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July 8, 2015
With 53 different minerals at its disposal, Turkey is one of the most mineral rich countries earth. But Turkish miners also face one of the world’s most challenging mining environments.
Over the past 10 years, Turkey’s mineral production has increased by some 300 percent and the country’-s mining industry continues to grow. In 2011, mining exports reached USD 2 billion with chromite, copper, natural borate and zinc taking the lion’s share.
To keep up the momentum and meet their ever increasing productivity targets, mining contractors are increasingly relying on Atlas Copco equipment.
The copper mines at Murgul, in the northeast, are a typical example. Privatized in 2006, these are now operated by Eti Bakir, a subsidiary of Cengiz Holding. In addition to its open pit, Eti Bakir also has an underground operation about 5 km away, with both mines now using Atlas Copco equipment.
In the open pit, a fleet of seven Atlas Copco drill rigs are used for production drilling and two for secondary blasting and other ancillary work.
In the Aralik underground mine, Eti Bakir operates a Boomer 282 two-boom development rig, a Simba 1254 production rig, two Scooptram ST1030 loaders and two MT2010 mine trucks . Added to this is a specially adapted Scooptram ST-3.5 with a dozer blade designed for placing backfill in worked out stopes.
First to arrive was a ROC L8 (renamed FlexiROC D60) in 2007. “Since then,” says Bahadir Egener, Atlas Copco’s Business Line Manager in Turkey, “Eti Bakir has added another four —FlexiROC D60 rigs giving them sufficient drilling capacity as well as the luxury of always having a machine in reserve so that they can keep their maintenance on schedule.
“The ore here is very abrasive, while the climate is a real challenge for all of our equipment,” says Hasan Kesimal, Mechanical Manager. “Summers are hot and dry, with temperatures of up to 35° or 38°C, and the dust is a problem for the machines. Winter is something else. It’s cold and wet, down to minus 15°C, and the mud is abrasive and really hard on the rigs’ undercarriage.”
To maintain its production schedule, the open pit has to move 10 000 t of ore per day plus another 30–35 000 t of waste. The target for 2012 is about 10 Mt of waste and 3 Mt of ore, with an output of 100 000 t of copper concentrates. The waste in the Murgul open pit is typically tufa, relatively soft volcanic rock, while the ore is in hard, high-silica dacite.
Mustafa Mert has been operating a FlexiROC D60 for the past six years. He says: “In ore, a 12 meter hole takes around 20 minutes to drill and in waste about ten minutes or more if there’s a mixture of rock types in the hole.”
The FlexiROC D60 drills a 165 mm hole, using a COP 64 Gold DTH hammer with a convex spherical bit and 114 mm rods. The benches are 10 m high and are drilled with 2 m of sub-drilling. Typical productivity is 15 holes per 10-hour shift, although some of the drillers can complete up to 25 holes if the conditions are good.
Eti Bakir has found that a 4×4 m spacing is suitable for ore and 5×5 m for waste, although natural fracturing in the dacite means that oversize boulders are common and require secondary breaking.
The mine uses a ROC D7 rig (renamed FlexiROC T35) equipped with a COP 1840 HE (High Energy) tophammer rock drill to drill 89 mm holes for secondary blasting of the large boulders, while the smaller boulders are taken care of by two Atlas Copco HB2000 breakers.
According to Mine Manager Ferhat Ekren, ore production is 140 000 t/y, with the ore from the open pit and underground mine treated in separate concentrator plants. The high and low grade ores from the underground mine are also stored separately on the surface before treatment.
The Boomer 282 is used for mine development which involves the excavation of 5×5 m drifts. Using 3.5 m rods and 45 mm ballistic insert bits, operators achieve a 3 m advance per round using a burn cut pattern with around 60 holes per face. Atlas Copco Swellex bolts as well as split set bolts provide immediate roof support, with fibre-reinforced shotcrete sprayed throughout.
Stope drilling with the Simba uses holes 15 m long and 89 mm in diameter, mainly vertically but also inclined at the orebody edges to follow the ore/waste boundary.
The Scooptram LHDs load the mine trucks for hauling ore to the surface and the stopes are then backfilled using cement-bonded waste rock. The LHDs are also involved in placing the fill, as is the dozer-equipped Scoopram ST-3.5 which can pack the material tighter into place.
On the other side of the country, high on the Anatolian plateau, Canadian company Eldorado Gold Corp has successfully commissioned its Kisladag gold mine.
Operated through Eldorado’s subsidiary, Tüprag Metal Madencilik Sanayi ve Ticaret, the mine opened in 2006 and is now Turkey’s No.1 gold producer with an annual production of about 285 000 troy ounces.
In contrast to the volcanogenic massive sulphides of the Black Sea region, the ore at Kisladag is in porphyry-type mineralization. It grades up to 1 g/t gold with softer, oxidized material at a depth of 30–80 m.
Serkan Yüksel, Mine Manager at Tuprag, explains that the company plans to more than double its ore production by 2014. Since Tüprag took over mining from a contractor in 2008, the operation has relied on two Atlas Copco DM45 blasthole drill rigs for production drilling. Then in mid-2011, it took delivery of a new Pit Viper PV-235. Together, the three rigs completed 650 000 drillmeters in 11 months.
“That’s over 58 800 individual holes,” notes Yüksel, “and during the first four months, the Pit Viper contributed around 70 000 m to that total. We are using it in the harder rock in the pit so we’re not really in a position yet to make direct comparisons with the DM45 rigs.”
The Pit Viper is powerful and can drill a 12 m hole in one pass,” says operator Yasar Senturk. “You can also move the rig from setup to setup without lowering the mast which is a big advantage. That means you can drill an extra five holes each shift.”
Both ore and waste are drilled on a diamond pattern, with a 4.5–5.25 m burden and slightly larger spacing. 152 mm holes with a COP 54 Gold hammer or 165 mm blastholes with the COP 64 Gold hammer cover the depth of a 10 m bench, with typically 800 mm of sub-drilling.
However, the blasthole rigs are not the only Atlas Copco rigs that have helped make Kisladag successful. The mine also runs a ROC L6 (renamed FlexiROC D50), equipped with a QLX 35 hammer primarily for presplit holes for wall control. The rig drills 20 m double bench holes with a diameter of 95 mm and 1 m of sub-drilling. The layout involves a spacing of 1 m per hole around the entire pit periphery, requiring very accurate rig set up to achieve parallel drilling.
“Another challenge is that the pit slope varies from 65 to 77 degrees, depending on the geotechnical sector from area to area,” Yüksel explains, “and we have experimented in the past with both single and double plane inclined holes.”
Both mining contractors Eti Bakir and Tüprag have chosen to maintain their equipment themselves. Nonetheless, the Atlas Copco local service teams keep a watchful eye on both operations. Atlas Copco service technicians visit Murgul regularly every week, alternating between the surface and underground mines and making sure that the equipment is running well.