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By Guillermo Diaz, Roberto Pérez, René del Villar

"Pulp-froth interface position is a key variable in column operation. In plant practice, it is commonly estimated through a system of three pressure-transducers which allows the calculation of the pulp height. An alternate method based on the measurement of the conductivity profile across the interface has been proposed and successfully tested. Both methods however, present some practical problems related to the assumptions made in the calculation of the pulp height in the former case, and to the response time and the precision of the reading in the latter case.In this paper, the use of the neural network technique for improving the estimation of the pulp-froth interface in flotation columns is discussed. The technique is used with both conductivity-based and three pressure-transducer methods. Results obtained in a 2"" laboratory column and a 12"" pilot scale column are presented. A major obstacle in applying this approach in practise is the training of the artificial neural network. This problem is analyzed here for the conductivity-based method and some solutions are proposed."

Jan 1, 1995

Everybody would agree that a good roadway leads to more efficient haulages by reducing haul times, smoother and safer operation for operator and less wear and tear on tires and equipment, thus improving availability and overall costs efficiency. There is a number of factors that come into play to achieve this especially when developing a mine. Excavations of Ramps and Headings: Operators should follow surveyors and layouts accurately while driving ramps. To maintain constant grades on ramps, which leads to better design control of water and easier grading of roadways. Dips and dives lead to needless over excavations and unnecessary cost and disposal of waste rock. When dressing a ramp some areas may require 2 to 3 feet of material to correct the dips and perfect to constant grade. You may ask yourself, is this all necessary? A small exercise is to follow a loaded haulage truck up ramp. At the first hump, grade change, notice the down shift and notice how far the truck travels to regain the up shift and his speed. The difference is remarkably noticeable when the grade is constant. All this leads to less driveline shock, less horsepower demand, better fuel efficiency and more productivity. Drill & Blast Patterns to control water for Ramp Headings: The drill pattern needs to allow for a ditch. A slight cross fall to form a ditch can easily be done with the lifters. The preferred side of the ditch is always the inside curve of the ramp as it has less tendency to erode roadbed material. On a level, the ditch is dictated by the sump location. A blasted ditch will eliminate water pounding and keep the roadbed dry. Water trapped in roadbed is the major cause of rollout and de-stability of roadbed. If the water is allowed to drain in the middle of the ramp it will cause erosion, movement and loss of fines and an increase in grading intervals.

Feb 1, 2008

By Zia Pirzada

"Time is of the essence" and "Time is money" These are powerful and true statements during a project life cycle and have far-reaching implications on the success and failure of the project Time and progress management is crucial to the project success. Project delays may increase the cost to an unacceptable level and may render the project as economically unfeasible. On the other hand, if the project is completed on time or earlier than as planned, it may generate economic benefits greater than what had been envisioned To take advantage of the financial opportunities and to improve the cash flow as well as Return On Investment (POI), project schedule can be accelerated to complete the project earlier than planned Project schedule acceleration can be achieved by using analytical tools, such as "Schedule Optimization", "Schedule Reduction", "Schedule Compression" or a combination of any of these concepts along with the "Planning for start up". Schedule optimization does not entail any extra cost, however, other acceleration methods, such as Schedule Reduction and Schedule Compression, may require extra expenditures from the owner. Based on the forecasted early start of the revenue stream, the extra expenditure could become a worthwhile venture with a very high rate of return To accelerate the schedule, all aspects of the project should be reviewed with acceleration costs calculated. All risks and opportunities should be evaluated and taken into consideration to determine if the acceleration is feasible and advisable and will provide definite financial advantages Sometimes schedule acceleration may be desired to prevent the company from paying liquidated damages. This is especially true when the project is not expected to complete on the contractual completion date and when the cost of acceleration is less than the liquidated damages that may accrue against the company.

Oct 1, 2010

By A. David MacPhail

"Highland Valley Copper is a large volume producer of copper and molybdenum concentrates. Production is by conventional truck and shovel operation combined with an extensive ore handling in-pit crushing and conveying system.Grade of the two orebodies is low at 0.4% copper and 0.007% molybdenum and this demands a production rate in excess of 260 000 tpd at a stripping ratio of 1: 1. Mining cost has to be kept at minimum levels to keep the mine profitable and thus, it is necessary to keep in the forefront: of technology. As well as the in-pit crushing system, the mine has pioneered the use of shovel weighing coupled with a state-of-the-art dispatch system.Maintenance of the equipment is carried out at the on-site mine maintenance shop with assistance from local shops for engine and wheel motor rebuilds and other large jobs such as those requiring stress relieving. Shovel and truck rebuilds are undertaken by mine crews. Both long- and short-term planning is designed and scheduled in the mine engineering section. Outside consultants are used to assist in slope design, reclamation and blasting technology."

Jan 1, 1992

By A. W. Johnston, R. E. Barrett

"The Central Patricia mine is in the greenstone belt north of lake Sc. Joseph in northwestern Ontario. It is 90 miles north of Allanwater on the Canadian National railway and 220 miles east of the Manitoba boundary. The unusual feature of the ore of this mine is that the gold does not occur in quartz but in sulphide minerals filling fractures in iron formation.AREAL GEOLOGYThe rocks of the area in which the mine occurs belong to the Early Precambrian. They consist · of andesite lavas and tuff interbedded with greywacke-like sediments and iron formation . A siliceous phase of the sediments lying north and south of the greywacke enclosing the ore-bearing iron formation in places resembles a sheared and sericitized quartz porphyry. This is shown in the legend of Fig. 1 as quartz porphyry and quartzite, but it is possible that the quartz porphyry-like phase is sediment. A northwest- striking dyke of diabase crosses the property 3,000 feet east of the shaft ( Fig. 1).IRON FORMATIONAlthough there are numerous bands of iron formation in the v1cm1ty of the mine, ore has been found to date in only one main and two lesser zones. The iron formation bands range in width from a few inches to 60 feet, and are interrupted along their strike by gaps that are parallel and rake to the east at about 65°. The iron formation is definitely banded and laminated."

Jan 1, 1954

By D. Mraz

"Under high pressure in a deep potash mine, the salt rock behaves in accordance with the concept of a generalized, perfectly plastic substance. The paper presents the evidence of this behaviour and engineering concepts f or room-and-pillar design. IntroductionThe mining and refining facilities at International Minerals &. Chemical Corporation (Canada) Limited are located near Esterhaz y at the southeastern edge of the Saskatchewan evaporites. Ore extraction began in 1962 and at the present time the annual mining capacity is in excess of eleven million tons of potash ore.A generalized geological section is shown in Figure I. The mining horizon is overlay in by 100 feet of rock salt followed by a thin bed of competent dry shale. The strata in the next 1,500 feet are generally competent and locally water bearing. The Blairmore formation contains strata of water-bearing unconsolidated sand. Below the mining horizon, rock salt is interbedded with anhydrite bands.The 8-foot mining bed is distinguished mainly by grade and clay content, as there is no definite bed boundary. The chief mineral s are halite, sylvite and, in some cases, carnallite, with up to 2 per cent disseminated clay. The ore is coarse grained, with crystals averaging one-half to three-quarters inch across.The major mining problem is related to the fact that the Dawson Bay formation, overlying the evaporites, contains areas and channels that are highly porous and permeable and are filled with unsaturated brine under high pressure. Consequently, all mining areas, with no exception, must be so designed that the overburden salt stratum remain s competently supported for the duration of the mine .This paper outlines a successful engineering method of determining the stability of the pillar s and designing a stable room -and-pillar mining system."

Jan 1, 1980

By Michel Guillot

Gaz metal arc welding is commonly used for producing large frames and assemblies. Even for light aluminum and thin wall assemblies, the GMAW technique is increasingly preferred over the GTAW technique. This is particularly true where the welding gun motion is achieved accurately with automated or robotic systems and when using pulsed or regulated metal deposition. In this study, butt joints in floor welding position are tested at speed ranging from 1.5 to 16 m/min. Attempts are made of find parameters providing good and repeatable joint quality with minimal distortion and good appearance even at high travelling speeds. Taguchi experimental plans are proposed with different parameters tested with sheet metal samples. The parameters include typical GMAW machine settings, joint preparation geometries, wire gages, gun angles, wire feeds, and more. The robot motion speed and the proximity of the part are also considered. Direct monitoring of machine welding current and voltage is achieved. Once is found the best set of parameter settings, additional tests are carried out to verify the repeatability of weld quality. Secondly, these conditions are applied for joining and testing a floor panel made of several extrusions. Weld quality is established with Vickers micro-hardness measurements, cross section geometries of the weld pool including penetration, tensile tests and metallographic observations to establish the amount of porosity and weld microstructure in the HAZ.

Jan 1, 2011

By W. R. Lindsay

Anyox, where the Hidden Creek mine of the Granby Consolidated Mining, Smelting and Power Company is located, is situated on an excellent deep-water harbour in Granby bay, at the head of Observatory inlet, about 600 miles from Vancouver and 90 miles north of Prince Rupert. Anyox is the Indian name for the little stream which empties into Granby bay, and means 'hidden creek'. The Ore-Bodies The ore is a replacement deposit and occurs at and near the contact between argillites and a later intrusive greenstone. This contact locally has a general north-and-south trend, an irregular westerly dip, and in the vicinity of the ore-bodies there has been intense folding, accompanied by faulting. The mineralizing solutions supposedly were derived from the Coast Range granite batholith, distant one to two miles to the east and north. The whole area is cut by many dykes of varying widths, which seem to have had but little part in the ore deposition.

Jan 1, 1929

"In 1989, improved milling and recoveries resulted in a record production of 7 722 200 Ib Nb2P5 at the Niobec Mine. At the beginning of 1990, proven and probable reserves stood at 11 952 000 tons grading 0.65% Nb205. This year, the world steel market has slowed and as a result, niobium consumption is down. Consequently, production at the mine dropped 14% for the second quarter.IntroductionThe Niobec Mine is located approximately nine miles northwest of Chicoutimi, Quebec, (Fig. I). After ten years of production, the Niobec Mine is the only operating niobium mine in North America and the second largest producer of niobium in the world after Brazil.The Niobec Mine is a joint venture held equally by Teck Corporation and Carnbior. Teck Corporation operates the mine while Cambior is responsible for marketing and selling the niobium pentoxide concentrate (Nb2P5).The deposit was discovered in 1964 following an airborne radiometric survey in search of uranium. However, mining of the deposit did not begin until 1976. The initial production capacity of 1500 tons per day was increased several times to the present capacity of 2450 tons . The deposit is considered as an ample source of pyrochlore concentrate for at least 15 years at the present production rate.Niobium, also known as columbium, is a greyish-white metal used primarily as an alloy in various steels and other metals. The use of niobium in alloys heightens tensile strength and improves corrosion resistance while at the same time reducing the weight of the alloy. Niobium is also used in the fabrication of steel for the aerospace, automobile, and oil and gas pipeline industries. Although substitutes for niobium exist, their use often results in diminished performance and net cost increases."

Jan 1, 1990

By Göckmann. Klau

"IntroductionCopper has been recycled ever since its discovery. Even in Graeco-Roman times recycling of this resistant, and thus valuable material was carried out as a matter of course. Just take, as an early example, the Colossus of Rhodes: after the figure collapsed during an earthquake, the bronze parts were melted down into ingots and sold.Copper is a material which can be recycled again and again because copper produced from recycling is not different from copper originating from primary materials. This is mainly due to electrolytical copper refining whereby not only the base metals but also the precious metals can be removed. In contrast, with aluminum and iron only the more electropositive elements can be removed by refining, and the resultant scrap must, therefore, be sorted mechanically into various alloys for subsequent smelting.The recycling rate for different base metals is given in Table 1. Despite this ideal prerequisite, the generally quoted recycling rate of copper of about 40070 appears rather low. However, it must not be forgotten that the recycling rate is defined as the ratio of the annually utilized quantities of copper scrap and the annual production figures (Table 2). Moreover due to the economic growth over the last 30 years the availability of copper from scrap materials is lower than its consumption because copper is principally employed in very long-life consumer durables and only returns to the recycling circuit after many years. The average time for the copper of some goods to be recycled is detailed in Figure 1."

Jan 1, 1992

By R. del Villar, A. R. Laplante

"This article presents four grinding simulation programs, written in Applesoft BASIC. The firs t two calculate residence time distributions (RT Ds) for open and closed loops mills. The third program calculates the select ion functions from the RTD, breakage function and particle size distribution (PSD) o f the feed and discharge. Two linear regression programs are also included to calculate the breakage function. These results are used in the fourth program to simulate continuous or batch grinding kinetics.The modelling approach presented is the size discrete, time continuous matrix formulation presented by Reid (1965) from concepts originally proposed by Epstein (1948). It is at the present time the most widely accepted phenomenological model of grinding kinetics and is standard textbook material (Austin et 01., 1982; Kelly and Spottiswood, 1982, p. 152). The concepts of RTDs and tracer testing originated from chemical engineering theory and practice, and are well presented in Leven spiel (2n d Ed . 1972 , Ch. 9) .Applesoft* was chosen because it is compatible with many micro computers. It is also one of the simplest and least powerful BASIC versions. Thus it can easily be adapted to other more complex BASIC versions.Open Loop Residence Time Distributions (Program RTDOPEN)As mixing, channelling, stagnation and short-circuiting all affect slurry motion in tumbling mills, transport characteristics are very complex an d cannot be derived from fundamental principles. Fortunately , as grinding follows first order kinetics, transport characteristics for the purpose of grinding simulation ca n be represented by the RTD of the slurry phase . It is normally determined using liquid tracers, as it has been demonstrated and is commonly accepted that in industrial ball mill s, the RTD of the so lid phase is particle size independent and equal to that of the liquid phase."

Jan 1, 1985

By Masaharu Moteki

At present, the Unmanned Construction System (UCS) is adapted on initial operation against the disaster. For instance, it has been used in Unzen. When the scale of the disaster is big, or the danger to a person is big, the UCS is expected as a quick and safe construction technology. The Remote Controlled UCS is introduced into construction site to repair earth-fill embankment or to remove rock, as urgent measures after the disaster outbreak. For improvement of the operability, shortening of the skill time, reduction of the fatigue, examination of the most suitable system (placement of a monitor and the joy stick) of the remote system is a main theme in the Public Works Research Institute (PWRI). In the report of this year, when the operator controls construction machine directly or he controls it using remote system (he can check the situation of site only via monitor), the degree of achievement, construction efficiency and construction precision were inspected. The remote system which is based on the system used at Unzen was developed at PWRI.

Aug 1, 2013

By T. M. Siew

"This paper begins with a brief discussion of the geology of the Newfoundland Zinc Mine area. The results of groundwater studies and pumping tests are then presented. It was decided that groundwater in the mine could best be controlled by conventional sump pumping and grouting. The system is fully described, as well as plans for improvements on the method. LocationThe Newfoundland Zinc Mine is located in the Great Northern Peninsula of Newfoundland, six miles northeast of Daniel's Harbour. The mine is situated at an elevation of approximately 350 feet above sea level, 5 miles farther inland , west of the long range of mountains which rise abruptly with elevations of over 2,000 feet above sea level.GeologyThe ore deposits occur in lower Ordovician carbonate rocks that form part of the stable St. Lawrence platform, which is mainly composed of (1) the lower Cambrian Labrador group, (2) the upper Cambrian to lower Ordovician St. George group, (3) the disconformity overlying Middle Ordovician limestones and shales of the Table Head formation and, (4) two overlying klippen composed of Cambrian and lower Ordovician rocks.The ore deposit is a Mississippi Valley type of the Tennessee variety, having proven are reserves of 5.3 million tons averaging 9.70/0 zinc from eleven ore zones which exist in an area of 5.5 square miles.Among these ore zones, the L zone is the major underground mining area, and is by far the largest of the known deposits. It has proven are reserves of 3.4 million tons with 11.5% zinc; this underground development has been inprogress since 1974.Stratigraphically, the orebody, which occurs about 300 feet below the disconformities between the Table Head and St. George formations, is situated in the upper St. George formationof lower Ordovician age.The upper St. George formation of the L zone is divided into three main units (Fig . I) : the underlying lower limestone the middle grey dolomite pseudo breccia unit and the overlying siliceous dolomite unit. In this area of the mine, the beds of the St. George formation dip gently west to northwest to 10 to 15 degrees. The orebody, which is generally strata controlled with a southwesterly plunge and which has the form of thin, narrow, but elongate, en-echelon ore bed s, is contained in grey dolomite pseudo breccia. Its dimensions vary from 50 to 900 feet in width and 8 to 120 feet in thickness, and the over-alllength exceed s 6,000 feet.The surficial deposit of the area is a till comprising a heterogeneous mixture of sand, gravel, cobbles and boulders, with an average depth of 20 feet."

Jan 1, 1980

By Jason A. McLennan

Conditional bias is an infamous problem with estimation methods including kriging. Changing estimation parameters will mitigate, but not remove, conditional bias. The conditional bias of kriging is well understood; however, there is widespread confusion in the literature and among practicing geostatisticians regarding the conditional bias of geostatistical simulation. There is no conditional bias of simulation when the simulation results are used correctly. The correct use of simulation for recoverable reserves estimation is to (1) generate multiple realizations conditional to all available data at a small scale, (2) linearly average all realizations to the chosen block size and (3) calculate the probability of each block being ore and the ore grade of each block. The ?probability of ore? and the ?ore grade? are conditionally nonbiased.

May 1, 2002

By A. E. Dyment

In formulating an explosive for any specific set of conditions, various factors must be taken into consideration. Is it to be subjected to water or moisture? .If so, it must be designed to have an inherent ability to resist water. Is it to be used in confined spaces underground, where ventilation is limited? If it is, it must possess qualities enabling it to form, upon explosion, the minimum quantity of noxious gases, such as carbon monoxide or oxides of nitrogen. Is it for use where low temperatures may possibly prevail? If so, it must be capable of resisting such temperatures without freezing. Is it for use where dust or inflammable gases may be present? If it is, then it must be so formulated as to produce, upon detonation, a flame of the lowest possible temperature and the shortest possible duration, in order to lessen the chance of ignition of such gas or dust. This is actually the essential property of a permitted explosive, and it is undoubtedly the most important characteristic of an explosive which is to be used in gassy or closed-light mines. This being the quality that distinguishes permitted explosives from other types, it is interesting to investigate the ways and means by which the low-flame-temperature characteristic is obtained . Generally speaking, such explosives are so designed as to contain comparatively small quantities of nitroglycerin and relatively large quantities of the strength-producing salt, ammonium nitrate. This ingredient does not develop as high a temperature upon explosion as does nitroglycerin, so its presence, in large measure, in place of nitroglycerin results in an explosive which has an inherent low-flame-temperature characteristic, as opposed to one which is .made up largely of nitroglycerin, which would ordinarily be in the high-flame-temperature class. Additions are also made of flame-quenching salts such as sodium chloride, ammonium chloride, and up to a certain limiting percentage of sodium nitrate. These salts, with the exception of the last, do not ordinarily take an active part in the explosive reaction, being present primarily to absorb heat liberated by the reacting ingredients.

Jan 1, 1947

By G. A. Buckland

"The development, in Ontario, of a common industry-wide program for the development of skills for employees in underground hard-rock mining is described. This program is designed to increase the productivity of individual workers by improving their skill levels, while at the same time ensuring that employees are instructed in the requisite safety and health aspects of performing various underground tasks. The program's development through a management-labour-government tripartite approach is described. How this program was coordinated with new Government Regulations on Occupational Health and Safety dealing with mandatory training of underground employees is also outlined. IntroductionThis paper will describe briefly what modular training is all about and outline why, and how, it was developed in Ontario on an industry-wide basis. Simply stated, what's been accomplished to date is an industry-wide program for developing the mining skills of underground production employees.The basic objective of this program is to improve the productivity of underground workers. It involves developing an employee's skills to improve his productivity and, because working productively involves knowing how to do a job safely, the program includes instructing an employee in the various safety and health aspects of underground work. An important and, I believe, distinguishing point about the development of this program is that it has been done with the full participation, cooperation and commitment of management, labour and government.It's of considerable interest to note that companies in Ontario who are now using this program are finding that new employees are approximately six months further advanced in productivity than was the case before its use, and in some cases the frequency of accidents has shown a reduction among those employees who have taken this program as compared to those who haven't"

Jan 1, 1980

By Gennaro Delisle

"Les Services TMG (Niobec) currently treat a niobium ore in the Chicoutimi area of Quebec. The mineral pyrochlore is present in a carbonatite deposit which assays 5% to 7% apatite.The ore is ground to minus 65 mesh and deslimed at 10 micrometres. Part of the carbonates are floated with a fatty acid emulsion and rejected to the tailings as a first step to ensure the proper conditions for the flotation of the pyrochlore concentrate. The carbonate concentrate is 65% minus 44 micrometres and is composed of dolomite, calcite, 22% apatite and a minor amount of silicates.A laboratory investigation was undertaken to determine the feasibility of extracting apatite from the carbonate concentrate. This led to the development of an economic flowsheet to produce high-grade apatite concentrate. The apatite is depressed with phosphoric acid, and the pH is adjusted at 4.8-5.0 with sulphuric acid. An additional amount of fatty acid is added to permit efficient flotation of the carbonates. 1n a second stage, the silicates left behind with the apatite concentrate can be removed by depressing the apatite with AIC3 while floating the silicates with a secondary amine.The results of the laboratory tests indicate the possibility of producing an apatite concentrate assaying 38.3% P2O5 (83.7% BPL) with a recovery of 66.2%. Pilot-plant tests undertaken at the concentrator yielded a concentrate of 34% P205 and recovery of 76%."

Jan 1, 1981

By BARRY BANNATYNE

Gypsum in Manitoba is quarried from the Jurassic Amaranth Formation a1 Gypsumville and Harcus; it has been mined near Amaranth and Silver Plains. At Gypsumville, gypsum is carbonate- free but has thin clay laminae between gypsum layers; the rock is folded in places, and some anhydrite is present. At Harcus, gypsum contains scattered dolomite, both as patches in a penemosaic pattern and as thin layers; small chalcedonic concretions also can be found. The quarry at Harcus was opened late in 1978 and currently produces about 100,000 tonnes annually. The two inactive mines near Amaranth operated from 1932 lo 1963 and from 1967 to 1970, and contain a central anhydrite layer. The mine near Silver Plains was flooded from an underlying artesian aquifer in 1975 and has not been reopened. Manitoba gypsum is used in cemem plants in Mani1oba and Saskatchewan and in wallboard plants in the three Prairie Provinces.

Jan 1, 1984

By George McIsaac

This paper discusses the formulation of a linear program with the objective of maximizing the cash flow of the long-term plan of an underground operation. A mine is split into eleven independent ore zones, each characterized by its reserves, required development and mining method. Based on practical considerations, maximum rates are set for each zone?s development and production capacity. As for the total mine plan, a minimum daily production rate is set along with a minimum feed grade to the mill. A maximum number of development metres per day is set based on the equipment and labour available. Proven and probable ore is mined preferentially over possible ore in the early years of the plan. Furthermore, the fixed cost of operating the mine is taken into consideration whenever mining activities take place. Once the linear program is solved, it can be critically reviewed, and unrealistic results can be identified. Some resource allocations constraints can then be changed in certain sectors, and new results can be analysed. What-if scenarios can also be examined, such as determining the impact of hiring a contractor to develop a given sector, or dropping an ore zone completely from the plan.

May 1, 2003

By Robert B. Parsons

"Thrashing one's way through a jungle of entangled tax rules is no easy task today, as Canada's legislators continue to complicate this country's income tax laws. At some magical point, there is presumably some balance to be struck between legislation which is equitable and unambiguous on the one hand, and at the same time is efficiently complied with and administered. It is becoming increasingly clear that the legislation is not in balance, and that there is a pressing need for some simplification of the income tax rules and regulations especially in areas of critical importance to the resource industries-even though such simplification will likely involve some sacrifice of equity and certainty.Introduction""I would wish that ... the superfluous and tedious statutes were brought into one sum together, and made more plain and short, to the intent that men might better understand them."" Edward VI, King of England 1547-1553.Regal decree notwithstanding, the legislation of most developed nations continues to become more complex, lengthy, and confusing than ever before. Canada's income tax system cannot escape the accusatory finger pointing at examples of this serious problem which plagues all of us today.Although many areas of our tax law could easily warrant some degree of simplification, for those who are involved with this country's resource sector, that horrendous, almost unreadable, part of our tax legislation which deals with resource taxation must be regarded s a prime candidate for simplification. In recent decades, but particularly in the past ten years since tax reform in 1972, budget after budget, both federal and provincial, have amended, massaged, modified, and manipulated the resource tax rules to the point where not only are taxpayers totally lost in their attempts to make some sense of the entanglement of rules, but also the draftsmen themselves acknowledge that the outer limits of complexity are being reached, and that the whole set of rules is on the verge of grinding to a groaning halt under its own weight of nonsense and frustration."

Jan 1, 1982