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By Ausenco Engineering Canada

"This paper demonstrates the selection of grinding circuit technology for a number of recent projects including discussion of the key drivers and the role of energy efficiency. Decreasing head grades combined with a strong and sustained increase in operating costs has forced miners to examine increased project size, increased equipment capacity and efficiency improvements in order to reduce their unit operating costs and improve overall project economics. Comminution energy consumption, safety and capital cost considerations play a critical role in the success of projects. This paper presents some key guidelines for a successful and cost effective comminution circuit design and includes a case study on three projects, outlining the issues and the drivers which led to the ultimate circuit selection and the critical role that energy efficiency played.INTRODUCTIONComminution circuits for minerals processing are selected based on their suitability and efficiency in reducing run-of-mine ore to the desired feed size for the downstream process. The input material (ore) properties and downstream process requirements are the key determinants and there are standard approaches for each circumstance.The minerals processing industry has been a fast adaptor of efficiency improvements based on increasing capacity of equipment (e.g. trucks, crushers, mills, pumps) but less successful in adapting radically new technologies that disrupt incumbent flowsheets or processes.The installed power of grinding mills has increased linearly over the past 25 years (Meka & Lane, 2010) and pumps and classification equipment have kept pace. The autogenous grinding (AG) and semiautogenous grinding (SAG) mills displaced stage crushing as a dominant method of coarse rock breakage in many applications causing crusher manufactures to increase the capacity of cone crushers to meet the competitive demand.Examples of new comminution technology in the 20th and 21st centuries are the development and adoption of cyclone classification in the 1940s (Newtech, 2016), AG milling in the late 1950s, vertical grinding mills in the 1980s, high pressure grinding rolls (HPGRs) also in the 1980s and ultrafine milling technology in the 1990s (Meka & Lane, 2010)."

Jan 1, 2016

By M. S. Hedley

"The Lucky Jim mine is at Zincton in Slocan mmmg division; on the Kaslo-Nakusp branch of the Canadian Pacific railway. It is owned and operated by Zincton Mines; Limited; a subsidiary of Sheep Creek Gold Mines; Limited. The mine is far in the lead in the production of zinc in the Slocan. Its recorded production from concentrates and shipping ore was 102; 260; 191 pounds of zinc to the end of 1945.GENERAL GEOLOGY With the exception of acidic dykes the rocks near the Lucky Jim mine belong to the Slocan series, which is Triassic in age and consists principally of argillaceous rocks. It disconformably overlies greenstones of the Triassic Kaslo series about 3 miles to the northeast, and is cut by granitic rocks of the Nelson batholith 5 miles to the southeast.The sedimentary rocks in this area are best referred to on the whole as slates. They lie within the more fissile basal part of the Slocan series. The term 'slate belt' conveniently distinguishes this area of rocks characterized by slaty cleavage from the more massive argillites that are more characteristic of the Slocan as a whole. The contact between the slaty and massive argillites lies ½ mile southwest of the mine."

Jan 1, 1954

"The Upper Mannville unit commonly consists of interbedded marine and non-marine sands and shales, but in northwestern Alberta the unit consists of marine shales of the Spirit River Formation. A thick tongue of marine shale (Clearwater Formation) ex-tends eastward into the Athabasca area below sandy Grand Rapids beds. Correlation of Upper Mannville rocks to the southeast is difficult, but in the Cold Lake area a thick sandy depositional cycle (Mannville ""C"" of this paper) appears to be approximately correlative with the Clearwater Formation. In the Lloyd-minster region, tongues of marine sedimentary rock occur in the lower part of the Upper Mannville unit. Most of the Upper Mannville oil occurs in the Grand Rapids Formation at Wabasca, in the thick ""C"" unit and younger Mannville sands at Cold Lake, and in the Sparky and General Petroleums sands of the Lloydminster region (Figure 2).The Lower Mannville unit was deposited on an erosional surface of considerable relief that truncated the Jurassic and older strata of the Western Canada basin. Continental, probably fluviatile, sedimentation persisted over much of the Western Canada basin during deposition of the Lower Mannville unit, but an Arctic or Boreal sea lay over part of northern Alberta. At the end of the depositional episode, the sea transgressed southward and eastward (Figure 3) and re-worked the Bullhead and McMurray sands of northern Alberta into the glauconitic Bluesky and Wabiskaw sands. Topography on the sub-Cretaceous erosion-al surface had a considerable effect on the deposition of the Lower Mannville (Rudkin, 1965), and the highest hills on this surface were not completely on-lapped by Lower Mannville sediments (Figure 3). The coarser elastic material was derived both from a western Cordilleran region and from an eastern Canadian Shield region (Glaister, 1959, p. 620; Mellon, 1956)."

Jan 1, 1966

By Karl J. C. Harries

"The Table of Contents that follows is only an example and is the Table of Contents from an actual negotiated agreement. It is merely intended to show how an agreement might be set out and the nature of possible provisions. As a negotiated agreement the format was dictated by the negotiations. It is not offered as a precedent of what should be contained in a joint venture agreement (“JVA”), the “proper” sequence of Articles, or a complete listing of the contents of joint venture agreements generally. The set-up used for an agreement should be decided by the parties and be one they consider flows in a logical and workable sequence. This example sets out the “deal” first, followed by the provisions relating to how work is to be carried out and then by administrative provisions necessary to make the agreement work. If you are more comfortable with, say, having the Committee provisions at the beginning, by all means have it drafted that way -- you are going to have to live with the agreement and work under it.Notes:1. The Table of Contents provisions appear in bold print. The italicized sections are annotations, which have been provided in some cases where the heading may not clearly describe the contents. They are not intended to be comprehensive, but refer to some specific matters that are considered to be of interest or to need some clarification.2. The subject matter of many of the articles and paragraphs is discussed or commented upon in the text of the book. Some of section cross-references have been provided. Such references are only to sections where the topic is a principal subject and no attempt has been made to provide a comprehensive indexing.3. Although this particular agreement is a three-party agreement, *B* and *C*, the Owners, are required to act as a unit (see para. 1.09. – § 8.44.), making the agreement effectively a two-party agreement. The parties insisted upon having a decision-making Committee and structuring the agreement accordingly. As is explained in § 8.11., such an arrangement is not recommended and can result in problems.5. See also §§ 8.24., 8.41. and 14.13. for discussions on tables of contents, summaries, and headings."

Jan 1, 2003

By N. L. Richards

In manufacturing for the 21st century, the first company to market often leads the pack in product development and sales. In this respect, manufacturing processes play an important role in transforming “raw materials” into a product(s) for sale to a customer. Thus it can be seen that upfront modelling of a design concept, or modelling of manufacturing processes in a plant, can play an important role in effectively ensuring the overall design and manufacturing route is carried out in an expeditious manner. In the paper various scenarios are considered with respect to modelling the microstructure and/or process, in various manufacturing processes. Also considered are the effects of service condition on the manufactured product in terms of creep and fatigue.

Jan 1, 2010

By W. R. Bacon

"IntroductionTHIS IS a brief discussion of certain regional and economic aspects of the Coast Range of British Columbia. Between Portland canal and the 60th parallel of latitude, only the eastern margin of the Range is in Canada. The solely British Columbia interval extends from Portland canal to Burrard inlet. Personal observations in various parts of this area form the basis for much of this paper.Regional GeologyGranitic RocksSome of the best, most continuous exposures in the Coast Range are found at sea level. Reconnaissance study of the coastline has shown that the Range is predominantly granitic in character, but there simplicity ends, for the term 'granitic' as applied to the Coast Range covers a variety of mineralogical compositions. Actual granite is quite uncommon, occurring mainly in irregular or dyke-like masses that do not achieve batholithic dimensions. It is commonly pinkish, relatively homogeneous, and exhibits few of the deformational features that are obvious in much of this plutonic complex.Most of the granitic rocks of the Range fall well within the compositional limits of quartz diorite and granodiorite. The problem of resolving the great mass of these rocks into smaller coherent units is in general a difficult one. As noted above, granitic rock of uniform composition and texture is found in restricted areas and can be outlined without much difficulty. One such body occurs on the southern shore of Nelson island."

Jan 1, 1955

By Y. Luo

The rock breakage process in drilling is a main source of noise in roof bolting operations, especially when hard rocks are encountered. Proper control of drilling operation can provide an opportunity to improve energy efficiency of drilling and to reduce noise and heat generated from bit-rock friction. Drilling tests have been conducted in laboratory settings to confirm this noise-reduction strategy. Preliminary results show that the drilling parameters, penetration and rotational rates can be controlled to achieve in a desirable range in drilling medium hard rock. Based on the theoretical and experimental studies, rational drilling control strategy is developed for noise control while maintaining a safe and productive roof bolting operation. Applying this strategy in underground roof bolting operation, the noise exposure of roof bolter operators will be significantly reduced.

Aug 1, 2013

By M. Uszko

The paper presents the conditions for determining the selection of methods for methane drainage in Polish hard coal mines. Various factors for the evaluation of methane drainage performance are used, including the methane drainage effectiveness ratio. However, as will be discussed there are limitations to the methane drainage ratio approach resulting from the characteristics of the deposits extracted in Kompania Weglowa S.A. coal mines.

Aug 1, 2013

By V. Bazhko, V. Yahorava

The calcium sulphate waste stream of the wet phosphoric acid process, commonly called phosphogypsum (PG), contains the majority of rare earth elements (REE) initially present in the apatite feedstock. Mainly light and middle REE are present in PG and their total concentration ranges from 0.27% to 0.35% by mass. Worldwide, around 7 billion tonnes of PG have been produced to date at a current growth rate of 150-200 million tonnes per annum. In total, an estimated 21 million tonnes of REE are locked in PG waste dumps around the world. Due to the value of the REE contained in PG dumps a number of processes have been devised for their recovery. The majority of these processes applied complete or partial gypsum dissolution, but were deemed not viable due to high capital and operating costs. Mintek developed an alternative method for the recovery of REE from PG by applying Resin-in-Leach (RIL) technology. This technology was tested on PG sampled from dumps and current arisings from South African phosphoric acid production plants. The extensive testwork program included evaluation of various lixiviants and optimisation of lixiviant additions, optimisation of REE leach and adsorption conditions, batch equilibrium and kinetic adsorption tests, continuous RIL testwork and numerous variability tests. It was found that PG from different sources was highly variable, both in terms of REE recovery as well as physical properties of the material such as viscosity and filterability of the slurry. The recovery of REE varied from 15% to 80% depending on the origin of the samples. A high-level economic study indicated that at a price of >21 $/kg for mixed REE oxide product in conjunction with an overall REE recovery as low as 15% the economics of REE recovery from PG via RIL technology may already be favourable.

Jan 1, 2016

By A. D. Mufch, G. P. Mitchell

"THE HARDY MINE of Falconbridge Nickel Mines Limited is located in Lot 9, Concession 1, Levack Township, Sudbury District, Ontario, 20 miles northwest of the city of Sudbury, and a mile west of the town of Levack. The ore deposit is one of the many nickel-copper sulphide bodies found on, or near, the lower contact of the well-known Sudbury norite-micropegmatite irruptive, and is one of a family of ore deposits which occur on the northwest rim of the irruptive.The property was acquired by purchase in 1935. In the same year a magnetometer survey along the footwall contact of the norite, which is covered by about 150 feet of glacial sands and clays, first indicated the location of the orebody. Drilling from 1935 to 1942 outlined the extent of the ore. Shaft sinking was commenced in the fall of 1951, and the mine is now approaching full production at a rate of about 300,000 tons per year.There are several major differences between the geology of the Levack area and the Falcon bridge area, which lies at the opposite extremity of the irruptive, 28 miles to the east. The purpose of this paper is to describe the essential features of the geology of the Levack area as seen in the Hardy mine, and to supplement the recent papers on other properties in the Sudbury area by Davidson (1), Lochhead (2), and Yates (3).General GeologyA recent review of the regional geology and an extensive bibliography of the Sudbury area can be found in the two papers by H. C. Cooke (4, 5). Some of the recent related references are: Jas. E. Thomson (6), E. M. Abraham (7), Franc. R. Joubin (8), W. G. Q. Johnstone (9)."

Jan 1, 1949

By B. Fang

Electrochemical behavior of an X-80 pipeline steel, including frequency-sweep electrochemical-impedance spectroscopy (EIS), time-sweep EIS at a constant frequency and open-circuit potential (OCP) monitor, was investigated using four-point bending specimens subjected to a stress-corrosion cracking (SCC) test in a near-neutral pH environment, The capacitive loop became smaller with test duration, revealing an increase in the corrosion rate, The resistance obtained in the constant-frequency EIS test showed two regions, of which the region with a remarkable decrease in resistance transformed into a region of slow decrease, whereas the capacitance increased with test time indicating that iron dissolution was fast at first, and then a corrosion product or film formed and covered the surface, leading to the pitting formation.

Jan 1, 2005

By Karl J. C. Harries

"1.1. WHAT ARE AGREEMENTS AND HOW ARE THEY FORMED?In order to have an agreement, at common law, there must be an offer, acceptance of that offer, and consideration passing between the parties. In addition, the material terms (i.e. the basics or substance) of the agreement must be discernible, preferably by means of documentation. Although these concepts may appear simple and straightforward, the law relating to them is voluminous and complex. Some brief comments are worthwhile.• Offer/acceptance: Both offer and acceptance should be in writing, but they need not be. The actions, conversations, and/or correspondence of the parties may constitute either or both of them. Notwithstanding, the local law or practice of a jurisdiction will impose some specific requirements for certain types of agreements. If these requirements are not met, the agreement may be unenforceable. For example, Ontario’s Mining Act requires transfers of unpatented mining claims to be evidenced in writing and recorded.1• Consideration: Consideration is usually thought of as being money, but it can be virtually anything, even “the premises” (i.e. the mutual covenants or promises contained in the agreement itself). In addition, if one party, relying upon the offer of another, does something to his detriment, then the doing of the act can be considered to be an acceptance of the offer and, under the legal concept of “detrimental reliance”, can also be consideration. Whether or not detrimental reliance exists will depend upon the circumstances of each case.2• Material terms: The requirement that the material terms of an agreement must be discernible does not mean that all of the terms of an agreement must be documented or even have been considered, just the basic or material ones. In addition, it will be up to a judge to decide what is material – not necessarily the parties. In order to establish the material terms, a Court may look at all relevant documentation and may hear oral evidence. It will resist “writing the agreement”"

Jan 1, 2003

By R. M. Oliver

THE Falconbridge property is almost completely covered with over-burden to a depth varying from 60 to over 200 feet. This overburden consists of grave], sand, and boulder, with bands of very fine silt, and there is usually a layer of water-bearing quicksand adjoining the r:ock surface. In previous shafts sunk at Falconbridge, this water-bearing quicksand had given considerable trouble, and further difficulties were expected in sinking No. 5 shaft, due to its greater size. The method described in this paper is the one adopted in sinking this shaft, after the matter had been carefully considered. No. 5 shaft is located 2,400 feet east of the old main No. l shaft, and is sunk in norite in the hanging-wall of the ore-body, which is, however, ? practically vertical to the deepest known intersection. The greatest depths of overburden prevail on the south side, or footwall, of the ore-body, and this, together.. with the fact that the footwall is wet and more badly fractured, swayed the final decision to sink in the hanging-wall. After the shaft site had been chosen and cleared, a diamond drill was set up a few feet away and a hole bored to a depth of 405 feet to test the over-burden and character of the norite bedrock. The depth of overbudren indicated by the hole was Ill feet, with the last 10 feet water-bearing. The norite was rusted and broken up for only a few feet below bedrock. A steel sinking shield (Figure l) was assembled at the shaft location, and consisted of 5/8-inch plate, 5 feet deep, built around a frame of 6 inch by 6 inch angle-iron, and braced at the corners with the same material. Twelve-inch I-beams held the shield as rigid as possible. In order to reduce binding against pebbles to a minimum, the shield was constructed with a 1-inch batter on all sides.

Jan 1, 1938

By R. Vergunst, E. A. Devuyst, G. Robbins

"INTRODUCTIONThe Inca process for continuous cyanide removal from industrial wastewaters was patented in 1984 by G.J. Borbely, et.al. (1). The process requires SO2, air, lime and a copper catalyst. Both free and complexed cyanide are oxidized to cyanate in the pH range 8 to 10. Cyanide bound to iron is removed by precipitation as a ferrocyanide insoluble salt and other base metals are removed as hydroxides.The process was piloted in 1982 on barren bleed solution at Campbell Red Lake Mines Ltd., Ontario (2). Since 1982, the Inca SO2-air cyanide removal technology has been applied in twelve commercial installations. The process has significant advantages over other commercial processes in the completeness of cyanide removal and lower reagent requirements and costs.COMMERCIAL INSTALLATIONSBy the end of 1988 Inca will have applied its patented cyanide removal technology to twelve commercial operations. Three of these, namely Scottie Gold Mines, Dupont of Canada Expl. Baker mill and Carolin, all in British Columbia, Canada, have ceased cyanidation operations but SO2-air cyanide destruction results were good for all mills, particularly so for over two years for the Scottie mill.Removal of cyanide from CIL slurry tailings is applied at Equity Silver (9,500 tpd) and Inca's new 1,200 tpd mill at Inca/Golden Knight. Detoxification of CIP tailings is carried out by Colosseum California (3,600 tpd) and Canamax's Ketza River operation (360 tpd). Repulped tailings from Merril-Crowe flowsheets are treated at Total Erickson's Mount Skukum mill (300 tpd) and Skyline's Johnny Mountain mill (200 tpd) and barren bleed at Inco/Queenston's McBean mill (500 tpd). Lynngold's MacLellan mill (1,800 tpd) treats pond supernatant water. Plating shop cyanide effluents are decyanized at Kuntz Electroplating in Kitchener, Ontario. Many of the above commercial operations were described in some detail in previous publications (3,4). Typical installations are described in this paper. A summary of operating results is given in Table 1."

Jan 1, 1989

By M. Staite

This paper analyzed the feasibility of converting a 5kW natural gas SOFC power generator system designed to operate on natural gas to be fuelled by methanol. The analysis included laboratory methanol fuel processing experimentation, methanol reformate SOFC cell testing, and SOFC system mass and energy balance modelling. Methanol fuel processing experimentation indicated that theoretical reformate compositions can be achieved for high temperature (600-900°C) methanol steam reforming. A 6% open circuit voltage decrease and a 10% peak power current density decrease between cell operation on humidified hydrogen and methanol reformate was observed. SOFC system mass and energy balance modelling indicated that a natural gas SOFC system can be converted to operate on methanol fuel with minimal (1%) efficiency impacts, however the systems' thermal integration can be impacted.

Jan 1, 2005

By J. Lu, J. B. Wiskel, D. G. Ivey, E. Niemi, H. Henein

Simulated TMCP using a Gleeble was undertaken to evaluate the effect of the austenite to ferrite cooling rate, coiling temperatures of either 400°C or 500°C and the magnitude of plastic deformation at the coiling temperature on the hardness of a Grade 483 (X70) steel. For comparable apparent cooling rates and deformation conditions, the hardness of the samples were independent of coiling temperature The application of a minimum compressive deformation > 8% was required to increase hardness at both simulated coiling temperatures of 400°C and 500°C. An increase in hardness was also observed with increased cooling times between 800°C and 500°C (i.e., slower cooling rates).

Jan 1, 2005

By J. B. Watts

"THE Mine Engineering Department at Gaspe Copper is staffed by a chief engineer, assist-ant engineer, research engineer, chief surveyor, four instrument men, chief bonus clerk, draftsman, and a helper pool of four permanent men plus one or two students in the summer. The men are grouped according to function for organization purposes. Routine services provided by the Mine Engineering Department in-elude ail surface and underground surveying and mapping, preparation of working drawings, compilation of engineering reports, recommendations on ventilation, testing the mine air for carbon monoxide, research on mine equipment and its use, and the calculation of incentive bonus. Demand jobs from departments other than the Mine Department .are done on request. Such jobs may be in the plantsite, the Town of Murdochville, or at the shipping points at Gaspe harbour or the St. Lawrence river."

Jan 1, 1959

By S. Kaiman

This paper describes flotation test work conducted over the past several years at the Mines Branch, Ottawa, on the radioactive quartz-pebble conglomerate ores of the Elliot Lake area of Ontario. The purpose of this work has been to produce a uranium flotation concentrate for sub-sequent leaching operations. The results of earlier investigations are summarized and correlated with the results of mineralogical studies of the ores and flotation products. The results of recent pilot-plant investigations by flotation, as well as by gravity concentration followed by flotation of the gravity tailings, are given. The principal collector used for uranium flotation was a tall oil fatty acid, and the indicated total cost of all reagents ranged from 21 to 31 cents per ton of ore treated.

Jan 1, 1966

By L. M. Wang, G. P. Jiang, Y. Jiang, Liao. W. S.

ABSTRACT The authors measured porosities and permeabilities for cores from a low-permeability sandstone uranium deposit in Inner Mongolia. Features studied included fine pore structure, mineral composition, cation exchange capacity, granule appearance, and cementing features. In general, grading of the grains was relatively poor, which decreased the radii of the pore channels. The pore throat distribution was significantly heterogeneous. Pore channels ranged from small to large, but the lack of large pore channels led to low permeability. Cementation by calcite and clays, including montmorillonite, chlorite, and kaolinite, resulted in pore channel narrowing, further decreasing the permeability of the formation.

Jan 1, 2014

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