Banded iron formations are critical to our current economy as they are by far the biggest source of economic iron deposits. China and Australia are the world’s largest iron producers, and both have enormous reserves of BIFs. Smaller deposits are mined elsewhere including the USA and Canada.
Banded iron formation in the North Pit area of Sherman Mine, showing … and East Pit iron formations … Subsequent mining from 1974 to 1975 increased the size of the open pit … Subsequent mining from 1974 to 1975 increased the size of the open pit …
In 1981, Wyoming experience its first gold rush in the 20th century after I released a report on gold assays from samples I collected at Bradley Peak in the Seminoe Mountains (some vein samples running as high as 2.87 opt Au, and altered banded iron formation sample that assayed 1.14 opt Au).
Overlying this unit to the west is the Ultramafic-Mafic unit interlayered with banded iron formations. Gold occurs in this unit at Vubachikwe mine, which is adjacent to Blanket, where the deposits are confined to steeply dipping folds in the banded iron formation layers. The Ultramafic-Mafic unit is in turn overlain to the west by the Mafic unit, a thick sequence of tholeiitic and pillow ...
A typical banded iron formation consists of repeated, thin layers (a few millimeters to a few centimeters in thickness) of silver to black iron oxides, either magnetite (Fe 3 O 4) or hematite (Fe 2 O 3), alternating with bands of iron-poor shales and cherts, often red in color, of similar thickness, and containing microbands (sub-millimeter) of iron oxides.
Gold mineralisation of the Kibali district are classified as Archaean orogenic gold deposits. At Kibali the gold deposits are largely hosted in siliciclastic rocks, banded iron formations, and chert that were metamorphosed under greenschist facies conditions. Ore-forming H2O-CO2-rich fluids migrated along a linked network of gently northeast-dipping shears and northeast to NNE- plunging fold ...
Banded iron formations (BIFs) are sedimentary rocks, characterized by the presence of alternating layers of iron-rich minerals - known as magnetite - and amorphous silica-rich rocks - known as cherts. Each layer is relatively thin with varying levels of thickness, measuring from a millimeter up to
Banded iron formation' (BIF) deposits - GEUS. in Greenland. Here, deposits related to banded iron formations (BIF), mostly so-called Algoma type, are typical for Archaean greenstone belts formed in continental rifts or at continental mar- gins.
Banded iron-formations are sedimentary rock formations with alternating silica-rich layers and iron-rich layers that are typically composed of iron oxides (hematite and magnetite), iron-rich carbonates (siderite and ankerite), and/or iron-rich silicates (e.g., minnesotaite and greenalite).
It is noted, however, that other Canadian projects associated with banded iron formations often show significant resources within structurally controlled gold zones outside of or peripheral to the conventional iron formation hosted zones. Results at the Hivogani target confirm this potential exists at the Back River Gold Project.
Mining and processing of banded iron formations involves coarse crushing and screening, followed by rough crushing and fine grinding to reduce the ore to the point where the crystallised magnetite and quartz are fine enough that the quartz is left behind when the resultant powder is passed under a magnetic separator.