The Telfer Project is owned and operated by Newcrest Mining Limited and its subsidiary, Newcrest Operations Limited.
On November 6, 2023, Newmont Corporation completed the acquisition of Newcrest Mining Limited to create the world’s leading gold company with robust copper production.
- subscription is required.
Summary:
The Telfer deposit and the group of tenements lie within the north-eastern portion of the Yeneena Basin, which is an irregular-shaped sedimentary basin that lies to the east of the Pilbara Craton, west of the Canning Basin, and north-east of the Savory Basin.
The Telfer gold-copper deposit is divided into the West Dome open pit operation and the Main Dome underground operation, including six upper M-Reefs, which form part of the Main Dome mineralization complex and consist of high-grade and narrow, bedding-concordant veins within the deposit.
The geology of the Telfer deposit area consists of a late Proterozoic sequence of marine sediments that have been weakly metamorphosed, structurally deformed by folding and faulting,, and locally intruded by granites.
The Telfer Dome is composed of sedimentary units from the Telfer Formation and the the Malu Quartzite Member. Gold and copper mineralization are hosted within both formations. The Telfer Formation is subdivided into seven units that include mostly sandstones and siltstones. The Malu Quartzite Member is conformably overlain by the Telfer Formation and subdivided locally into five main stratigraphic units, mainly quartz sandstones and altered sandstones. Weathering locally modified mineralization to depths typically up to 200 m, with the the boundary between oxide and primary mineralization being irregular.
The topography at the Telfer mine site is dominated by two large-scale asymmetric dome structures with steep west-dipping axial planes. Main Dome is located in the south-east portion of the mine and is exposed over a strike distance of 3 km north-south and 2 km east-west before plunging under the transported cover. West Dome forms the topographical high in the northwest quadrant of the mine and has similar dimensions to Main Dome.
Gold and copper mineralization is contained within narrow high grade reefs, pod-like mineralized bodies, sheeted vein sets and low grade stockworks hosted by Proterozoic sedimentary rocks. Copper mineralization is also contained within chalcopyrite, chalcocite and bornite sulfide species.
The Havieron gold-copper deposit comprises a series of nested vertically extensive breccia columns cut up through and along the margins of an ovoid zone (700 m by 400 m) of pervasive hydrothermal alteration intruded by multiphase dykes (calc-silicate/calc-sodic). The breccia columns coalesce into a large volume of mineralization occurring along the contacts of the diorite dyke complex, trending north-west to south-east and dipping south-west. Hydrothermal breccias are volumetrically most important where they coalesce to define the SE Crescent Zone. A north-north-east striking post-mineralization dolerite dyke traverses the deposit.
The Camp Dome project area is a complex domal structure comprising 17 Mile Hill Dome and its two subsidiary domes, Camp Dome and Pajero Dome. Camp Dome is within a doubly plunging anticline. It is a large north-west to south-east trending open fold with similar characteristics to Telfer Dome. The stratigraphy is interpreted to be Middle Malu Member to Lower Malu Member. Surface copper anomalism occurs at the crestal region of the dome and is interpreted to be equivalent to mineralization at Telfer.
The O’Callaghans polymetallic deposit lies at the contact between the Proterozoic Puntapunta Formation and the O’Callaghans granite. The Puntapunta Formation conformably underlies the Wilki Quartzite and overlies the Telfer Formation and is described as an outlier carbonate shelf deposit consisting of well-bedded clastic dolomite and limestone, with lesser amounts of calcareous sandstone and siltstone. The O’Callaghans granite has been identified at around 350 m below the surface. Drilling has defined a zone of polymetallic skarn mineralization up to 60 m thick above the granite/limestone contact.
The Telfer Satellite deposits include Big Tree, Ironclad (or Backdoor West), and Dolphy gold prospects. The Big Tree deposit is located 25 km southeast of Telfer mine within the north-east flank region of Connaughtons Dome and is hosted by upper Malu Formation equivalent strata. Mineralization occurs within a host sandstone unit traceable over 900 m along the the strike. Structural interpretation suggests the plan view of the the mineralized envelope is sigmoidal along strike. The Backdoor deposit is located within the core region of Trotmans Dome and is hosted by steeply dipping Middle Malu Member stratigraphy. Exposure at Backdoor is dominant by two outcropping, notably limonitic quartz veined and “pocked”, sericitized,, and silicified sandstone units. The Dolphy deposit occurs within the southwest flank of Trotmans Dome. It is hosted within Upper Malu Member strata, and mineralization at Dolphy is potentially hosted by an M-Reef equivalent unit.
Mineralization is generally found within high-grade reefs and lower-grade stockworks (i.e., the complex formation of compact but irregularly oriented veins) across three distinct areas:
- near-surface stockwork and reef mineralisation within Main Dome and West Dome;
- underground stockwork and reef mineralisation directly below the Main Dome; and
- vertical stockwork corridors that occur at depth below existing underground mining operations.
Copper minerals generally occur as sulfides, such as chalcopyrite, chalcocite, and bornite. Gold minerals generally occur as free grains that are associated with sulfides. Oxide mineralization (of economic significance) has largely been exhausted from past mining.
The Havieron gold-copper deposit primarily comprises sulfide mineralization (i.e., chalcopyrite and pyrite) across an ovoid-shaped zone of approximately 650m in length and 350m in width (and at depths of up to 1,200m). Initial drilling indicates higher occurrences of mineralization closer to the surface, which progressively declines at depth. Mineralization occurs generally in two separate zones known as the Southeast Crescent Zone (with high-grade gold mineralization associated with sulfides) and the Breccia Zone (which continues to be defined through exploration drilling and early-stage evaluations).
O’Callaghans and Camp Dome are two standalone deposits that lie within 20km of the Telfer deposit, while the Satellites deposits represent an additional group of deposits peripheral to the mine (albeit only 5 mt has been reported to date). Mineralization at O’Callaghans primarily comprises tungsten, copper, zinc, and lead (as well as some elements of molybdenum and silver). On the other hand, Camp Dome is a copper-only deposit. Gold is not present in economically significant amounts at either of the deposits.