Before US Steel Ownership

Pittsburgh industrialist Henry Oliver forms the Oliver Iron Mining Company (OIM) in 1890 to realize the potential of ore reserves on Minnesota's Iron Range.
In 1892, OIM leases Mesabi Mountain ore formation. In 1894, OIM leases ore properties owned by John D. Rockefeller who acquired them from the financially-strapped Merritt Brothers. Other leased properties included the Hull-Rust Mine.
In 1899, Henry Oliver looks into building his own railroad from his mines to Lake Superior, but was never built. Oliver felt Rockefeller's Duluth, Missabe & Northern railroad was overcharging his company for ore transportation.
In 1901, OIM and the Rockefeller ore properties come under control of the giant new United States Steel Corporation.

Mining in the Mines

In 1895, steam-powered shovels arrive on the Mesabi at the Mahoning Mine. The shovels had a two-cubic yard capacity.
In 1919, steam shovels arrive with the boom fixed on the crane house and the whole crane house revolving.
OIM's famous steam-powered Shovel #3 could fill a 50-ton ore car with three shovel loads. It was electrified in 1927.
The first electric-powered loading shovel on crawler tracks arrived on the Iron Range in 1924. OIM put electric shovels into service in 1927.
OIM used electric shovels made by Bucyrus-Erie, Marin and P&H in the Hibbing-Chisholm, Eastern (Virginia) and Canisteo (western Mesabi) districts. Bucket capacities of five to six cubic yards were common.
Overburden was later removed by walking draglines.
Stripping dumps were created by erecting a wood railroad trestle and dumping waste material from it. The material fell in a 3-4-5 triangle. Track was then moved sideways and the dump was widened.
The first blasthole drills were 480-volt electric Churn Drills. These machines pounded a steel shaft with a bit on the end into the ore bank. Dynamite was used as the explosive.
In the 1950s, blastholes were made with 4,180-volt electric Rotary Bit Drills. The explosive used was the much cheaper AmFO (Ammonium Nitrate and Fuel Oil).

Railroads in the Mines

In the early days of mining, narrow-gauge 0-4-0T steam locomotives and four-wheeled cars were used to transport both ore and waste material.
The economics of direct shipping ore dictated using standard gauge. O-4-0 and 0-6-0 steam locomotives moved 20 cubic yard side dump cars. The cars later increased in capacity to Austin-Western 30-yard, and Difco 40/50-yard cars.
During the late 1950 and early 1960s, Baldwin cow-calf diesel locomotives were tasked with moving four 30-yard and five 40-yard side dump cars out of the mines. Single unit Baldwins and Alcos could handle four 30-yard and one 40-yard side dump car consists.
DM&IR mainline ore cars increased in capacity from 50 to 70 tons.
OIM 0-8-0 steam locomotives could handle 18 loaded Missabe cars out of the mines. The Lima built switchers were the most powerful.
The first diesel locomotives to arrive in the mines were Alco HH-1000 "High Hoods"
Baldwin VO-1000, DS-4-4-10, S-12 and S-8 cow/calf locomotives compromised a majority of the mine railroad power, followed by EMD SW-9, SW-1200 and TR-6 cow/calf models and in third place were Alco S-2, RS-2 and S-6 cow/calf models.
In about 1950, railroad runs became longer with the opening if the Sherman crushing/sizing plant. Ore was brought to this facility from the Fraser, Forester, Sharon and other mines in the Sherman Group and from the Monroe Group.

Railroad Trackage in the Mines

While trucks grew ever larger and conveyor belts were used on steep grades, OIM favored rail transportation, especially in the Hull-Rust-Mahoning, Monroe Group, Sherman Group, Coleraine and Rouchleau mines.
The Hull-Rust-Mahoning Mine had 70 miles of track.
OIM used locomotive cranes to put 39' panel track sections on bulldozed roadbed.
Whitcomb 65-ton and GE 70-ton locomotives were used in track-laying service.

Ore Washing

Ores on parts of the Iron Range were high in silica which had to be reduced. The first plant to do this was the Trout Lake Washer built in 1910 (closed in 1973)
In the 1940-50 period, washing plants were put into service at Plummer and Acturus to pre-wash ore before sending to Trout Lake. These plants eventually became stand-alone operations.
Washing plants were located at Plummer, Acturus, Hull, Sherman, Rouchleau, Stephens and Pioneer. Rake and screw classifiers were used.

Ore Crushing & Sizing

Crushing and sizing plants were built at Hibbing (Rust Crusher which was erected in 1920), Virginia (Rouchleau Crusher), Sherman, Gilbert, Trout Lake and Stephens.
Screens were installed at Rust Crusher to separate rock from ore via scalpers that dragged the rock from the screens.
In the 1950s, steelmakers demanded that fines be removed from the coarse ore so they didn't have to sinter all the ore they received before dumping it into their blast furnaces. New re-screening facilities were installed at Sherman and Rouchleau.

Ore Concentration

Humphrey Spirals, used to separate ore from rock fines, were installed at Acturus near Taconite and Plummer near Marble.
In 1953, the Acturus Concentrator was the first OIM plant to use "heavy media" separation, followed by Trout Lake (1956), Rust Crusher (1957) and the Sherman (1960). This method treats ore strongly combined with non-ferrous rock. The crushed ore is put in a slurry of ferrosilicon (an alloy of iron and silicone) and due to the specific gravity of the slurry, low-density rock floats and the iron sinks.

The End of Natural Ore

Hull-Rust production ceases in the early 1960s
Pioneer Mine sizing plant shut down in 1967
Rouchleau Plant shuts down in the early 1970s
Sherman Plant is closed in 1981
The Stephens/Donora Plants were sold to J&L Steel, moved to McKinley Washing Plant and finally shut down in 1991.

Final Notes

OIM also had mining operations on the Vermilion Range at Soudan and Pioneer (Ely) underground mines. Mining ceased by 1963.
OIM changed its name to Oliver Iron Mining Division, USS in 1952 and 11 years later, the Oliver name disappeared to become today's Minnesota Ore Operations, USS Corp.
OIM, even though it controlled 72% of the Mesabi's reserves, had competitors. These were Cleveland-Cliffs Iron Mining Co., M.A. Hanna, Pickands, Mather & Co., Pittsburgh-Pacific and Snyder Mining Co.

Information provided by MRHS members Ben Imbertsen and Bruce Kettunen.