THE CONFERENCE CALLER: Moves are afoot to size up a portion of what is arguably the biggest deposit in Western Australia’s Mid West iron ore inventory via RC and core drilling at the western end of the ore body. By Mark Fraser
Mount Ridley Mines (ASX: MRD) is set to tackle its Weld Range West project in earnest as it looks to establish an initial 5 to 30 tonnes per annum direct shipping ore (DSO) operation.
The company controls 20 per cent of Weld Range, with its holdings covering four parallel banded iron formations units (BIFs), each with a strike length of over 10 kilometres – including the highly prospective Madoonga and Wilgie Mia formations.
Located around 330 kilometres north east of Geraldton and 60km north west of Cue, Weld Range’s BIFs extend over 60km. The presence of iron ore in the area has been acknowledged by the WA Government since the 1950s.
According to Mount Ridley Mines technical director David Crook, the company initially plans to drill 15,000 metres as it further distinguishes the project’s hematite – which goes down 120m from surface and will make up the DSO – from the magnetite mineralisation beneath it.
While substantial resources of iron ore have been defined in the remaining 80% of Weld Range held by Sinosteel Midwest Corporation and Fenix Resources (ASX: FEX), to date no drilling has tested hematite targets within Mount Ridley’s tenure.
Combined, the Madoonga and Wilgie Mia formations have an average grade of over 62.5 per cent iron.
“We want to do one more round of gravity – to help further distinguish the magnetite from hematite – and once that’s done we will be ready to drill,” Crook told Resources Roadhouse during the recent RIU Explorers Conference in WA.
“We want to define where the hematite-magnetite interface is – plus we want to determine the overall quality of the hematite.
“Weld Range’s hematite tends to be high grade, so we will be looking for material above 60 per cent iron, hopefully 62-63 per cent, and we are after ore with low silica and low phosphorous in particular, but with high iron.
“The plan is to drill down to 200m panels with RC drilling, but if we like what we see we will consider bringing in a diamond rig.”
When pressed on whether Mount Ridley was also interested in mining Weld Range’s underlying magnetite material, Crook said at the moment that was “a step way too far for us”, and suggested that Sinosteel would most likely become the region’s magnetite leading producer.
“Large magnetite projects with their associated processing circuits can cost billions of dollars, whereas with hematite it’s pretty much a case of digging it up, crushing it, putting it on a truck and sending it off,” he noted.
“Plus there’s been no drilling for hematite of any note within our project area – there are a couple of holes drilled for gold, and a couple of holes maybe drilled mainly for magnetite, but the hematite areas have never been drilled.”
Planning for the approaching field work was influenced by a rock chip sampling program that was conducted in 2020, which returned encouraging results between 60.3 and 63.2 per cent iron.
“With the outcropping we consistently got above 60 per cent in our rock chips – and that was over quite long areas,” Crook said.
The company, however is also interested in what is beneath the ground – including big structures that intersect the BIFs, the strike parallel structures as well as the hydrothermal cells where alteration between magnetite and hematite took place.
“A lot of it is undercover, and that might be one of the reasons why people haven’t explored it before,” Crook said.
“For much of the rest of the belt the iron sticks out of the ground. That’s quite visual – whether it is prospective or not. But in our area, some of the prospective material is underground.
“And that bodes well, I think, because often the material which is not prospective is full of silica, and therefore it tends to stick out of the ground because it is quite resistant to weathering.”
The final good news about Weld Range West is the fact the deposit isn’t landlocked – there is a nearby sealed road which will allow the mined ore to be trucked to the Geraldton port.
This Mid West harbour is the same one from which WA’s first iron ore was shipped by Western Mining back in the mid-1960s.
WMC was an active carbon steel materials miner in the region for some 10 years before, presumably, the rapidly growing iron ore industry in the Pilbara further north overwhelmed the domestic sector.