47070 Cu. At the time of writing, ore milling is at a rate of 23 000 tI d through the old Bethlehem mill. Mining is in 10m horizontal benches using 9.8 m3 shovels and 90 tonne trucks. Since this paper was written, Valley and nearby Lomex have been combined into Highland Valley Copper with a combined oreproduction of about 120 000 tI d.Copper mineralization, principally bornite and chalcopyrite, is regularly distributed throughout the deposit as disseminated low-grade within a granodiorite host rock, and as higher grade veinlets within a stock work of near-vertical quartz veins generally 10 cm or less in width. It is likely that problems with sample variability and sample bias are mainly related to mineralization within quartz veining. Valley geology has been described in detail by Allen and Richardson and by Osatenko and Jones (2). The exploration sampling program and identification of diamond-drill sample bias have been discussed by Armstrong and Newman&apos;»."

Jan 1, 1988

"5.1. IntroductionThe sample preparation requirements for bulk analyses of platinum-group elements (PGE) are different from the requirements for ore microscopy and in-situ analyses. It is necessary that the initial sample collection results in as representative a sample as possible for both types of analyses. Ingamells (1980) believes, however, that sampling is always imperfect and that there is no such thing as a truly representative sample. Once collected, the usual low content and irregularly dispersed nature of the PGE require that samples for bulk analyses be made as uniform as possible, whereas in samples for ore microscopy and in-situ analyses the PGE must be concentrated. Because of the generally high specific gravity of platinum-group minerals (PGM), certain precautions must be taken, such as mixing the sample material in the bags prior to opening.5.2. Preparation forBulk Analytical MethodsThe principal factors that determine the size of the sample required for a bulk analysis are grade, heterogeneity and grainsize. Initially, the grade and sample heterogeneity can only be estimated and a sampling methodology is developed with experience. It is essential at all times, however, that the assayers have information about the source of the sample and the purpose for the analysis. Information on the grain-size, which can only be obtained through mineralogical analysis, is also very important for PGE analyses, but, unfortunately, is often ignored.5.2.1. Samples fromUnconsolidated DepositsConcentrations of PGE may occur in eluvial deposits as well as in a large variety of alluvial deposits, including those of fluvial and glaciofluvial origin. These deposits are often difficult to map and sampling is further complicated by the wide range, from sand-size to boulders, of the non-POE-bearing constituents, and by the irregular distribution and shape of the ""pay streaks"". PGE concentrations in unconsolidated deposits are largely composed of resistant Pt-Fe and Os-Ir-Ru alloys (cf. Cabri and Harris, 1975 and Raicevic and Cabri, 1976), thus making comminution to the usual-150 to -200 mesh somewhat unreliable, due to the malleability of these alloys."

Jan 1, 1979

By Pablo González, Rodolfo Espinosa, Jose-Luis Noyola, Sergio Cossio

"Minera Penmont, at La Herradura, is a joint venture between Industrias Peñoles, S.A. de C.V., and Newmont Mining Corporation. The mine is located in the northern Mexican state of Sonora. La Herradura consists of an open pit mine with two-stage crushing and heap leaching facility, the gold is recovered from the pregnant solution using the Merrill-Crowe process; production began in July 1998. La Herradura produces about 130,000 gold ounces per year, and treatment capacity is 22,000 tonnes/day. Ore mineralization occurs in a shear zone with quartz and native gold. Gold distribution is quite heterogeneous due to the coarse visible gold, in some coarser particles ranging from 100 to 600 microns.Sampling and assaying protocols where established during exploration and prior to starting up operations, based on nomographs developed from early heterogeneity tests. But, as the coarse gold problem became noticeable, it was necessary to develop new sampling protocols to have an acceptable relative standard deviation to control the fundamental error within ± 15%.An experimental program was developed and conducted on a selected ore block made of 195 blastholes; regular ore grade control procedures were applied to both sets of data to evaluate the difference in results between the protocol established prior to starting up operations (“existing”) and the new protocol (“leaching”). In the “existing” protocol, subsampling is done through riffle splitters, and coning and quartering. Fire assaying is used to estimate the gold content, on a 50 g sample. In the “leaching” protocol a 12,000 g sample was bottle rolled cyanide leached, and the leach residue was assayed on a 50 g sample using fire assaying, and a weighted average total gold content was calculated. Currently, a new alternative method is being evaluated, where sub-sampling is done using rotary splitters, and fire assay on a 50 g sample; in this “rotary sampling” protocol and for comparison purposes, gold assays were also repeated using the “leaching” protocol.Test results were compared in three groups < 0.30 g/t (below cut-off), 0.30 to 0.8 g/t, and >0.8 g/t. Overall. Results show that the protocol established prior to starting up operations underestimates the gold assays. Detailed technical results, alternative options, and their implications are discussed in the paper."

Jan 1, 2003

By S. Cossio, J. L. Noyola, R. Espinosa

"Minera Penmont’s La Herradura is a joint venture between Industrias Peñoles, S.A. de C.V. and Newmont Mining Corporation. The mine is located in the northern Mexican state of Sonora. La Herradura consists of an open pit mine with a two-stage crushing plant and heap leaching facility. Gold is recovered from the pregnant solution using the Merrill-Crowe process; production began in July 1998. La Herradura produces about 130 000 oz gold per year and its treatment capacity is approximately 22 000 t/d. Ore mineralization occurs in a shear zone with quartz and native gold. Gold distribution is quite heterogeneous due to coarse visible gold, which in some cases ranges from 100 to 600 microns.Sampling and assaying protocols were established during exploration and prior to start-up of operations, based on nomographs developed from early heterogeneity tests. However, as the coarse gold problem became noticeable, it was necessary to develop new sampling protocols to have an acceptable relative standard deviation to control the fundamental error within ± 15%.An experimental program was developed and conducted on a selected ore block consisting of 195 blastholes; regular ore grade control procedures were applied to both sets of data to evaluate the difference in results between the protocol established prior to start-up of operations (existing) and the new protocol (leaching). In the existing protocol, sub-sampling is done through riffle splitters, and coning and quartering. Fire assaying was used to estimate the gold content on a 50 g sample. In the leaching protocol, a 12 000 g sample of bottle-rolled cyanide was leached, and the leach residue was assayed on a 50 g sample using fire assaying, and a weighted average total gold content was calculated. Currently, a new alternative method is being evaluated, where sub-sampling is done using rotary splitters, and fire assay on a 50 g sample; in this rotary sampling protocol and for comparison purposes, gold assays were also repeated using the leaching protocol.Test results were compared in three groups: < 0.3 g/t (below cut-off), 0.3 to 0.8 g/t, and >0.8 g/t. Overall, results show that the protocol established prior to start-up of operations underestimates the gold assays. Detailed technical results, alternative options, and their implications are discussed in the paper."

Jan 1, 2004

By A. S. Robb

SAMPLING of an ore-body is one of the fundamentals in its exploration, development, and exploitation. It is carried out to determine the gold value per ton of an ore-shoot and the probable gold output of the refinery. Sampling also places any broken ground in one of two classes, ore or waste. The value and importance of correct sampling has been shown repeatedly in the past. On the other hand, instances could be given where those in charge of mines have not believed in sampling, and the result has been the same in every case-disaster. This has in all probability been due to assuming that good-looking, well-mineralized rock was ore. Sampling in some form might have averted this misfortune. In this essay, only the method of sampling and the estimation of ore reserves is treated. All titles, figures, and values are fictitious. None of the illustrations can be directly applied to any portion of the Hollinger mine, except Figures 1 and 2, which are included with the special permission of the Canadian Mining Journal. METHODS OF SAMPLING Hollinger Consolidated Gold Mines, Limited, has, from the very beginning of operations, carried out an extensive system of sampling, and the results of this sampling have completely governed the whole mining programme. The Hollinger discovery was made in 1909 and prospecting and exploration of &apos;the surface began at once. Four men were given jobs as samplers and they sampled thoroughly all the outcrops and all bed-rock which could be exposed to view by removing the overburden. When shaft sinking began, samples were taken at two-foot intervals. In 1912, an underground gang of six samplers was organized, and the number was increased at a rate of about two men per year as the size and extent of the workings grew. No permanent record of sampling was kept until 1919, in which year an average of 11.6 men took 28,458 samples, cutting 113,894 feet of sample. From that time until the end of 1934, the average number of samplers varied, but the total number of samples cut, and the total footage sampled, increased.

Jan 1, 1937

By P. Groleau, O. Tavchandjian, D. Marcotte

In open pit mining, each small mining unit (SMU) is selected for mill processing based on an estimate of its true grade. The estimation is usually done using analyses of cuttings from blast holes within that SMU. One common estimator used for selection is the arithmetic average of within-SMU samples. This estimator is conditionally biased. The effect of a conditional bias is to overestimate the profit really recovered from the deposit. For this reason, a conditionally unbiased estimator is preferable. Increasing the number of samples generally improves the accuracy of the estimation (and diminishes the conditional bias, if present, of most estimators). However, there exists a practical limit where an additional sample does not improve the estimation sufficiently to cover the expense of making the analysis. This limit is specific to each deposit and depends on geostatistical parameters, economic factors, and mining parameters. This study examines how the number of samples affects the recovered reserves and the resulting profit. Also, the effects on optimal profit of varying the different factors are examined. Globally, the number of samples required increases with the selectivity of the operation. For a given ore deposit, the greater the number of SMUs selected for processing, the fewer samples are required and vice-versa.

Jan 1, 1998

By John Rowson, Caitlin Brown, Kebbi Hughes, Joseph Esslifie-Dughan

The McClean Lake mill in northern Saskatchewan, Canada, is operated by Orano Canada Inc. and has been in production for the last 20 years. The tailings preparation process at the mill has been designed with decommissioning in mind, to produce tailings that are geochemically stable over the long-term within the site’s tailings management facility. Twenty years of study have contributed to a detailed understanding of geochemical and geotechnical properties of the McClean Lake tailings. Validation of the tailings properties has occurred through in-situ sampling campaigns conducted initially every year, and later every five years. Each sampling campaign has applied the same rigorous sampling procedure to provide data with useful correlations year over year. Each campaign result compares elements such as the inherent variability of the tailings, consolidation of the tailings and variations in the tailings placement methods. We will discuss lessons learned from seven sampling campaigns over 20 years and present data to show the reliable tracking of geochemical evolution of the in-situ tailings over time; providing opportunities for continuous improvements.

Jan 1, 2020

"During the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests.In the current case, a composite sample of gold ore is dedicated to a Gravity Recoverable Gold (GRG) test. The properties of interest are the head grade of gold, the size distribution of the material, and the gold assay per size class. The sample is mixed and a sub-sample is taken to measure the feed properties: the size distribution and the gold assay per size class. The remaining material of the sample is subject to the first stage of concentration using the laboratory Knelson concentrator. The concentrate is analysed in its entirety, while a sample of tailings is taken for the same analysis. The remaining part of tailings is subject to grinding to feed the second and third stages of concentration. Similar sampling is performed at each stage.The concentration performances are analysed in light of these measurements. But what is the accuracy of the measurements of the properties? Pierre Gy’s theory of sampling, associated with a heterogeneity model built using the GRG test results, will answer this question. The current paper presents, through a real example, the calculation of the errors of the measurements of size distributions and gold assays performed during the GRG test. The uncertainties of the concentration performances and liberation size estimate are then calculated and their impact on the results interpretation is analysed.INTRODUCTIONDuring the development of a mining project, samples are taken for metallurgical tests. The sample can be a composite sample made of material from a selection of various drilling products or a sample from a mining test. It can be also a sample from an existing plant in order to investigate process enhancement. This sample can represent several tonnes of material which are analysed and split for use in various tests. In order to take into account the ore variability in terms of gold deportment, it is recommended to perform variability studies (Dominy, Murphy, & Gray, 2011, Dominy, 2013) using samples representing various horizons or years of production. But for a given ore type, it can be necessary to perform many tests with different operating conditions (Brochot, 2012a). In that case, the variability of the samples is not due to the heterogeneity of distribution of the deposit, but only on the heterogeneity of constitution of the primary sample. The level of confidence associated with the estimated performance parameters is directly linked to the overall error (including sampling error) of the measurements performed during the tests."

Jan 1, 2016

By Malcolm Black

Introduction Before beginning to write this paper, I decided that I should first find suitable definitions of the words Sample and Sampling. The dictionary gives: "Sample.-A portion indicative of the whole"; and according to Baillie (1), sampling is "That process whereby a representative and comparatively small portion of material is selected from a large bulk, and preserved under such conditions as shall prevent contamination or avoidable alteration, with a view to the formation of valid conclusions regarding the suitability of the bulk for specified purposes". These comprehensive definitions are alike in substance, and indicate that unless a truly representative portion is taken, it is not a sample. Ore &apos;as mined&apos; generally varies a good deal in composition, and, in crushing, segregation takes place. Some of the minerals present, due to differences in hardness and friability, break into smaller pieces than others, and, on reaching the bin, the coarse particles roll away, leaving the fines behind. The result of this segregation is generally quite noticeable on the conveyor feeding the mill, especially when the bin is nearly empty and the crushing plant shut down. Should the sampling period synchronize with either the coarse or the fines, the sample obviously would not be representative. I agree that this is rather far fetched, but I maintain that such a condition is possible. Assuming that a representative sample may be procured from the feed conveyor, the method of cutting it down for assay has considerable influence in maintaining the original condition of the sample. The finer the material is ground after each cut, the more uniform the sample will remain. To illustrate this point, let us take a quantity of fine sand and add, say, three grains of rice to represent metallic particles. We may mix this sample by any of the known methods, then cut it into four equal portions. It is obvious that at least one of the portions will be without a rice grain. But let us grind the three grains of rice into flour and proceed as before. Now there will be a much greater chance of including some of the rice in each portion.

Jan 1, 1935

By Marcel Vallée

Abstract -Traditionally, samples collected for mineral deposit evaluation have been viewed without explicit reference to reliability, with the illusion that a true value is attainable from a few samples and verifications. For exploration, mineral deposit estimation and production quality control the following definition is proposed: "a sample is a small quantity of material relative to the geological mass it represents, collected according to a systematic procedure, of measurable reliability, from which the grade/quality of the mass which it represents may be estimated, based upon appropriate protocols. This paper will concentrate on the actual rock sampling process. Too often, sample size has been, and is still viewed as a matter of convenience, leaving out representivity considerations, despite the importance of samples on project estimation. Linear samples (chips, channels, drill), panel samples, broken rock or mining samples and very large samples are considered. Collection procedures and quality control protocols to improve the representivity of non-mechanical samples are proposed.

Jan 1, 1998

By M. D. Quinn

THE sand and gravel used for backfilling at the Hollinger mine is obtained from deposits in a low range of hills some three miles north of the mine, where the Company owns a number of claims. The material is transported to the mine by aerial tram. Shipments from these deposits to the Hollinger mine commenced in June, 1927, and since May, 1936, sand has been supplied also to the McIntyre mine. During 1942, Hollinger requirements were 1,700 tons per day, and 900 tons per day was delivered to McIntyre. For the past seven years production has averaged 900,000 tons annually, and total deliveries to the end of 1942 were 13,129,022 tons, of which 11,075,339 tons went to Hollinger and 2,053,683 tons to McIntyre. Some years ago, when the original pit was approaching exhaustion, new workings were opened on claims east and south of the tramway terminal. It soon became apparent that the sand varies considerably in character from place to place. The weight per cubic foot was found to range from 85 to 130 lb., and the water percolation rate from 2 to 50 inches per hour. As the mine requirement is a sand with percolation rate of 6 inches or better per hour, it was evident that in certain parts of the deposits the material was not suitable for use as backfill. As a consequence, it was decided to carry out a programme of systematic sampling of the claims in order to select the areas containing suitable material for back-fill and at the same time estimate the tonnage available.

Jan 1, 1944

By J. C. Gibson, C. H. Stockwell

"The San Antonio gold mine is at Bissett, Manitoba, on the north shore of Rice lake, 100 miles northeast of Winnipeg. Gold was discovered on the property in 1911, but intensive exploration was not undertaken until 1926. Milling commenced on May 1st, 1932. Total amount of ore milled from that time until the end of 1946 was 1,766,670 tons, having a value of $18,378,317.GENERAL GEOLOGYThe rocks in the vicinity of the mine are Precambrian and include three groups, namely, the Rice Lake series of volcanic and sedimentary rocks, basic and acidic intrusions, and a younger formation of sediments known as the San Antonio formation (Fig. 1). The lower part of the Rice Lake series, consisting of flows of rhyolite, trachyte, and andesite with interstratified beds of agglomerate, occupies an area extending southward from Rice lake. The lake itself and the country to both east and west of its northern end is underlain by the next succeeding beds of the series, which are chiefly tuffs, arkose, and conglomerate, but include a thin band of basalt. Northward from the lake, these are succeeded by the upper beds of the series, first a thin band of basalt and, overlying this, porphyritic andesite flows interlayered with beds of volcanic breccia or agglomerate.The Rice Lake series has been invaded on the east side of the lake by a body of basic rock ranging in composition from gabbro to diorite and quartz diorite, now much altered. This is cut by younger sills and dykes of basic rock, probably diabase, the original texture of which is largely destroyed by alteration. Numerous dykes of feldspar porphyry, quartzfeldspar porphyry, and a few of a rhyolite-like rock, occur south of the lake, but are uncommon to the north. They cut the diabase and older rocks.Extending westward from Rice lake and lying with marked angular unconformity against all of these rocks is the San Antonio formation, consisting of cross-bedded, arkosic quartzite."

Jan 1, 1954

By R. J. R. Schaller

NO. 3 winze, the sixth shaft to be sunk on the San Antonio property, is practically a duplicate of No. 3 shaft, which was the main shaft prior to the installation of the larger hoisting equipment in 1939. It is collared on the tenth, or 1,500-ft., level, and goes down vertically to the sixteenth, or 2,500-ft., level, with a loading pocket, spill pocket, and sump below this. It is 1,000 feet east of No. 3 shaft. All ore, men, and materials are handled through the latter. The winze location with reference to the rock formation is shown in Figure 1. (In plan, this section strikes N.30°E. and cuts most of the main orebodies of the mine normal to their strike.) It is collared eighty feet inside the footwall contact of the basalt and cuts through it before reaching the eleventh level. In this location there will be no ore tied up in shaft pillars, as the closest ore to the shaft is on the tenth level, and here it is eighty feet northeast of the collar. The winze headframe and hoist-room straddle the main haulage to the No. 3 shaft, on the tenth level (see Figure 2). At no time during the excavation for the headframe and hoist-room was the general routine work of this haulage held up.

Jan 1, 1941

By Z. D. Hora

Sand and gravel resources of the southern coastal region of British Columbia may be linked to various episodes of Wisconsin glaciation. During Wisconsin and probably earlier times, the Fraser Lowland and coastal areas were subjected to repeated glaciations separated by non-glacial intervals. Each major glaciation was accompanied by isostatic and eustatic changes in sea level up to 200 m or more. As a result, the Lowland was covered by the sea during much of Quaternary time. Because the Fraser Lowland is surrounded on two sides by high mountain ranges, glaciers terminated in the sea during their maximum advance. Therefore, meltwaters released during deglaciation, together wit h retreating glacier ice, could produce widespread and extensive sand and gravel deposits both along the coast and throughout the Fraser Lowland and adjacent areas.

Jan 1, 1984