Mining Geology

Wednesday, April 29, 2015

The Goldstrike Mine.

Kareem Amin3:30 PMGold, Gold deposits, Mines, Mining, United States No comments

Barrick Goldstrike Mine

It is owned and operated by the world's largest gold mining company, & it is the largest gold mine in North America.

The Goldstrike Mine.

Location: Eureka County, Nevada, United States.

Products: Gold , Silver.

Ore Type: Epithermal gold deposite in carbonate or silicate sedimentary rocks.

Owner: Barrick Gold.

Ounces of gold produced in 2014 >> 902,000

Ounces of proven and probable gold reserves >> 9,614,000

Overview: The Goldstrike mine, one of the top five gold-producing mines in the world, is Barrick Gold’s largest producing mine. The mine consists of both the Betze-Post open-pit and the Meikle and Rodeo underground mines (the “Goldstrike Mine”). Barrick, which is also the biggest gold producer in the world, has operated the mine for over 20 years (since 1987). The mine is located on the Carlin Trend in north-central Nevada, USA, about 40 kilometers northwest of the city of Elko. In 2007, the Goldstrike operation produced 1.63 million ounces of gold at average total cash costs of $373 per ounce. The Goldstrike property comprises approximately 4,197 hectares of surface rights ownership and approximately 3,535 hectares of mineral rights ownership on the Carlin Trend, a prolific gold producing region of North America. The northwestsoutheast trend is an 80 km long, 8 km wide belt that contains more than 20 major gold deposits. The operation employs approximately 1,600 employees.

Geological settings & Mineralization : The Goldstrike mine complex (including the Betze-Post-Screamer and Meikle Rodeo deposits).

Betze-Post Open Pit

After Barrick took over the operation, two sulphide ore zones were identified as the Betze and Deep Post deposits in 1987. Since it entered production in 1993, the Betze-Post pit has been a truck-and-shovel operation using large electric shovels. The Betze-Post ore zones extend for 1,829 meters northwest and average 183 to 244 meters in width and 122 to 183 meters in thickness. The Post oxide orebody occurs in the siliceous siltstones, mudstones, argillites and minor limestones of the Rodeo Creek Formation. The Betze and Post oxide deposits are hosted in sedimentary rocks of Silurian to Devonian age. The mineralization of the Betze-Post pit was captured by structural traps developed by Mesozoic folding and thrust faults. Volcanic and sedimentary rocks filled ranges and basins formed by Tertiary faulting. The Tertiary volcanism initialized gold mineralization approximately 39 million years ago.

In 2007, the open pit mine produced 1,215,000 ounces of gold from 136.9 million tons mined and 10.5 million tons processed. The average grade processed is 0.136 oz/ton with a recovery rate of 85.5%. The average total cash cost was $355 per ounce. The open pit mine has proven and probable reserves totaling 12.19 million ounces from 94.9 million tons grading 0.128 oz/ton. The mine is expected to sustain the current production level for approximately 8 years, based on existing reserves. Most of the open pit mine is subject to a net smelter return of up to 4% and a net profits interest of up to 6%.

Meikle Rodeo deposits

The Meikle deposit occurs in hydrothermal and solution collapse breccias in the Bootstrap Limestone of the Roberts Mountains Formation. The gold at Goldstrike was carried into the various orebodies by hot hydrothermal fluids, and deposited with very fine pyrite and silica. Over time, the pyrite oxidized, freeing the gold and making its extraction relatively easy, as in the Post Oxide deposit. In the deeper deposits – Betze, Rodeo and Meikle – the gold is still locked up with the iron sulphide and an additional processing step (autoclaving or roasting) is required to free the gold. Two haulage drifts connect the Meikle and Rodeo orebodies.

The drifts are accessed from two shafts and by a decline at the bottom of the open pit mine. In the year ended December 31, 2007, the underground mine produced 413,186 ounces of gold at an average total cash cost of $431 per ounce. Proven and probable reserves underground are estimated at 7.42 million tons at 0.364 oz/ton, containing 2.7 million ounces. The Goldstrike’s total (open pit and underground) proven and probable mineral reserves as of December 31, 2007 are estimated at 14.9 million ounces of gold. The underground mine, which originally produced at a rate of approximately 2,000 tons of ore per day, averaged 3,562 tons per day in 2007. Based on current reserves and production capacity, the expected mine life is 9 years. The maximum royalties payable on the Meikle deposit are a 4% net smelter return and a 5% net profits interest.

Mining Processing & operations: The Goldstrike complex consist of three distinct mines: the large Betze-Post open pit mine, and the Meikle and Rodeo underground mines. The ore from all three mines is milled and leached by the cyanide process. Carlin-type gold deposits host gold mainly as microscopically fine grains. Refractory non-carbonaceous sulphide ore is treated in an autoclave followed by a carbon-in-leach (CIL) cyanidation circuit. Carbonaceous ore, also refractory, is treated with a roaster followed by a CIL circuit. The two treatment facilities treat ores from both the open pit and underground mines. Recovered gold is processed into doré on-site and shipped to outside refineries for processing into gold bullion.

In 2008 the Betze-Post open-pit mine produced 1,281,450 oz (36,328 kg) of gold and 152,886 oz (4,334.2 kg) of silver, while the Meikle-Rodeo underground operations yielded 424,687 oz (12,039.7 kg) of gold and 51,438 oz (1,458.2 kg) of silver. This was 30% of the total 5,698,000 oz (161,500 kg) output of all gold mining operations in Nevada.

Non-carbonaceous sulphide (refractory) ore is treated at an autoclave and carbon-in-leach (CIL) cyanidization circuit. Carbonaceous ore is treated at the roaster and CIL circuit, since the active carbon content in carbonaceous ore responds poorly to autoclaving. The two facilities treat ores from both the open pit and underground mines and, when combined, have a design capacity of 33,000 to 35,000 tons per day. Recovered gold is processed into doré on-site and shipped to outside refineries for processing into gold bullion. A modified pressure leach technology was successfully tested last year and it will be used to process ores that would otherwise have been treated at the roaster facility, consequently extending the life of the autoclave. The property also has a 115 megawatt natural gas-fired power plant, providing a significant portion of the operation’s power requirements off-grid.

Lac des Iles Mine

Kareem Amin1:55 PMMines Canada, Palladium, PGE deposits No comments

Lac des Iles Mine

Lac des Iles Palladium Mine

Location: Toronto, Canada.

Products: PGE Deposits.

By product: Gold. Platinum, silver, nickel, and copper.

Owner: North American Palladium Ltd.

GEOLOGICAL SETTING AND MINERALIZATION

The Property is underlain by mafic to ultramafic rocks of the Lac des Iles Intrusive Complex in the Wabigoon Subprovince of the Canadian Shield. The LDI-IC is an irregularly-shaped Neoarchean-age mafic-ultramafic intrusive body having maximum dimensions of approximately 9 km in the north-south direction and approximately 4 km in the east-west direction. The complex incorporates three discrete intrusive bodies viz.:

The North Lac des Iles Intrusion (NLDI) characterized by a series of relatively flatlying and nested ultramafic bodies with subordinate mafic rocks.

The Mine Block Intrusion (MBI), host to all of the stated Lac des Iles mineral reserves and resources (refer to Sections 14.0 and 15.0).

The South Lac des Iles Intrusion (SLDI), a predominantly mafic (gabbroic) intrusion having many similarities to the MBI in terms of rock types and textures. To date, NAP’s exploration activities have been focused on the MBI. The MBI is a small, teardrop-shaped mafic complex with maximum dimensions of 3 km by 1.5 km and having an elongation in an east-northeast direction. The MBI consists of gabbroic (noritic) rocks having highly-variable plagioclase: pyroxene proportions, textures, and structures. The MBI was emplaced into predominantly intermediate composition orthogneiss basement rocks. The MBI is intersected by a series of brittle to ductile faults and shear zones, some of which appear to control the distribution of higher-grade palladium mineralization. A major north-trending shear zone appears to have cut the western end of the MBI and is spatially associated with the development of high-grade palladium mineralization. Textural and mineralogical variability is greatest in the outer margins of the MBI, especially along the well documented western and northern margins that host most of the known palladium resources. Commonly observed textures in the noritic marginal units of the MBI include equigranular, fine- to coarse-grained (seriate textured), porphyritic, pegmatitic, and varitextured. Platinum-group element and copper-nickel sulphide mineralization in the MBI is found in a variety of structural and geological settings but in general is characterized by the presence of small amounts (e.g., typically less than 2%) of fine- to medium-grained disseminated iron-copper-nickel sulphides within broadly stratabound zones of platinum group elements (PGE) and gold enrichment.

The mineralization is commonly associated with varitextured gabbroic rocks; coarse-grained noritic rocks; and local, intensive zones of amphibolitization, chloritization and shearing. An important, distinguishing characteristic of the MBI mineralization relative to other PGE deposits is the consistently high palladium:platinum ratio, commonly averaging 10:1 or higher. Sulphide mineral assemblages are dominated by pyrite with lesser pyrrhotite, chalcopyrite, pentlandite, and millerite.

MINERAL RESERVE ESTIMATE

The mineral reserves were estimated by applying wireframe models depicting stope and pillar shapes to the underground geological block models provided by NAP. NAP aslo provided a separate, more historical geological block model for open pit evaluations, as well as RGO stockpile resource information that was used to estimate the amount of the stockpiled resource material that would be recovered during the LOM time period and accordingly be brought into the reserves. For the underground models, a mineral resource envelope was established with a 1.0 g/t palladium resource grade and a block size of 5 m by 5 m by 5 m. For the open pit block model, NAP used a 2003 block model that had a block size for pit evaluations of 15 m by 15 m by 8 m. Tetra Tech’s senior geologist reviewed and validated each of NAPs submitted block models, prior to use.

Mineral Reserves at the Cut‐off Grades

Golden Sunlight Mine

Kareem Amin8:58 AMGeology, Gold, Mines, Mining, United States 1 comment

Golden Sunlight Mine

Location: Jefferson County, Montana, United States.

Products: Gold.

Owner: Barrick Gold Corporation.

Ore Type: Breccia pipe.

Reserves: Golden Sunlight produced 86,000 ounces of gold in 2014 at all in sustaining costs of $1,181 per ounce1. Proven and probable mineral reserves as at December 31, 2014, were 127,000 ounces of gold2.

In 2015, gold production is expected to be 90,000-105,000 ounces at all-in sustaining costs of $1,000-$1,025 per ounce.

Geological setting & Mineralization

The Golden Sunlight gold-silver deposit is hosted by a breccia pipe that cuts sedimentary rocks of the Middle Proterozoic Belt Supergroup and sills of a Late Cretaceous rhyolite porphyry (Porter and Ripley, 1985; Foster, 1991a, 1991b). At depth, rhyolite porphyry forms the matrix for fragments of the pipe. Creation of the pipe appears to be related to emplacement of an underlying hypabyssal stock related to the sills. Crosscutting the breccia pipe are hydrothermally altered lamprophyre dikes that postdate the gold-silver ore; locally, these dikes may have created areas of high-grade ore in the breccia pipe near their margins. The timing of emplacement of various igneous rocks and the hydrothermal alteration related to mineralization at the deposit.

Gold and silver in the region was concentrated along northeast-striking, high-angle faults and shear zones, some of which cut the breccia pipe and along which lamprophyre dikes have been emplaced (Porter and Ripley, 1985). These structures are thought to be part of a regional, northeast-striking zone of crustal weakness that has been intermittently active from the Proterozoic to the present (Foster and Chadwick, 1990; Foster 1991a). Because some hydrothermally altered and mineralized lamprophyre dikes are preferentially emplaced along structures that cross-cut the breccia pipe, their relationship to mineralization of the breccia pipe has been ambiguous. Certainly their emplacement is later than that of the pipe, and the simplest interpretation is that lamprophyre emplacement postdates mineralization. But, because the northeast-striking shear zones, veins, and dikes contain high-grade ore in places, a mineralizing process was obviously continuing during emplacement of the lamprophyre bodies.

Geologic cross section of the Golden Sunlight breccia pipe.

Mine Life

Since its beginnings in 1982, Golden Sunlight Mine has continued to add resources to extend the life of the mine. Currently, the Montana DEQ is conducting the environmental review necessary to grant permission for mining additional resources referred to as the North Area Pit and South Area Layback, which would extend the mine life into 2016. Additional exploration is ongoing north of the Mineral Hill pit site with drilling activity in the Bonnie/Microwave area. 2013 will bring its own mix of success and challenge, so it is important that we remain intently focused on continuous improvement. As we work to deliver safe and profitable gold production, we cannot lose sight of our long-range goals—community partnership, environmental stewardship and most importantly, the safety and health of our people. I thank everyone again for the warm reception and look forward to getting to know you better in the coming months.

Safety and Health

We made great strides in improving our safety record, an achievement we celebrated in March, when we received Barrick’s Excellence Award for Best Safety Performance. As of first quarter 2013, GSM has gone five and a half years, and 2.7 million employee hours, without a lost-time incident, and over a year without a medical aid treatment incident. We still have more work to do in order to achieve our goal of zero incidents. As with most things, safety starts and ends with leadership. I expect all of our employees to be leaders when it comes to ensuring safety and continuing to send all GSM employees and contractors home safe and healthy every day.

Environment

Golden Sunlight Mine was the recipient of the prestigious Bureau of Land Management (BLM) 2012 Mineral Environmental Award for our third-party ore processing and reclamation initiatives. Golden Sunlight Mine initiated the program to assist small miners to mill outside “ores” and to assist with legacy mine materials containing reasonable concentrations of precious metals. In presenting the award, the BLM stated: “The Golden Sunlight Mine has turned liabilities into environmental and economic benefit—greatly enhancing the quality of the environment, saving taxpayer dollars, and creating local jobs.”

Bingham Canyon (Kennecott) Copper Mine

Kareem Amin3:19 PMCopper, Mines, Mining, United States 1 comment

Bingham Canyon (Kennecott) Copper Mine

It is the world's deepest man-made open pit excavation.

Bingham Canyon (Kennecott) Copper Mine

Location: Salt Lake County, Utah, United States.

Products: Copper.

Owner: Rio Tinto Group.

Ore Type : Porphyry copper deposit.

The history of the Mine:

Bingham Canyon was settled in 1848 by the Bingham brothers, Thomas and Sanford, who were ranchers with no mining experience. In 1863, soldiers stationed at Fort Douglas in Salt Lake City explored the canyon and discovered lead ore. Utah’s first mining district was created in the Bingham Canyon area that same year. In 1893, Daniel Jackling, a metallurgical engineer, and Robert Gemmell, a mining engineer, studied the deposit and recommended developing the ore body through a revolutionary open-pit mining method and processing the ore on a large, industrial scale. The miners and their families lived near Bingham Canyon in places called Highland Boy, Copper Heights, Copperfield, Carr Fork, Heaston Heights, Telegraph, Dinkeyville, Terrace Heights, Greek Camp and Frog Town. At one point, the population in the area approached 20,000 people. In 1903, the Utah Copper Company was formed to develop the mine, based on the recommendations of Mr. Jackling and Mr. Gemmell. In 1906, the first steam shovels began mining away the waste rock that covered the ore body. The ore was found in a part of the mountain that divided the main canyon.

Geology of the Mine:

Every deposit of ore in the world is unique. There are no two ore bodies that are alike. Geologic forces were at work in the Oquirrh Mountains between 260 and 320 million years ago (Late Paleozoic Period). About 30 to 40 million years ago, molten, metal-bearing rock deep within the earth’s crust began to push toward the surface and formed Bingham’s ore deposit. Volcanoes erupted above the evolving ore body. This particular ore body contains primarily copper, gold, silver and molybdenum.

Tiny grains of ore minerals, mostly copper and iron sulfides, are scattered within what is called “host rock.” Because there is far more host rock than there are minerals, it is known as a low-grade ore deposit. Because this is a low-grade deposit, a ton of ore contains only about 10.6 pounds of copper. For every ton of ore removed, about two tons of overburden must first be removed to gain access to the ore.

How big is the Bingham Canyon Mine?

Kennecott Utah Copper’s (KUC) Bingham Canyon Mine has produced more copper than any mine in history— about 18.1 million tons.

The mine is 2¾ miles across at the top and ¾ of a mile deep. You could stack two Sears Towers (now known as the Willis building), on top of each other and still not reach the top of the mine. The mine is so big it can be seen by space shuttle astronauts as they pass over the United States. By 2015, the mine will be more than 500 feet deeper than it is now. If you stretched out all the roads in the open-pit mine— some 500 miles of roadway — you’d have enough distance to reach from Salt Lake City to Denver. KUC mines about 55,000,000 tons of copper ore and 120,000,000 tons of overburden per year.

The mining process:

Bingham Canyon Mine This is where the mining process begins. Every day, Kennecott Utah Copper mines about 150,000 tons of copper ore and 330,000 tons of overburden. The ore containing copper, gold, silver and molybdenum is hauled and deposited in the in-pit crusher and sent to the Copperton Concentrator.

Copperton Concentrator From the mine, ore is transported on a five-mile conveyor and stockpiled at the Copperton Concentrator. There the ore is ground into fine particles. The smaller pieces are then combined with air, water and chemical reagents to separate the valuable minerals from the waste rock. The mineral bearing concentrate is then transported to the smelter through a pipeline.

Tailings: Are the leftover rock material that have had most of the valuable metals removed. Tailings are sent through a pipeline from the Copperton Concentrator to the tailings impoundment north of the town of Magna where they are stored.

Smelter: At the smelter, the copper concentrate is transformed into liquid copper through a flash smelting process. The copper matte is processed in the furnace to produce 98.6 percent blister copper. From there, the 720 pound copper plates, called anodes, are sent to the refinery.

Refinery: At the refinery, anodes are lowered into electrolytic cells containing a stainless steel blank and acidic solution. For 10 days, an electric current is sent between the anode and the cathode, causing the copper ions to migrate to the steel sheet. The other impurities, including gold and silver, fall into the bottom of the cell and are recovered in the Precious Metals plant. This process forms a plate of 99.99% pure copper. The copper is separated from the steel sheet and sent to market.

The Diavik Diamond Mine

Kareem Amin1:45 PMCanada, Diamond, Mines, Mining 2 comments

The Diavik Diamond Mine

Diavik Diamond Mine

Location: Lac de Gras, Northwest Territories, Canada.Products: Diamonds.

Owner: Dominion Diamond Corporation and Diavik Diamond Mines Inc.

Ore Type: The mine consists of three kimberlite pipes.

Geological notes of Diamond and The Diavik Mine:

Our knowledge of the primary sources of diamonds in the lithospheric upper mantle is mainly derived from the studies of mantle xenoliths in kimberlites and of mineral inclusions in diamonds themselves. Inclusions in diamonds preserve evidence of the physical and chemical environment at the time of diamond formation, presumed to have occurred early in Earth’s history (e.g. Richardson et al. 1984). Mantle xenoliths, in contrast, integrate a more protracted history that may have involved multiple stages of melt extraction, and thermal re-equilibration in response to short lived thermal pulses or secular cooling, and metasomatic re-enrichment. Rare diamond-bearing peridotite xenoliths provide unique opportunities to study the principal source of diamonds in the Earth’s mantle directly and to obtain information on the evolution of cratonic lithosphere, spanning the time from diamond formation to kimberlite eruption. Based on inclusion studies, peridotitic diamonds largely formed in depleted harzburgitic sources (Gurney and Switzer 1973; Gurney 1984). Evidence for changes in the composition of peridotitic subcratonic lithospheric mantle over time, involving a decreasing ratio of harzburgite to lherzolite (Griffin et al. 2003), raises the possibility that diamonds are stored in mantle rocks that are compositionally quite distinct from the environment of diamond formation. This would have important implications for diamond exploration, because indicator mineral assessment, evaluating the state of mantle lithosphere at the time of kimberlite eruption, is strongly based on chemical criteria derived from inclusion studies depicting the environment of diamond formation. One of the key questions for our study of diamondiferous peridotite xenoliths from Diavik, therefore, is verifying the extent to which the originally highly depleted signature at the time of diamond formation has been preserved or modified during subsequent metasomatic events.

Based on the composition of xenoliths and garnet xenocrysts, Griffin et al. (1999a) inferred that the mantle beneath the Lac de Gras area is chemically and thermally stratified. They suggested that an ‘‘ultradepleted’’, predominantly harzburgitic layer overlies a less depleted, predominantly lherzolitic layer with the transition being located at *145 km depth. Griffin et al. (1999a) proposed the shallower ‘‘ultradepleted’’ layer to represent Mesoarchean oceanic or sub-arc mantle lithosphere and the lower layer to be the frozen head of a Neoarchean plume derived from the lower mantle. Aulbach et al. (2007) suggested that the deeper portions of the lower layer experienced secondary re-enrichment in FeO (Aulbach et al. 2007). An alternative model for the formation of subcratonic lithospheric mantle involves stacking of highly depleted Archean oceanic lithospheric mantle beneath early continents (e.g. Schulze 1986; Helmstaedt and Schulze 1989; Bulatov et al. 1991; de Wit 1998; Stachel et al. 1998). In this model, the observed increase in fertility with depth in the central Slave craton may relate to metasomatism by infiltrating fluids/melts ascending from the asthenosphere (Stachel et al. 2003).

References

Aulbach S, Griffin WL, Pearson NJ, O’Reilly SY, Doyle BJ (2007)

Lithosphere formation in the central Slave Craton (Canada):

plume subcretion or lithosphere accretion. Contrib Mineral

Petrol 154:409–427

Bernstein S, Kelemen PB, Hanghøj K (2007) Consistent olivine Mg#

in cratonic mantle reflects Archean mantle melting to the

exhaustion of orthopyroxene. Geology 35:459–462

Bleeker W, Davis WJ (1999) The 1991–1996 NATMAP Slave

province project: introduction. Can J Earth Sci 36:1033–1042

Boyd SR, Kiflawi I, Woods GS (1994) The relationship between

infrared absorption and the A defect concentration in diamond.

Philos Mag B 69:1149–1153

Boyd SR, Kiflawi I, Woods GS (1995) Infrared absorption by the B

nitrogen aggregate in diamond. Philos Mag B 72:351–361

Griffin WL, Cousens DR, Ryan CG, Sie SH, Suter GF (1998) Ni in

chrome pyrope garnets: a new geothermometer. Contrib Mineral

Petrol 103:199–202

Kidd Creek Mine

Kareem Amin11:15 AMCanada, Copper, Mines, Mining, Zinc No comments

Kidd Creek Mine

It is the world's deepest copper/zinc mine.

Figure 1. Kidd Creek Mine

Location: Timmins, Ontario, Canada.

Products: Copper & Zinc.

Owner: Xstrata Copper.

Deposit Type: The Kidd deposit is one of the largest volcanogenic massive sulfide ore deposits in the world, and one of the world's largest base metal deposits.

Ore Geology: Kidd Creek is based on a rich, steeply dipping volcanogenic sulphide deposit located in the Archaean Abitibi greenstone belt. There are two major orebodies, with associated smaller lenses. The ore is hosted in felsic rocks of the Kidd Volcanic Complex and is cut by mafic sills and dykes. Structural deformation resulting from several phases of folding and faulting affects the distribution of sulphide lenses.

Three ore types predominate: massive, banded and bedded (MBB) ores (pyrite, sphalerite, chalcopyrite, galena and pyrrhotite); breccia ores containing fragments of the MBB ores; and stringer ores consisting of irregular chalcopyrite stringers cutting a siliceous volcaniclastic host.

Geological setting & Stratigraphic section of the mine:

The Kidd Creek Volcanic Complex is interpreted to have formed within a proto-arc geodynamic setting, with the high silica FIII rhyolites a product of crustal extension during rifting and melting of the lithosphere (Wyman et al., 1999; Prior et al., 1999). A graben interpreted to contain the Kidd VMS deposit is consistent with this geodynamic setting and a recent volcanic reconstruction of the North Rhyolite by DeWolfe et al. (2003), suggest a minimum graben width of 5 to 7 km (Gibson and Kerr, 1993; Bleeker, 1999). Fissures that controlled the eruption and emplacement of the Footwall and QP rhyolites may be graben-parallel structures (Prior, 1996).

The simplified stratigraphic column in Figure 3 provides a general overview of the Kidd Mine stratigraphy and location of massive sulfide deposits. Komatiitic flows and intrusions constitute the base of the known stratigraphic sequence and likely formed a broad, low-relief lava plain upon which the Kidd Creek rhyolitic dome and ridge complex was constructed. The minimum thickness of the komatiitic unit is estimated at 500 metres.

Figure 2. Kidd Mine ore-bodies looking east from surface to 10,200 ft

Figure 2. Kidd Mine stratigraphic column.

Figure 3. Kidd Mine stratigraphic column.

Mining operation and reserves :

The mine started production in 1966 from an open pit. The orebody is now mined at depth through three shafts as the No.1, No.2 and No.3 Mines. Phase 2 of No.3 Mine is currently being developed. Mine D will extend Kidd Creek below No 3, from a depth of 2,100m to 3,100m.

Blasthole stoping with cemented backfill is used to extract the ore underground, Kidd Creek being the world’s second-largest user of cemented backfill (after Mt Isa in Australia). Blastholes are drilled using Ingersoll Rand, Mission and Cubex drills and broken ore is hauled underground by Tamrock load-haul-dump units. The hoisting shafts are equipped with an ABB Hoist Automation System, which has significantly increased the efficiency of raising ore from depth.

At the end of 2005, Kidd Creek’s proven and probable reserves were stated as being 19Mt grading 1.8% copper, 5.5% zinc, 0.18% lead and 53g/t silver. Measured and indicated resources totalled 2.6Mt at 2.2% copper, 6.3% zinc, 0.2% lead and 48 g/t silver, with a further 11.9Mt in inferred resources at 2.7% copper, 4.8% zinc, 0.3% lead and 81g/t silver.

Note