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By Ken Deter

I have some general comments on optimizing profitability based on working in heap leach operations in tropical environments. Many of my planned comments this morning have been stated earlier in the Conference. I get the opportunity to say only a few words, and follow up on some specific comments and concerns. In normal operations, stack the ore higher, where possible. The surface area of the stacked ore controls the total solution volume that can be sprayed on the pad at a specific time period. With higher lifts, solution will contact more ore particles as it percolate through the lift, and therefore the solution grade flowing through the base will be increased, whether it is freshly stacked or almost completely leached ore. This also allows more tonnage to be stacked per lift on the pad, decreasing conveyor movement and downtime. Increasing from 6 to 8 meter (20 to 26 feet) lifts have worked successfully, and some mines are using 10 meter (33 feet) lifts in 10,000-15,000 dmtpd plants. The same concept will work with smaller plants, but initial 6 meter lifts should be used until the start-up period has shown the leaching is working as planned. As the stacked ore lifts get higher, the solution flowing through the highest lift is diluted by solution retained in the lower ones. Eventually no real increase is noted from putting fresh ore in service, and gold production rate suffers. To address the dilution problem, an HDPE liner should be installed between each 2 to 4 lifts, depending on each site specific lift height, recovery, % slump in the lift, recovery rates, and grade treated, among others. The surface of the previous lift should be leveled and sloped to control the effluent draining from the planned lift, then the liner is placed, including berms and discharge pipes. The intermediate HDPE liner does not need to be completely sealed as would be the case with the base liner, and can accept some solution penetrating into the lower lifts. A one-mm (40-mil) thickness liner can be used. This intermediate liner allows the upper lift(s) higher-grade effluent to report to the pad discharge point. This will maintain higher gold solution grades going to the ponds. The slopes of the previous lifts should not be covered with HDPE in this concept, and precipitation falling on the lower lift slopes and benches can be directed to barren or surge ponds.

Jan 1, 1999

By P. Sarnoff

Gold has always been a crisis investment. For centuries gold has been considered globally the money of last resort. In time of war, inflation, financial uncertainty, political upheaval there has with few exceptions always been a flight to gold. The gold paradox simply is that even though we have gone through for the past handful of years all the kinds of. anxieties that would cause the gold price to rise, it has instead dropped drastically. Figure 1. illustrates the important factors that influenced the gold price significantly up or down before 1987. Obviously, since then, even though we have had wars, inflation, financial problems involving breaking banks and thrifts let alone collapsing financial institutions, the gold price has both in the long-term and the short-term trended downwards. Figure 2. depicts the gold price path since 1987. If the presence of time-honored and time-tested factors that should have driven the gold price up didn't do the job, then logic dictates that new factors to drive the gold price down and keep it depressed arose. And they did. But before addressing these depressants permit me to turn to the arcane art of gold price prediction and fore-casting.

Jan 1, 1992

By Richard P. Stahura

During the next five years, there will be a trend toward performing belt cleaner maintenance while the conveyor is in operation. Most mines and industrial sites that use belt conveyors have an in-house safety rule that the belt must be stopped before maintenance work can be performed on any belt-cleaning device. This is a good rule. Most cleaning devices are positioned against the belt with hardware that requires the service technician to reach or climb into the chute to change the cleaning blades. But this simple rule becomes more complicated as production demands require higher conveyor availability and provide fewer conveyor outages. In many cases, today’s conveyors are expected to be available 98% to100% of the time.

Jan 1, 1996

By M. C. Tippett

The modern era of mineral exploration in Panama began in the late 1960's, resulting in porphyry copper discoveries at Petaquilla, Rio Pito, and Cerro Colorado. In contrast, Panama's early mining history (1503 to the early 1700's) was associated with gold. A single mine, Cana, in Darien Province, produced more than one Million ounces of gold in the colonial period. Except for episodic exploration activity by British and French interests, Panama's gold potential since the 1700's has been largely ignored.

Jan 1, 1989

By L. J. Buchanan

The relationship between hydrothermal ore deposits and hot spring systems has received intensive study in recent years, particularly as a consequence of interest in the energy potential of geothermal systems. Base and precious metal deposition in surface pools and at shallow depths in modern geothermal systems has been recorded in numerous publications (1, 2, 3) Theoretical studies of hydrothermal fluid flow at depth, connected to surficial hot springs systems, have been presented by White and others (1), Cathles (2) , Henley and McNabb (3). As a result of these and additional studies, numerous hydrothermal ore deposits are thought to have originated as genetic parts of larger geothermal systems. In particular, it appears that metal precipitation is greatly enhanced in zones of boiling where volatiles and steam are escaping (4). High grade, near surface concentrations of base and precious metals, deposited as a result of partial vaporization of rising fluids, are such a common aspect of modern not spring systems that ore deposition models are becoming based on what may be called a geothermal model. In its most general terms, this model requires an anomalously high thermal gradient which acts as the driving force behind a convecting hydrothermal system. The water may be entirely meteoric or may be In part at least of other origins. The water migrates towards the higher temperature area, becomes heated, and picks up alkalies and metals by dissolving minerals along the fluid path. As water exits to the surface above the heat source, a mass balance requires the incoming hot water to rise to replace the lost water. As the water rises past the elevation where the hydrostatic pressure is insufficient to prevent boiling, then boiling will occur. Depending on the salinity and the temperature of the water, boiling can occur anywhere from great depths to near surface. Boiling results in a loss of volatiles, a pH rise in the fluid phase, cooling of the remaining fluid, a rise in oxygen fugacity, a concentration of salts in the remaining liquid, and precipitation of ore and gangue minerals.

Jan 1, 1980

By Thomas A. Simpson

Hydrogeological techniques were used to solve problems of slope stability in open-pit mines of the Eufaula bauxite district, Alabama. Geologic and hydrologic data were evaluated and used to design a system of dewatering wells to enable the operators to mine bauxite more efficiently and economically. Walls of open-pit mines in the district were subsequently stabilized by the operation of the dewatering system. Three open-pit mines, each at varying stages of the mining process, of the A. P. Green Refractories Company, were used to develop a sequential series of guidelines that indicate how to effectively remove ground water from the formations surrounding the ore bodies in the district. The use of sound engineering principles in well design, in combination with the correct interpretation of the pit hydrology provided the basis for solutions of the slope- stabilization problem aided in the economical removal of bauxite from mines of the district.

Jan 1, 1975

By James Charles McHardy

During 1980-2000, the Florida Phosphate industry will deplete its Central Florida Polk County reserves. As a result, new mines will be built in the ?so-called? Southern Florida Reserve areas. These new mines will require new mining, beneficiation and tailings disposal technologies in that the southern reserves have different characteristics than have been encountered in the Central Florida deposits furthermore, government regulations will necessitate the development of new tailings and clay disposal methods. This paper reviews these challenges for the phosphate industry and how these opportunities can be expected to effect plant design and plant operating practices.

Jan 1, 1981

By J. M. Manka

American mining companies operate many drum hoists that hoist from various depths with varying payloads. This paper will review the procedure of selecting optimum wire rope constructions for these existing hoisting installations. Selection for proposed installations along with recommended hoisting parameters will also be presented. To achieve this optimum rope performance, preventative and corrective maintenance procedures will be reviewed along with examples of rope problems and their causes.

Jan 1, 1992

By William Watson

Coal production in the United States in 2010 increased to a level of 960 Mt (1,085.3 million st), according to preliminary data from the U.S. Energy Information Administration (EIA), an increase of 1 percent, or 9.43 Mt (10.4 million st) above the 2009 level of 975 Mt (1,074.9 million st) (Table 1). In 2010, U.S. coal consumption increased in all sectors except commercial and institutional, while total coal stocks fell slightly for the year. Coal consumption in the electric power sector in 2010 was higher by 4.5 percent, while coking coal consumption increased by 37.9 percent and the other industrial sector increased by 7.1 percent. The commercial and institutional sector, which prior to 2008 had been called the ?residential and commercial? sector and is the smallest of all the coal-consuming sectors, declined by 3.1 percent in 2010. (Note: All percentage change calculations are done at the short tons level.) U.S. coal exports increased from the 2009 levels due mostly to higher demand for metallurgical coal, while coal imports decreased for a third year in a row. The increase in coal consumption for electric generation during the year was the consequence of improving domestic economic conditions further bolstered by a cold winter and warm summer in important coal-consuming regions. Preliminary data show that total generation in the electric power sector (electric utilities and independent power producers, including useful thermal output) in the U.S. increased in 2010 by 4.2 percent. Coal-based generation also increased, resulting in a 38-Mt (42-million st) increase in coal consumed in the electric power sector. Coal use in all the sectors other than the electric power sector increased by 13.9 percent to a level of 65.9 Mt (72.7 million st).

Jan 1, 2011

By Matthew S. Sanchez, Richard J. Lee, Matthew D. Zock, Drew R. Van Orden

"Current Environmental Protection Agency (EPA) risk models and asbestos fiber counting techniques for monitoring airborne exposures treat all fibers as being equivalent and ignore the effect of dimension on toxicity. While this may have been appropriate when modern analytical methods were not available, the measurement world is now fully capable of making the appropriate distinctions. The importance of width as a determinant of carcinogenicity has been recognized for nearly 30 years within the published literature. Stanton,1 in a landmark study of a suite of fibrous materials, found that durable mineral fibers with widths less than 0.25 mm and lengths longer than 8 mm were causally associated with the induction of tumors. Pott,2 in a later study, postulated a fiber toxicity model that agreed reasonably well with the Stanton findings, but extended the concept to include varying toxicity as a function of length and width. Wylie et al.3 reanalyzed samples used by Davis et al.4 and found that tumor generation was strongly and inversely correlated with fiber width. Crump5 testified increasing fiber length was correlated with disease occurrence. Lippman6 reviewed a number of studies and suggested that mesothelioma was closely associated with long, thin fibers. Berman et al.7 published a risk model, which found that disease was correlated almost exclusively with fibers longer than 40 mm and width less than 0.25 mm. Recently, Loomis et al.8 reanalyzed textile mill samples and found that aspect ratios greater than 40:1 were highly correlated with disease. Incorporation of width into risk models has been limited by the availability of data from operating asbestos plants and, in particular, the observation of an asbestos plant for which there is no observable mesothelioma. There have been only limited studies published on the dimensions of asbestos fibers, with a few serving as the primary references in other literature.9_13 A rare opportunity to collect detailed concentration and dimensional data of airborne crocidolite from an operating asbestos-cement plant using modern analytical procedures arose, providing a chance to supplement the existing literature on airborne fiber dimensions. The asbestos-cement plant is located in the eastern end of Cochabamba, Bolivia along Highway 4. Cochabamba is a relatively large city located in the Andes Mountains, approximately 250 km southeast of the capital La Paz. The city sits in a valley that runs east-west with mountains to the north and south. The crocidolite used in the products made at this facility is mined in central Bolivia, approximately 75 km northwest of Santa Cruz. The crocidolite is a fibrous magnesioriebeckite 14 (blue asbestos). Crocidolite fibers from Bolivia were the subject of prior reports suggesting the fibers are generally longer and thicker than crocidolite from Australia or South Africa.9 At the cement plant, the run-of-mine crocidolite was first pulverized using a hammer mill and then sieved on vibratory sieves to produce fibers of limited size ranges for use in the cement. The sieved crocidolite is mixed with other components, including recycled cement product, to produce a slurry that is vacuum filtered into sheet form. The sheets are then manually molded into a corrugated shape, air dried, and sawed (using circular saws) to accepted dimensions. The sawed sheets are cured in soaking pits for 28 days before being shipped to the consumer. Prior to shipping, the sheets are finished by a light hand sanding followed (at customer request) by applying one or more coats of paint. A detailed description of the cement plant and the industrial hygiene results can be found in Van Orden et al.15"

Jan 1, 2012

By David A. Campbell

There has been a long history of ironmaking on the North East coast of England centered around the River Tees. The industry developed here because of the availability of good coking coals to the North in Co. Durham, and the discovery in 1851 of ironstone in the nearby Cleveland Hills, South of the .River. Cleveland ironstone is relatively poor in quality, with an iron content not exceeding h% and high proportion of sulphur and phosphorous. The iron exists in chemical association with alumina and silica, and physical beneficiation processes involve a serious loss in iron unless the upgrading is limited, when the economics of the process become doubtful. Over the years, richer foreign ores have replaced the local ironstone, and the last operating mine was closed in 1964.

Jan 1, 1982

By John William Carlson

The Y2K or "Millenium" bug is a tiny critter, comprising no more than two digits in a date field. This bug, like its' more lethal cousins of biological and computer virus fame, has the potential to derail the economy of the U.S. and the rest of world. Whatever the reader's perception, rest assured that you will be affected by Y2K along with every person in the civilized world. How did we get to this position? It is really quite simple. The Y2K problem is a creation of computer programmers who, in an effort to conserve valuable memory in the early days of computer development, used two digits as shorthand- to define the year in date sensitive applications. Instead of typing in "1982," our experts employed "82." They believed-correctly­that the problem of limited memory would be solved by technology and assumed (nasty word) that software would be modified to take care of any problems associated with a date rollover in the year 2000. Their assumption resulted in the problem facing us today.

Jan 1, 1999

By N. L. Dorset, K. L. Heasley

Unfortunately, mining and mining accidents have gone hand-in-hand since man first started to extract ore from the ground. In the first published treatise on mining, De Re Metallica, Georgius Agricola (1556) stated that cold, water, dust, stagnant and foul air, roof falls, falls from ladders and demons all caused injury and death in the mines of his day. Although demons are no longer considered a cause of accidents in modern mining, the other factors remain with us still. The United States government started keeping track of fatalities with the establishment of the federal Bureau of Mines in 1910. Successor agencies, such as the U.S. Mine Safety and Health Administration (MSHA) continue to track fatalities today. Looking at the records, it can be seen that coal mine fatalities dropped from 2821 in 1910 to only 27 in 2004. The reduction in fatalities and injuries didn’t “just happen.” It took concentrated effort from the entire mining industry: miners, supervisors, safety officials, mining inspectors and mining researchers. But first, specific hazards must be identified before they can be corrected. In past, coal mining accidents have been analyzed by: type (roof fall, electrical, etc), mine attribute (location, seam height, etc.), and aspects of the mineworker (work experience, job classification, etc). Much of this research helped to direct the industry’s attention to where additional vigilance and safety training was needed. No doubt this directed effort has led, at least in part, to the decrease in coal mining fatalities. This paper takes a novel look at coal mining fatalities: it examines the risk of fatalities based on how long the mine has been open.

Jan 1, 2006

By Claus Becker

The new, 2.600 m long pipe under the river Elbe in Hamburg/Germany required for 2 traffic lanes, emergency lane and space for utilities a boring diameter of 14,20 m(46,6 ft). According the geology (glacial deposits consisting of clay, sand and marl, all containing big boulders) a Slurry-Shield with crusher was selected. With a minimum cover of 7 m and a maximum pressure of 5,6 bar extensive ground treatment was necessary to make the drive feasible. The machine contains a lot of new developments. The drive was finished in spring 2000 so all experiences can be reported. A special risk sharing contract avoided completely litigation.

Jan 1, 2001

By Jack Bedder, Nils Backeberg

"Native antimony metal is rare and antimony generally occurs together with gold, lead, copper and silver. There are more than 100 antimony minerals, although the sulfide mineral stibnite is the main economic mineral.Antimony enters the supply chain either as a result of mining (primary production) or recycling (secondary production). China has by far the largest antimony resources and is, as a result, the world’s center for antimony mine production. While China remains the leading primary producer, accounting for 69 percent (80.5 kt or 88,700 st) of the global 117.5 kt (129,000 st) in 2017, market consolidation and regulatory inspections across China leading to closures of facilities have caused a significant decrease in Chinese output from 115.8 kt (127,600 st) in 2015 (81 percent of global production).Tajikistan and Russia are the next largest producers of antimony after China, both ramping up production in recent years. Russia could significantly increase its supply of antimony if Polyus moves ahead with supplying 10-12 kt/a (11,000–13,200 stpy) of contained antimony from gold tailings. Australia and Bolivia are also significant mine producers outside China. The value of the different ores varies based on the metal content of the concentrates, with the most valuable gold-bearing ores sourced from Australia’s Costerfield Mine and the least valuable mercury-bearing ores sourced from the Anzob Mine in Tajikistan. On average, Bolivian and Russian ores trade at an intermediate value between those from Costerfield and Anzob. Nearly all of the rest-of-world production is exported to China, where the ores and concentrates are processed into antimony ingots and oxides.Antimony ingot production is not as widespread as is the case with antimony mine production, owing to the high levels of pollution that are associated with antimony smelting. It is for this reason that smelting has been largely confined to China and other Asian countries ,such as Vietnam and Myanmar, where environmental legislation has historically been less stringent. Tajikistan has become a growing producer of antimony ingot since 2014, coming from the commissioned metallurgical plant at the Anzob Mine.Antimony oxide production is undertaken on four continents with China being the biggest producer. There is also a considerable amount of oxide production in Europe (mainly Belgium and France), which relies on imported antimony metal feedstock, mostly from China.A new antimony project under construction by Strategic and Precious Metals Processing (SPMP) in Oman made progress in 2016 and 2017, and after producing first metal in April 2016 in test facilities, was set to be commissioned in the first quarter of 2018. Commissioning had been moved back to June 2018, with a potential ramp-up to 2-3 kt/a (2,200 to 3,300 stpy) of antimony metal by the end of 2018. SPMP is also reviewing producing antimony oxide as part of its flow sheet."

Jan 7, 2018

By Gilles Cachia, Foteini Vasilikou, Seth Pollak, Hannes Lagger

"INTRODUCTION The Shatin to Central Link (SCL) is a new rail line being constructed by the MTR Corporation for the Government of Hong Kong to cater for the growing passenger demand between the North-East New Territories and the urban areas of the city. Contract 1103, which will provide the 4 km of running tunnels between the new Hin Keng and Diamond Hill Stations, was tendered in a design-build framework and awarded to Vinci Construction Grands Projets (VCGP) in October 2012, with Arup as Vinci’s lead designer. One of the most challenging pieces of work on the contract involved the construction of 133m of SEM mined tunnel on the northern end of the project. The Northern Mined Section (NMS) is an undrained, twin-track, single bore profile, broken out through the southern pipe pile wall of the Hin Keng Station cut-and-cover box, Figure 1. The tunnel has maximum excavated dimensions of 14.5m span x 12m height, with track spacing of 6.175m. The general excavation sequence consisted of 3 stages; a 6m high top heading (73.1m2), followed by bench (27.3m2), and invert (26.7m2). A risk-based approach to the design was taken given the large variation in rock level, cover, and an active stream course above tunnel crown. Ultimately, six different temporary support types were utilized in order to optimize the construction process through continually changing ground while maintaining a safe and stable excavation. Three main support types were developed during the initial design phase, along with a “contingency” case, which utilized a partial heading excavation sequence and enhanced face support. The purpose of the contingency support type was to have a robust, engineered design available for immediate implementation should unexpected ground behavior develop, leading to the breaching of instrumentation trigger levels. This support type was never implemented on site. Drill- and-blast tunneling commenced once 6m of rock cover was verified through forward probing. A robust instrumentation and monitoring scheme provided valuable data throughout excavation and the means to carry out a geotechnical back-analysis of the ground behavior and support performance."

Jan 1, 2016

By Michael E. Zellars

The distribution of phosphate in Pliocene-Miocene deposits of the Southeastern United States was controlled by the prevailing geologic setting. For each basin a unique set of conditions in terms of relationship of land mass to shelf, depositional environment and seawater composition, and movement controlled phosphate distribution. Concentration sufficient to recognize the deposits as a resource occurred in lagoons or shallow neritic zones, with clastics and carbonates diluting the section basinward. Each deposit within a basin displays similar metallurgy and lithology, notwithstanding post-depositional alteration.

Jan 1, 1978

By E. H. Kurt

INTRODUCTION The simplest way to drill a hole into rock is to strike a steel chisel or drill bit with a hammer. Early miners used this elementary hand technique so successfully in "single jacking" and "double jacking" that the first mechanical rock-drill designers sought to duplicate it. However, in the early developments, the designers were forced to retreat to a construction known as the "piston drill," wherein the entire drilling element is tied to the piston and reciprocates with it. It took nearly 50 years to devise a method of divorcing the two elements and to achieve the original hammer principle used in hand drilling. The Mont Cenis tunnel, drilled through the French Alps in 1861, usually is considered the birthplace of the mechanical rock drill. The Hoosac tunnel in Massa¬chusetts was drilled at about the same time, and the success of these two ventures paved the way for innova¬tions that produced the Burleigh, Ingersoll, Sergeant, and Waugh piston drills between 1870 and the turn of the century. In 1897, George Leyner of Colorado introduced what has been considered the most significant development in rock-drill history. He devised the hollow drill steel for water flushing; when combined with his free-piston hammer drill, this became the first lightweight and dust¬free underground machine. In addition, Leyner's drills introduced improvements such as automatic rifle-bar rotation of the drill steel and chuck, automatic lubrica¬tion, and an enclosed throttle control. During the 1920s and 1930s, automatic feeds, centralizers, sliding cones, and the automatic water back head were developed, laying the groundwork for all pneumatic underground drills currently in use. Since these pioneering efforts, rock-drill development has been concerned primarily with refining the designs and improving the metallurgy to make faster, lighter, and more dependable machines. Fig. 1 illustrates the progress in drilling speed during the first 125 years of rock-drill development; that progress is a credit to the persistence and inventiveness of the designers in the rock-drilling industry. ROCK-DRILL CLASSIFICATIONS To meet the variety of conditions encountered in rock drilling, several distinct types of drills have been de¬veloped. In general, rock drills may be classified as either hand-held or mounted, with the hand-held ma¬chines including the jackhammer or sinker, the jackdrill or jackleg, and the stoper. The mounted drills are com¬monly known as "drifters." Table 1 shows that each type of drill is available in several sizes from different manufacturers. Fig. 2 illustrates a typical rock drill, showing the principal components. The jackhammer or sinker, shown in Fig. 3, is used primarily for general mine utility work such as drilling anchor holes (short vertical holes to bolt or anchor machinery), pin holes (short, usually horizontal holes to fasten sheaves, etc. to side walls), popholes (for blasting large boulders), and similar applications. They also are used for shaft sinking. Jackhammers are classified ac¬cording to weight, and they range from 7 to 30 kg (15 to 65 lb). The rock drill originally known as a jackleg was made by clamping a pneumatic cylinder or leg to a jack¬hammer, both to support the weight of the machine and to feed the tool forward in horizontal or uphole work. The more modern jackdrill refined this concept to make the hinged pivot for the leg integral with the drill cylinder and to group all drill and leg controls in the drill back head for convenience. Fig. 4 illustrates a typical jackdrill. Jackdrills are classified according to cylinder bore size, ranging from 60 to 83 mm (2.375 to 3.25 in.). Because of their light weight and versatility, jack drills are very effective in small drifts, small tunnel head¬ings, and stoping. The larger machines are applied to hardrock formations and in applications where drilling speed is a primary consideration. In soft formations or

Jan 1, 1982

By Mary Korpi

So now you ask, Where are the transcripts? The well-organized co-chairs, Harry and Mary, did their job. Doug Halbe was active in the audience encouraging people to speak up and keeping everything moving along. So where are they? Were the comments so provocative that they could not be written? Was the profanity so bad (even for miners!) that it couldn't be repeated? It appears that at the first session of the Plant Operators' Symposium a glitch occurred with the recording equipment. Thanks go to everyone who did comment during the dis- cussion period. The People I session had a lot of lively conversation and we are sorry that it will not be printed. However, there is now another reason to hold the plant operators' sessions on a regular basis! Another People session can and will be held in the future.

Jan 1, 1998

The Iron Ore Company of Canada (IOC) is the largest manufacturer of iron ore pellets in Canada and its customer base covers North American, European and Asian steel producers. The company operates a mine, concentrator and a pelletizing plant in Labrador City, Newfoundland and Labrador, as well as port facilities located in Sept-Iles, Quebec. It also operates a 418-km (260-mile) railroad that links the mine to the port. IOC has approximately 1,900 employees. Its shareholders are Mitsubishi Corp. (26.18 percent), Labrador Iron Ore Royalty Income Fund (15.1 percent) and the international mining group Rio Tinto, which is its major shareholder (58.72 percent) and operator, with activities in more than 40 countries throughout the world. The IOC was incorporated in 1949 and by 1954 it had completed the Quebec North Shore and Labrador (QNS&L) rail line. IOC began mining in Schefferville, Quebec by 1954 and closed those operations down in 1982. In 1962, IOC commissioned the present day Carol Project consisting of mining, concentration and pelletizing facilities in Labrador City, Newfoundland. In 2004, IOC shipped its one-billionth tonne of ore on the QNS&L Railway. In 2005, IOC celebrated 50 years of mining history. The company expressed an interest in reducing the amount of oversize material (>1 m x 1 m x 1 m or 3.2 ft x 3.2 ft x 3.2 ft) being produced and its subsequent downstream effects, including in-pit sorting and reduction, damage to mobile equipment and significant delays in the loading pockets and the primary crushers. To achieve this goal, an oversize reduction project was undertaken by the mine that, to date, has significantly improved upon baseline measures. One key approach used to reduce the amount of oversize was the implementation of thicker emulsion. The introduction of a thicker emulsion provided more resistance to the forces created by dynamic water and reduced the infiltration of the emulsion into the cracks and fissures of the rockmass, resulting in reduced amounts of oversize and more consistent fragmentation throughout the muckpiles. Additionally, a significant reduction in nitrates leached into the mine water discharge has been realized. To determine the effectiveness of the oversize reduction project, IOC used a first-of-kind technology to assess fragmentation presented to the shovel at the digging face. A digital vision system (DVS) was installed on one of the shovels to capture images that were stamped with GPS locations. A large population of digital images were analyzed to produce a robust fragmentation distribution baseline that was used as one of the mine key performance indicators (KPI). Changes to blasting practice were subsequently measured against the baseline KPI to assess effectiveness.

Jan 1, 2011