A report into Astra Resources’ Philippines Cayagan River iron sands project has indicated it is economically viable and could become a significant export business. The report was commissioned by the project’s joint venture partner Cayagan River Construction and Development Corporation (CRCDC) to identify the iron ore potential of the dredging area in the Cayagan River delta. The area covers most of the northern shelf of the Cagayan province in Luzon’s northeast.
Astra’s chief executive officer Dr Jaydeep Biswas says the main material to be dredged within the river sediments and offshore sands contains magnetite which is the principal iron bearing mineral. “Large offshore deposits of magnetite have accumulated from the discharge of the Cagayan River and other rivers that empty through the sea, with much of the deposits dating back through many geological eras.
“Magnetite is resistant to weathering and is therefore preserved through the geological ages in its primary form and composition. The highly magnetic nature of magnetite means it can be recovered with relative ease using magnetic separators, making it an economically attractive mineral to recover,” says Dr Jaydeep Biswas.
In recent years, a number of major offshore exploration programs have been conducted in the river delta and shelf area with samples from a 2009 program showing the mineralogical composition of the iron sands at 75% magnetite and 25% rock forming minerals.
Another program showed the average content of the magnetic fraction at 46.2% at a seabed depth of one metre, increasing to 49% at depths of 3-5.5 metres. The iron content recovered from these samples ranged between 53-67%
Astra’s managing director Silvanna De Cianni believes the inferred resources outlined in the shelf area support the potential economic grades of iron present in the dredging area that will in turn allow the company to build the project into a significant export business. “The inferred estimate of magnetite-rich sand in surrounding areas using data from a previous offshore exploration program is about 13 billion tonnes, while magnetite-rich concentrate is about 4 billion tonnes.”
CRCDC is preparing to start its dredging contract at the Cagayan River Delta mouth, and has positioned a concentrator plant at its Port Irene area to transport and process the dredge material for magnetite recovery.