Oyu Tolgoi continues to grow in stature – more copper, gold and molybdenum
The April and May issues of International Mining include articles on the great Oyu Tolgoi development in the Gobi Desert of southern Mongolia. Ivanhoe Mines and BHP Billiton have just announced the new discovery of a zone of shallow copper-molybdenum-gold mineralisation some 10 km north of the Ivanhoe Mines/Rio Tinto Oyu Tolgoi copper-gold mining complex currently under construction. The discovery, known as Ulaan Khud North, extends the known strike length of the Oyu Tolgoi mineralised system by an additional 3 km to the north, to more than 23 km.
Less than half of the 23-km-long mineralised trend at Oyu Tolgoi has been extensively drill-tested to date. An ongoing exploration program including proprietary, induced-polarization (IP) technology has identified additional exploration and development targets.“The Ulaan Khud North discovery reinforces our longstanding belief that with continued exploration there is excellent potential to discover new porphyry deposits, rich in copper and gold, which are associated with the world-class Oyu Tolgoi mineralized trend,” said Rpbert Friedland, Executive Chairman and CEO of Ivanhoe.
Ulaan Khud North is located on a 19,625-ha exploration licence that is part of Ivanhoe’s joint-venture partnership with BHP Billiton, which was formed in 2005. BHP Billiton has earned a 50% interest in the joint venture, which includes the Ulaan Khud North property, by spending $8 million in exploration costs and conducting an airborne survey using the proprietary FalconTM gravity gradiometer system over the Oyu Tolgoi area.
A total of 25 drill holes (UKD031 to 055) totalling 6,561 m, ranging in depth from 182 to 377 m, defined the new zone of shallow porphyry copper mineralisation over an area of 600 m by 300 m. Most of the holes are vertical and were drilled on a 100-m-square grid. The mineralised zone starts beneath 60 to 80 m of Cretaceous clay and gravels, indicative of a near-surface deposit with open-pit mining potential. Ivanhoe’s geologists believe that the near-surface copper mineralisation discovered to date at Ulaan Khud North may be part of a much larger deposit.
Mineralisation occurs in quartz monzodiorite, similar to mineralised quartz monzodiorites at Oyu Tolgoi. A total of 23 of the 25 drill holes drilled at Ulaan Khud North intersected the mineralised quartz monzodiorite. The mineralisation is porphyry-style stockwork, disseminations and massive veins of chalcopyrite, with molybdenite disseminations and veinlets and trace bornite. Many holes encountered mineralisation with greater than 1% Cu in multiple individual 1 m samples, while almost all holes have longer intervals of mineralisation grading greater than 0.3% Cu. Numerous post-mineral intrusive rocks cut the mineralised quartz monzodiorite and define the boundaries of most mineralised intervals.
“The presence of intensively mineralised and altered quartz monzodiorite and basalt xenoliths within the moderately mineralised quartz monzodiorite supports the idea that an earlier phase of stronger mineralisation exists at depth and along margins of the area,” said Richard Gosse, Ivanhoe’s Vice-President, Exploration..
The mineralisation at Ulaan Khud North starts as shallow as 60 m below surface, much higher than the mineralised zone at Hugo Dummett to the south. The fact that Ulaan Khud North occurs in similar Devonian host rocks to Hugo Dummett suggests that the main Oyu Tolgoi porphyry system trend is relatively shallow in this area and that potential for surface-mineable targets still exist within the Oyu Tolgoi trend and Ulaan Khud North in particular.
The Ulaan Khud North property adjoins the Shivee Tolgoi Entrée Gold-Ivanhoe Mines joint-venture property and is about 3 km north of mineralisation found at Ulaan Khud on that licence.
The Pre-Mining Agreement for the Ulaan Khud North property specifies that Ivanhoe and BHP Billiton have three years to conduct additional exploration, complete an environmental impact study, prepare a final feasibility study and gain approval for the design for the project. The agreement also specifies that a Technical and Economical Study to mine the deposit is required to be delivered to the Mineral Resources Authority of Mongolia (MRAM) by June 30, 2013.
“The Pre-Mining Agreement provides a three-year window to aggressively explore the project and to prepare resource, technical and economic studies. It also paves the way for the Ulaan Khud North Project to obtain all necessary mining permits and approvals,” said Gosse.
This newly discovered mineralisation is just north of the Entrée – Oyu Tolgoi LLC (OTLLC) joint venture ground. As already noted, the discovery, named Ulaan Khud North, extends the known Oyu Tolgoi mineralised trend by a further 3 km. The trend includes the Entrée-OTLLC joint venture’s Heruga deposit, Hugo North Extension deposit and Ulaan Khud zone.
Entrée’s President & CEO, Greg Crowe, commented, “This discovery, while not on the Entrée-OTLLC joint venture property, is located just 3 km north of the joint venture’s Ulaan Khud zone. The strike length of the Oyu Tolgoi mineralised system is now at least 23 km, of which 17 km are located within the Entrée-OTLLC joint venture ground. Less than half of the trend has been extensively drill-tested to date. The discovery of Ulaan Khud North is one more example of the magnitude and scale of the trend and the excellent potential for the discovery of additional mineralised zones.”
Ulaan Khud is a near-surface copper and gold mineralized zone located within the Entree-OTLLC joint venture ground. The Ulaan Khud zone was originally discovered in 2006 during condemnation drilling undertaken as part of an Earn-In Agreement under which the joint venture was formed. Results were released on October 26, 2006, highlights of which include Hole EGD118 (130 m at 0.35% Cu and 0.11 g/t Au) and Hole EGD110 (154 m at 0.34% Cu and 0.08 g/t Au).
Less than half of the 23-km-long mineralised trend at Oyu Tolgoi has been extensively drill-tested to date. An ongoing exploration program including proprietary, induced-polarization (IP) technology has identified additional exploration and development targets.“The Ulaan Khud North discovery reinforces our longstanding belief that with continued exploration there is excellent potential to discover new porphyry deposits, rich in copper and gold, which are associated with the world-class Oyu Tolgoi mineralized trend,” said Rpbert Friedland, Executive Chairman and CEO of Ivanhoe.
Ulaan Khud North is located on a 19,625-ha exploration licence that is part of Ivanhoe’s joint-venture partnership with BHP Billiton, which was formed in 2005. BHP Billiton has earned a 50% interest in the joint venture, which includes the Ulaan Khud North property, by spending $8 million in exploration costs and conducting an airborne survey using the proprietary FalconTM gravity gradiometer system over the Oyu Tolgoi area.
A total of 25 drill holes (UKD031 to 055) totalling 6,561 m, ranging in depth from 182 to 377 m, defined the new zone of shallow porphyry copper mineralisation over an area of 600 m by 300 m. Most of the holes are vertical and were drilled on a 100-m-square grid. The mineralised zone starts beneath 60 to 80 m of Cretaceous clay and gravels, indicative of a near-surface deposit with open-pit mining potential. Ivanhoe’s geologists believe that the near-surface copper mineralisation discovered to date at Ulaan Khud North may be part of a much larger deposit.
Mineralisation occurs in quartz monzodiorite, similar to mineralised quartz monzodiorites at Oyu Tolgoi. A total of 23 of the 25 drill holes drilled at Ulaan Khud North intersected the mineralised quartz monzodiorite. The mineralisation is porphyry-style stockwork, disseminations and massive veins of chalcopyrite, with molybdenite disseminations and veinlets and trace bornite. Many holes encountered mineralisation with greater than 1% Cu in multiple individual 1 m samples, while almost all holes have longer intervals of mineralisation grading greater than 0.3% Cu. Numerous post-mineral intrusive rocks cut the mineralised quartz monzodiorite and define the boundaries of most mineralised intervals.
“The presence of intensively mineralised and altered quartz monzodiorite and basalt xenoliths within the moderately mineralised quartz monzodiorite supports the idea that an earlier phase of stronger mineralisation exists at depth and along margins of the area,” said Richard Gosse, Ivanhoe’s Vice-President, Exploration..
The mineralisation at Ulaan Khud North starts as shallow as 60 m below surface, much higher than the mineralised zone at Hugo Dummett to the south. The fact that Ulaan Khud North occurs in similar Devonian host rocks to Hugo Dummett suggests that the main Oyu Tolgoi porphyry system trend is relatively shallow in this area and that potential for surface-mineable targets still exist within the Oyu Tolgoi trend and Ulaan Khud North in particular.
The Ulaan Khud North property adjoins the Shivee Tolgoi Entrée Gold-Ivanhoe Mines joint-venture property and is about 3 km north of mineralisation found at Ulaan Khud on that licence.
The Pre-Mining Agreement for the Ulaan Khud North property specifies that Ivanhoe and BHP Billiton have three years to conduct additional exploration, complete an environmental impact study, prepare a final feasibility study and gain approval for the design for the project. The agreement also specifies that a Technical and Economical Study to mine the deposit is required to be delivered to the Mineral Resources Authority of Mongolia (MRAM) by June 30, 2013.
“The Pre-Mining Agreement provides a three-year window to aggressively explore the project and to prepare resource, technical and economic studies. It also paves the way for the Ulaan Khud North Project to obtain all necessary mining permits and approvals,” said Gosse.
This newly discovered mineralisation is just north of the Entrée – Oyu Tolgoi LLC (OTLLC) joint venture ground. As already noted, the discovery, named Ulaan Khud North, extends the known Oyu Tolgoi mineralised trend by a further 3 km. The trend includes the Entrée-OTLLC joint venture’s Heruga deposit, Hugo North Extension deposit and Ulaan Khud zone.
Entrée’s President & CEO, Greg Crowe, commented, “This discovery, while not on the Entrée-OTLLC joint venture property, is located just 3 km north of the joint venture’s Ulaan Khud zone. The strike length of the Oyu Tolgoi mineralised system is now at least 23 km, of which 17 km are located within the Entrée-OTLLC joint venture ground. Less than half of the trend has been extensively drill-tested to date. The discovery of Ulaan Khud North is one more example of the magnitude and scale of the trend and the excellent potential for the discovery of additional mineralised zones.”
Ulaan Khud is a near-surface copper and gold mineralized zone located within the Entree-OTLLC joint venture ground. The Ulaan Khud zone was originally discovered in 2006 during condemnation drilling undertaken as part of an Earn-In Agreement under which the joint venture was formed. Results were released on October 26, 2006, highlights of which include Hole EGD118 (130 m at 0.35% Cu and 0.11 g/t Au) and Hole EGD110 (154 m at 0.34% Cu and 0.08 g/t Au).
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