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By J. B. Kitchin

"The design of conveyor belting for use in mines poses problems to the manufacturer that are unique. The challenge to be met is that of the production of a conveyor belt which can withstand use and misuse in an environment that may differ vastly from one country to another, and even between one mine and its neighbour.The development of a product to meet such varying requirements necessitates a protracted program of trials, both in the laboratory and in the field; a new successful development, the only criterion, can be said to have been achieved only after very long-term usage under actual, deliberately chosen, arduous mining conditions.New developments in conveyor belt construction can never stop, no more than can developments in new and advanced mining techniques. A new problem is set-an answer must be found. Some of the problems are noted here, and answered where possible, in what must after all be little more than an excursion into a very comprehensive and detailed subject."

Jan 1, 1967

By Daniel L. Cluff

The Canadian mining industry needs to find viable alternatives to the conventional cemented pastefill/hydraulic methods of backfilling open stopes for underground mines located within a permafrost zone. The harsh environment and the isolated location of a mine north of 60° impose additional challenges to standard backfill methods and opportunities to the technological and operational issues related to the use of frozen fill. Underground open stoping mining methods require the placement of fill material to enable the controlled recovery of ore from secondary and tertiary stopes. The typical design of the fill material requires the specification of inert material, water and binder. The permafrost conditions provide the additional parameter of subzero temperatures for backfill design and process control. The paper presents the results of an experimental field study, using large size samples, to determine the strength capacity of frozen backfill. The experimental work was performed utilizing rockfill and tailings material with moisture content consisting of water and ice crystals. Preliminary results indicate that the mixture of rockfill, tailings and moisture, develops strength that meet the demanded requirements for open stoping. A thermal equilibrium modelling analysis is presented in the paper.

May 1, 2008

By L. H. Cole

Introduction The increasing importance of the gypsum industry in Canada is evidenced by the fact that the production has increased from 473,129 tons valued at $809,632 in 1909 to 1,205,846 tons valued at $3,622,007 in 1928, an increase of over 155 percent in quantity, and of 347 percent in value, in the 20-year period. Although the export trade in crude gypsum still forms a large proportion of the industry, it is gratifying to see that the home consumption is steadily increasing, and while the percentage of the crude gypsum mined that is manufactured into the calcined products in the country is only 16.8 per cent, its value is practically 50 per cent of the total gypsum production of the whole country. It is to be hoped that each succeeding year will see an increase in the amount manufactured in Canada, and, with the steady growth of the country and a serious endeavour to capture a part at least of the world market in gypsum products, the outlook for the industry is decidedly promising. The value of gypsum as a commercial commodity has been known from the time of the early Egyptians; in fact its value for certain purposes has been known so long chat the date of the discovery of its peculiar properties is unrecorded.

Jan 1, 1930

By Edmund C. Bovey

"AS I begin my remarks this morning, please let me say how honoured and gratified I was to receive your invitation to address you here during your deliberations in historic Quebec City. The high esteem in which your Institute is held is reflected in the respect and deference accorded to it by industry across Canada. I feel privileged to be here with you today.I would like to discuss with you some applications of natural gas in the mining industry and suggest to you, in closing, some possible avenues of future development.Natural gas first became avail-able for industrial purposes in Northern Ontario in late 1958. Acceptance of natural gas, as a source of energy by the industry of that area, has been both widespread and gratifying. The mining industry of Northern Ontario has in-creased its annual use of natural gas by approximately 35 per cent each year since 1958. We believe that this trend will continue, al-though we will probably have to accept a more modest 10 per cent annual gain as the market approaches saturation. I would like to explain how we were able to do this and where all this gas is used. Our first sales were largely a matter of price-and the savings we offered were substantial."

Jan 1, 1966

By A. C. Drost

The mining industry has been put under closer scrutiny in recent years, which has led to the adoption of a plethora of initiatives in countries around the world and by international organizations, some voluntary and others mandatory, governing economic, ethical, social and environmental practices of this industry. In order to plan appropriately, secure project financing, build value and manage risks, it is imperative to identify and understand the application of this new and evolving regime, which can be described under the general label of corporate social responsibility (?CSR?) law, and to incorporate compliance policies into the day-to-day operations of mining companies. Our paper and presentation will describe this new legal framework, which includes both ?soft? law and ?hard? law adopted at the international and domestic level that governs the actions of mining companies, particularly when operating in developing countries. While the notions of hard and soft law may seem abstract and grounded in legal theory, this paper shall demonstrate how these concepts concretely apply to companies in general, and to mining companies in particular. An analysis of the recent case law in this area as well as examples of corporate ?best practices? will illustrate the application of this body of law. As will be demonstrated through the case law, non-compliance of CSR law (both ?soft? law and ?hard? law) can lead to economic penalties, difficulties in accessing capital, loss of social licenses and even the withdrawal of permits and concessions. This confirms that now more than ever, ethics and sustainable practices in mining are fundamental to building a successful business model.

Aug 1, 2013

Mineral engineering is defined as those engineering activities that relate to the discovery, development and utilization of mineral resources. Using petroleum engineering as an example, it is shown that the breadth of the field to be studied is a major educational problem. Breadth of field is aggravated by the rapidity with which technological demands may change. At present, special short courses serve to update engineering education. Recent experience suggests an increased rate of change for the future. The fact that engineers have typically human needs and goals, and the fact that engineers respond to these in our free society, introduces a third class of problems. One approach to the solution of these problems is the unified engineering curriculum based on a core of subject mat-ter common to all engineering. Experience suggests that the unified curriculum is an effective method to minimize the importance of the first two problem areas presented, and shows a degree of success in handling some problems within the third area. Perhaps, for the good of all segments of society, it is best to have both career-oriented and unified curricula represented by educational institutions of high quality.

Jan 1, 1963

By Robin Phinney

Certain statements in this presentation may constitute "forward-looking" statements which involve known and unknown risks, uncertainties and other factors which may cause the actual results, pe1formance or achievements of the Corporation, or industry results, to be materially different from any future results, performance or achievements expressed or implied by such forward-looking statements. When used in this presentation, such statements use such words as "may", "would", "could", "will", "intend", "expect", "believe", "plan", "anticipate", "estimate" and other similar terminology. These statements reflect the Corporation's current expectations regarding future events and operating performance and speak only as of the date of this presentation. Forward-looking statements involve significant risks and uncertainties, should not be read as guarantees of future performance or results, and will not necessa1ily be accurate indications of whether or not such results will be achieved. A number of factors could cause actual results to differ materially from the results discussed in the forward looking statements including, but not limited to, the factors discussed in the Corporation's annual information form filed on March 9, 2011. Actual results could differ materially from those currently anticipated due to a number of factors and risks. These include, but are not limited to, the failure to obtain necessary regulatory approvals, including environmental approval, the failure to secure full project financing, the failure to implement the recommendations set out in the Technical Report, the failure to raise financing to implement the recommendations in the Technical Report, risks associated with the mining industry in general (e.g., operational risks in development, exploration and production; delays or changes in plans with respect to exploration or development projects or capital expenditures; the uncertainty of estimates and projections relating to production, reserves and resources, costs and expenses; and health, safety and environmental risks), decrease in potash prices and exchange rate fluctuations. Although the forward-looking statements contained in this presentation are based upon what management of the Corporation believes are reasonable assumptions, the Corporation cannot assure shareholders that actual results will be consistent with these fonvard-looking statements. These fon\?ard-looking statements are made as of the date of this presentation and are expressly qualified in their entirety by this cautionary statement. Subject to applicable securities laws, the Corporation assumes no obligation to update or revise them to reflect new events or circumstances. This presentation is a market update based on the Corporation's public disclosure and does not form a part of any offer of securities, or constitute a solicitation of any offer to purchase or subscribe for securities. Any purchase of securities in the company should be made solely on the basis of information contained in the Corporation's public record which is available on www.sedar.com .

May 1, 2013

By P. Condori, G. Rech, J. Winnett

"Palabora Mining Copper has a unique ore body composition which unlike other copper ore bodies has three main components in significant proportions; these are copper bearing ore, magnetite and dolerite. The high content of dolerite, a hard barren material, creates a high proportion of pebbles which normally are recycled back to the mill. This action increases the mill bearing pressure and power progressively until corrective actions are taken.A logical action to solve the pebbles generation would be to incorporate a pebble crusher. This in fact was done however two fundamental issues were encountered; the high content of magnetite and existence of a cyclone classification section. Due to the high content of magnetite, metal detectors have not been able to work efficiently to separate tramp metal which causes damage to the pebble crushers. The existence of cyclones in the circuit had a detrimental effect on the final product when the pebbles crusher was online producing coarse sandy material.Due to the difficulties in treating pebbles via conventional procedures and the unique Palabora ore composition and characteristics, sorting technology was investigated at laboratory and pilot scale. It was found that a combination of optical and electromagnetic sorting could efficiently separate dolerite from the copper bearing and magnetite ores.This paper reports the findings of the laboratory and pilot scale work performed and discusses the additional benefits to the circuit."

Jan 1, 2012

By W. F. Baker

Location and History God's lake is in the northeastern part of Manitoba, about 400 miles northeast of Winnipeg, or about 250 miles due north of Red lake, Ontario. The lake is quite large, having an overall length of 54 miles and a maximum width of 18 miles. There are numerous islands in the lake, the largest of these, known as Elk island, being about 15 miles long and 3 miles wide in the widest part. The accompanying map (Figure 1) shows the location of God's lake and of the mine. The God's Lake area has long been regarded as promising country for the prospector, but, due to its inaccessibility, practically no prospecting was done prior to 1927. In the years 1927-1931, inclusive, a few prospectors visited the area, but no discoveries were made. In 1932, Bob Jowsey and Archie McDonald entered the area from Island lake. They first prospected in the vicinity of Knife lake, which is immediately south of the main part of God's lake, and then moved on to the latter lake, heading for the north shore of Elk island. The first afternoon on God's Lake, when looking for a place to camp on the north shore of what is now known as Jowsey island, Jowsey discovered a quartz porphyry dyke which was cut by a number of gold-bearing bluish quartz stringers. On the strength of this discovery, he and McDonald began at once to stake the Reno group of claims. Rumours of the discovery brought in other prospectors, and other groups of claims were staked to the east, along the north shore of Elk island. A second discovery was soon made by Dan McCrea on his Gold Standard claims, three and a half miles to the east of the original discovery. Staking still continued to the east, along the north shore of Elk island, and Bob Brown and Harvey McKenzie staked the Akers group on a discovery approximately two miles east of McCrea's discovery. Through the efforts of Jowsey, the Reno, Rand, Elk, and Cona groups, belonging to the original syndicate for which Jowsey and McDonald staked, were combined with the Gold Standard, Greenstone, and Akers groups, and the Company known as God's Lake Gold Mines, Limited, was formed. Several additional groups of claims were later taken over by the Company and a considerable area of adjoining ground was staked to round-out the property.

Jan 1, 1935

By Chuck Crowell

ISO Standards ?Provide Information to Address Commercial and Safety Needs for Standardization: ?Definitions and Terminology ?Test Methods ?Performance Criteria ?Conformity Assessment Process ?Developed by Global Experts ?Promote Global Harmonization

May 1, 2013

By S. Forgeron

Presentation ? Introduction ? Canadian Underground Coal Mines ? Standardization of Geological Assessment ? Geomechanics Base-line Studies of Canadian Coal Mines ? Cape Breton Development Corporation Prince Mine ? Quinsam Coal Corporation ? 2 North and 4 South Mines ? Smoky River Coal Corporation 5B-4 Mine ? Conclusions and Baseline Comparison ? Figures

May 1, 2001

By Lawrence Devon Smith

What is a Failed Project? For mining projects, some key indicators of a ?failed? project are: ? Cost is more than it should be (particularly capital) ? Schedule ? It takes longer to build than expected ? It takes longer to ramp-up than expected ? It does not do what it is supposed to do ? Poor performance; output, product specifications; ? Low revenue ? High costs ? No one is happy about it: Management, Shareholders, Bankers ? Does a project fail if it does not meet expectations that were unrealistic and unattainable? ? Caution: Failure may not become evident until years later

May 1, 2010

By M. S. Badollet

Introduction Very little fundamental research has been done on asbestos fibre to cake maximum advantage of its properties and to determine in what commercial products it can best be utilized. For the research chemist who is associated with asbestos development work, a thorough study of mineralogical information on asbestos deposits would furnish reliable information on the rock formations and the mineral impurities closely associated with the asbestos. Furthermore, ?he must have an intimate knowledge of the uses of the fibre in various products so that he can visualize the importance of the fibre and the role it plays in industry. Some of the properties of asbestos fibres such as strength, composition, length, harshness or softness, and mineral associates are of considerable importance to the manufacturer because they are responsible for many production difficulties. Fibre Strength It has been known for some time chat asbestos filaments have considerable tensile strength. These strengths have been referred to merely as 'weak' to 'very strong'. Not until recently have numerical values been applied to the strengths of asbestos fibres. But today we can take a thin fibre filament and mount it between two holders and apply a gradually increasing load or pull until the fibre breaks. By measuring the cross sectional area of the filament and the amount of load applied, we can calculate the tensile strength of the fibre in terms of pounds per square inch. This type of test is slow and rather difficult, but the fundamental data obtained furnish important basic information that can be applied to mechanical processing equipment and to certain asbestos products.

Jan 1, 1948

By R. Glenn Madill

Western Canada is defined, for the purposes of this paper, as that part of the Dominion bounded approximately by the 95th and 141st meridians of longitude and the 49th and 80th parallels of latitude. It is comprised of Manitoba, Saskatchewan, Alberta, British Columbia, Yukon, and that portion of the Northwest Territories lying to the west of the 95th. meridian. The first magnetic observations made in Western Canada were in the interests of navigation by sea. Observations were made by Captain Middleton in Hudson bay at Churchill and York Factory in 1725, and along the Pacific coast by Captain Cook in 1778 and Captain Vancouver in 1792. The first systematic magnetic survey in Western Canada was made between 1819 and 1826 by Sir John Franklin in his widely distributed explorations. It is of interest to find that while the first magnetic declination observations made in Hudson bay and along the Pacific coast were purely in the interests of navigation, the next investigations, which were made in the Western Arctic, included measurements of inclination and force with those of declination. There was a valid reason for this more complete research into the magnetic field as the construction of declination charts depended on the position of the north magnetic pole. Halley promulgated a theory 1683 that " the globe of the Earth may be regarded as one great magnet, having four magnetic poles, two of them near each pole of the equator, and that in those parts of the world which lie near any of those magnetic poles the needle is chiefly governed thereby, the nearest pole being always predominate over the more remote" . The position of a magnetic pole may be defined as a point where the inclination is 90 degrees and the horizontal force zero. It is obvious that the position cannot be' defined by declination observations alone since, for some distance from the magnetic pole, .the horizontal force is too weak to give directive force sufficient to effect the pointing of a compass.

Jan 1, 1948

By Micheal Mayhew

"This presentation will provide information and facts on the drilling and blasting within a frozen shaft using a full face methodology. The Author will briefly discuss the history of the sinking of a frozen shaft in Saskatchewan, the challenges faced, and the solutions delivered. The case study will include a discussion describing the series of events that led to the decision to adopt a full face blasting methodology. The case study will describe key elements such as the drilling pattern, hole size and depth, explosive products and blast vibration monitoring systems. INTRODUCTION During the shaft sinking process at a project in Saskatchewan, it was recommended that a drill & blast benching method be utilized. Following an evaluation of the site, the geological conditions proved amenable to a ground freezing system that would stabilize the rock formations and prevent inflows of water into the shaft (Table 1).The shaft sinking process required that the ground surrounding the proposed shaft be frozen by drilling several near vertical freeze holes radially at a specified distance from the edge of the proposed shaft excavation. This would allow for the circulation of a chilled brine solution down the freeze holes. The circulation is achieved by means of stainless steel pipes encased within each other to provide a delivery and return conduit for the brine (Figure 1). As a result of this periphery freezing, the ground within the shaft excavation is also predominately frozen.The finished internal diameter of the shaft was 5.5 meters with varying overall excavation diameters to facilitate different liner designs used for various rock formations. For the most part, the fully unsupported/unfinished excavated diameter of the shaft varied from 6.9 meters to 8.5 meters depending on the zone excavated. The challenge was that the proposed drill and blast excavation method posed a significant risk due to the potential to damage the freeze wall and pipes during blasting. The decision was made to commence the excavation through mechanical excavation (i.e. chip and cut) methods then change to a drill and blast method utilizing a split benching design. Through this process, the team encountered five main challenges: 1. Sub-horizontal geological structures and slips that affected blasting performance and sometimes resulted in a sloping surface to the top of the bench; 2. Confined working area for the crews and equipment due to a limited work area as a result of utilizing the split (half) bench drill and blast methodology; 3. Mechanical chipping and cutting of the one-meter buffer zone to the final shaft diameter; 4. Crews working on extremely slippery uneven frozen rock and ice surfaces, which affected safety and efficiency; 5. Establishing a blast vibration monitoring system to determine if the drilling and blasting of the full shaft excavation diameter were acceptable."

Jan 1, 2019

The Shortage of Mining and Metallurgical Engineers I N many parts of the Western World attention has recently been drawn to the acute shortage of mining and metallurgical engineers produced by the universities. Naturally, the reasons for this shortage have been discussed, and various remedies for it have been proposed. In this paper, I want to examine some of them. It is now fairly generally ac-cepted among mining men that the easy attractions of modern urban life have left the career of mining in the metaphorical as well as in the literal backwoods. The industry finds it increasingly difficult to recruit adventurous and intelligent young men; for such men now seek their intellectual, if not physical, adventure in more glamorous occupations from a safe social base in suburbia. The salaries, opportunities and security offered by the mining industry do not complete effectively with the rewards offered by other industries and by commerce, taking into account the social disadvantages of a mining life. The excitement and other non-material attractions of mining

Jan 1, 1965

By V. Thangadurai

The critical problems in commercialization of the present solid oxide fuel cells (SOFCs) and useful electrical and physical properties of IT-SOFCs electrolytes are discussed briefly. The conductivity behavior of the perovskite-type and perovskite-related structure metal oxides are summarized. Perovskite-type La0.9Sr0.10ao.8Mgo.203_8 (LSGM) exhibits high ionic conductivity of 0.1 S/cm at 800 °C. In order to improve the electrical conductivity of LSGM and the In analogue of LSGM, substitutions have been made at the A-and B-sites. Substitution of trivalent La3+ by isovalent Pr3+ in LSGM and La09Sro ilno.sMgo.202.85 (LSIM), yield new mixed conductors. Among the investigated compounds in the present study, La0APro.4Sro.21no sMgo.2028 exhibits the highest total electrical conductivity of 3.2 x 10-5 S/cm at 200 °C in air with the lowest activation energy of 0.44 eV (200-700 °C). LSIM and Pr-substituted LSGM and LSIM perovskites show p-type electronic conductivity in the oxygen partial pressure range 10-5 ? 0.21 atm at 750 °C. The perovskite-type solid solution SrSn1-xFex03 exhibits compositionally driven phase transitions. For example, compound of the composition x = 0 to 0.3 crystallizes in an orthorhombic GdFeO3-like perovskite structure, where as that of x = 0.4-0.9 crystallizes in simple cubic SrTiO3-like, and that of x = 1 in orthorhombic structure. The electrical conductivity of SrSn1_xFex03 increases with the increasing Fe content and reaches a value of about 10-1 S/cm at 25 °C in air for x = 1. Compounds with low Fe content exhibit both ionic and electronic conductivity, while the higher Fe content 0.5) perovskites are electronic conductors over a wide range of oxygen partial pressure of 10-22? 0.21 atm at 750 °C.

Jan 1, 2005

By Pingchao Ke, Zhihong Liu

Fe(III)-As(V) precipitates were synthesized from the Fe(II)-As(V)-SO42--H2O system at 90°C in initial Fe(II)/As(V) molar ratios of 4.0 and 5.0, respectively. The synthesis were carried out by introducing oxygen gas into the system to oxidize Fe(II) ions into Fe (III) ions, and at the same time, adding aqueous sodium carbonate solution into the system to neutralize the acid released by the hydrolysis reactions, with the purpose of keeping the pH constant at 1.5±0.05. The precipitates obtained were characterized by XRD, chemical composition analysis, SEM, XPS, and Raman spectrum. The results indicated that the particles in the precipitates were in the morphology of irregular aggregation with their sizes in the range of about 1–4 µm. The precipitates consisted of scorodite, ferric arsenate and amorphous hydrated ferric oxide, of which amorphous hydrated ferric oxide formulated as Fe(OH)x(SO42-)y. The characteristic XPS peaks of Fe-AsO43- and Fe-O in the precipitates located at 711.8 and 713.3 eV, separately, and the existence of amorphous hydrated ferric oxide led to two series of shake off lines developed over the end of high binding energy of Fe2p XPS. The precipitates were stable in TCLP tests at pH 4.93 for 60 hours with the arsenic concentrations in the leaching solutions being 0.27 mg/L and 0.59 mg/L for the precipitates prepared in the initial Fe(II)/As(V) molar ratios of 4.0 and 5.0, respectively. The tests for the long-term stability of the precipitates were carried out by leaching them for 40 days at 25°C under various media in the pH range from 9.50 to 10.57, and the results showed that the precipitates synthesized in this study were much more stable than those by previous researchers.

Jan 1, 2017

By T. A. Chepushtanova, I. U. Motovilov, V. A. Luganov, G. D. Guseynova

"Kazakhstan has significant reserves of oxidized nickel ore with low nickel content. Processing of such ores is effective via pyrometallurgical technologies such as smelting to ferronickel or matte with consecutive extraction of metals from melting products. There are also many options for direct hydrometallurgical processing. However, they do not provide high nickel recovery.We studied extraction of nickel and cobalt by using combined technology of low-grade ore processing from the Shevchenko Kazakhstan deposit, which includes smelting to poor matte followed by hydrometallurgical processing of the matte. The nickel content in the initial ore was 0.75–0.9%. Pyrite concentrate of Sokolov-Sarybai Kazakhstan deposit containing 0.17% cobalt and 0.06% nickel had been used as a sulphidizer at smelting.As a result of the study, we were able to extract up to 98% of the nickel and up to 80% of the available cobalt. Obtained matte contained 3.1% nickel, 0.29% cobalt, 71.6% iron and 24.3% sulfur. Matte leaching was carried out by hydrochloric acid. The iron content in the pregnant solution was 170–185 g/dm3. Nickel and cobalt precipitation from the pregnant solution was carried out by hydrogen sulfide. Initial matte or cast iron was used as neutralizers during the process. Practically complete precipitation of nickel was achieved at 3–5% excess of neutralizer at 333–343°K in 4 hours; up to 95% of cobalt precipitation was achieved in 50% excess of neutralizer at 363°K in 8 hours. The purified solution contained 200–600 mg/dm3 of nickel, 80-100 mg/dm3of cobalt and 175–185 g/dm3 of iron. The purified solution allows to obtain iron oxides by high-temperature hydrolysis, and to regenerate hydrochloric acid.As a result of non-ferrous metals precipitation we obtained sulfide concentrate with concentration of Ni up to 25% and concentration of Co up to 5.5%. The technology is recommended for semi-industrial testing."

Jan 1, 2016

By Dave M. Jakelski, Gerhard W. Heinrich, Peter F. Wells, Daniel F. Suarez, Jamie B. Beauchamp

"A need for increased copper concentrate production and for less nickel contamination in that concentrate at Falconbridge's Strathcona Concentrator during 1993 required the installation of a third flotation column and improvements in the operation of the existing circuit. Innovations in wash water distributor and launder design were fundamental in achieving objectives on a new 3 meter diameter column. Minnovex plug-type spargers were tested on a 2.1 meter diameter column in order to reduce maintenance requirements. The paper details the measures taken to enhance column flotation circuit performance and the results obtained.IntroductionFalconbridge's Strathcona Mill receives 10% of the ore feed from a rich copper zone in the Strathcona mine. This ore typically grades 7% copper and 1 % nickel and, because of its high copper content, it is processed in a separate circuit ('C' circuit) which consists of conventional grinding, rougher flotation with the concentrate being treated with lime to pH 12.3 and cyanide followed by column flotation. The columns are operated with mechanical flotation scavengers and the scavenger concentrate is returned to the column feed. Testwork conducted in 1991 showed that the original flotation column (Column 2) could only produce 5.5 mtph of concentrate with less than 0.5% nickel (Figure 1).Between 1991 and spring of 1993, production was increased at times by open circuiting the scavengers. Metallurgical improvements were obtained by improving the wash water distributor of Column 2 and by wash water sprays in conventional cells (1 ). However, the scavenger concentrate assayed 0. 7 -0.8% nickel and was not acceptable for long term operation. When Copper ore production targets were significantly increased for 1993, it became clear that an additional flotation column was required. The new flowsheet employs mechanical scavenger cells on the column tails as in Column 2 circuit (Figure 2). A -parallel configuration was chosen as pulp solids fraction has been shown to be a critical variable and the second column in series would receive a lower density feed."

Jan 1, 1994