TNM Drill Down: Ramelius at Mt. Magnet posts week’s best gold assay
Our TNM Drill Down features highlights of the top gold assays of the past week. Drill holes are ranked by gold grade x width, as identified by our data provider Mining Intelligence.
Assays from Down Under led two from the Americas for the best gold drill results of last week. Australia’s Ramelius Resources (ASX: RMS) is drilling to expand Mount Magnet, which it acquired from Harmony Gold in 2010 and restarted the next year. Osisko Development (TSXV: ODV) is drilling at the Trixie test in mine at the Tintic project in central Utah. Challenger Exploration (ASX: CEL) is using its assays to prepare a resource estimate at El Guayabo in Ecuador.
Ramelius cut 60 metres grading 7.8 grams gold per tonne from 448 metres downhole at Mt. Magnet for a grade x width of 468. Mt. Magnet, 500 km northeast of Perth, has produced more than 6 million oz. gold since discovery in 1891. The 225-sq.-km site includes the Eridanus pit, the Hill 60 underground deposit and the Shannon underground lode.
Eridanus, a new discovery in 2017, shows gold mineralization associated with an east-west trending granodiorite bound to the north and south by feldspar-phyric porphyry units. According to a September 2022 report, across all resource categories Eridanus holds 19 million tonnes at 1.2 grams gold per tonne for 760,000 oz. gold, including probable reserves of 2.7 million tonnes at 1.3 grams gold.
The Hill 60 underground deposit was mined through a shaft access until the 1940’s and an open pit mining remnant lode in the 2000’s before being restarted in 2019. It holds probable reserves of 400,000 tonnes grading 3.2 grams gold per tonne for 41,000 ounces.
Shannon’s lode is centred on a quartz vein within a granodiorite unit. Drilling since 2016 has defined the lode continuing below the pit for about 300 metres. It has 324,000 probable tonnes grading 5.2 grams gold per tonne for 54,000 oz. contained metal. Mining began in 2019.
Osisko Development’s hole TRXU-DD-23-003 at Trixie in Utah cut 686 metres grading 62.8 grams gold per tonne from 38.3 metres for a grade x width of 430.95.
The company has completed 35 drill holes for 3,226 metres in its 5,000-metre drilling program this year, it said in a May 17 news release. The drilling is targeting mineralized domains and extending into the footwall to the west to test for parallel zones. Two underground diamond drill rigs are operating and 1,390 metres of the Trixie portal and underground decline ramp have been completed. Osisko expects the ramp to reach the 625-metre level by the third quarter. The company also plans to start targeting copper mineralization then.
“High-grade gold and silver is observed in the footwall of the T2 and T1 zones, as both disseminated and vein mineralization,” Osisko Development president Chris Lodder said in the news release. “The drillholes are intersecting all zones within the deposit area and continue to build upon the exploration successes achieved in 2022. We are also excited to launch our initial drill campaign to target copper porphyry potential at Tintic.”
In hole GYDD-23-039 at the El Guayabo gold and copper project in Ecuador, Challenger Exploration cut 805.3 metres grading 0.5 gram gold per tonne from 4.6 metres for a grade x width of 402.65.
The assay is part of results from Australia-based Challenger’s phase two drilling program to generate an initial mineral resource estimate this month for the GY-A and GY-B anomalies at the site about 550 km south of Quito, the capital.
“This is another solid set of results which pave the way for our first resource in Ecuador,” Challenger managing director Kris Knauer said in a May 18 news release. “Adding to the potential it appears that GY-B and GY-C join forming one continuous zone at least 700 metres wide, open at depth and in both directions along strike. The main discovery zone, or GY-A, also remains open at depth and along strike.”
