77 sunset strip, page-37

Buffett

Orga is quoting a generic hematite of 5.2 for a 100% Fe content.

Bear in mind that unlike pure gold, 100% Fe content does not exist.

The SG of Brockman hematite is higher than Marra Mamba hematite.

The following examples will show how the weight of hematite varies from ore to ore and remember we are not referring to 100% Fe content.

Hamersley hematite = 4.3t per cubic m
Mt Whaleback Brockman = 3.85t per cubic m
Mt Whaleback Marra Mamba = 2.8t per cubic m

Cheers!