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I also had read that there was some low-level beneficiation going on with some early ores, although not to the extent of today's taconite pellet production.

Some early ores were rock-like, as you can see in the remaining cargo in vessels that didn't reach their destination. I don't have a good close-up, but here is a photo of the cargo of the Schooner Albemarle. The Albemarle loaded in Escanaba for Cleveland in November 1867 and was lost just west of Point Nipigon in the Straits of Mackinac. This is from a video I made of it in July, you can see the pile of rocks of various sizes around the remains of the centerboard. At one point in my video I pick up a small, flat piece of iron that looks like an arrowhead, but reddish and a bit shiny. This entire pile is iron ore, as it stands above a sandy bottom.

Russ wrote:I believe the process of iron ore beneficiation was not routinely used until taconite became the principle source of iron ore.

On parts of the Mesabi Range, particularly on the west end, the Ore was relatively high in Silica which required benefication in the form of washing to reduce the Silica content. The first plant was built at Trout Lake in 1910, closed in 1973. Additional plants were built at Plummer Mine and Arcturus Mine. These started out as washing plants and later received Heavy-media separators, and in the '50s they received Humphrey Spiral separators. With the end of Natural Ore mining both have closed and have been dismantled. These were just the ones owned by US Steel, there were others.

I've heard that the ore out of the Cuyuna Range was generally shipped as crushed rock, as opposed to the dirt-like ore of the Missabe Range. Is that accurate? Also curious about Vermillion ore - that would seem more likely to have been rock like, coming from primarily underground operations.

I believe the process of iron ore beneficiation was not routinely used until taconite became the principle source of iron ore. Taconite is a difficult ore to mine (the ore has a hardness of 10, essentially the same as diamonds) and has a relatively low iron content (15 to 30 percent iron). Beneficiation results in a pellet with uniform iron content (usually 62 - 64 percent iron) that is economically viable to ship. Prior to the use of taconite and beneficiation, the mines just scrapped off the over burden and shipped the ore from naturally enriched iron deposits. The natural ore deposits ranged from 45 to 60+ percent iron. Up until the transition to taconite, there were more than 90 varieties of iron ore that were shipped on the lakes (based on iron content and/or impurities in the ore).75G2

This is red ore from the Mesabi Range. Can't remember if we were unloading in Gary or Conneaut.


http://newsearch.boatnerd.com/download/ ... &mode=view

The natural iron ore from the Mesabi Range was the consistency of soil, while ores from the Marquette and Gogebic Ranges were clumpy. The mines would use a process called "benefication" to remove the impurities, mainly to reduce the silica levels in the iron ore.

How were impurities removed from natural ore when it was mind such as soils and other minerals? In old images it appears clumpy and possibly mixed with dirt.