At these co-ordinates, look to the hillside and the Soudan Underground Mine. The owner, US Steel Corp, closed the mine in 1962, and in 1965, donated it to the state of Minnesota to be used for educational purposes. The mine is now a state park (fee) and you can tour the grounds or put on a miner’s hat and tour underground (fee). On July 31, 1884, the first shipment of iron ore in Minnesota was shipped from the Soudan Mine to Two Harbors, MN on Lake Superior. This event marked the birth of Minnesota’s famous “Iron Range.” Iron ore was found here by gold prospector’s searching for gold in the 1800’s. The veins of hematite at this site were extremely rich – often containing more that 65% iron. From 1883-1900, the mine was open pit. They switched to underground mining to improve mine safety. It was improved so much that it earned the nickname “Cadillac of Underground Mines.”
Hematite,the most important mineral of iron ore, common in weathered rocks and soils, but not present in all iron ores. It occurs in these forms of ore: specular iron, micaceous, fibrous, oolitic, and earthy hematite. The soft earthy variety ,also known as red ocher, is used as paint pigment. Most of the iron ore of the Vermilion Range, including the Soudan mine, consists of a hard, metallic, almost black form of hematite. A total of 14 million tons of this ore was removed from the Soudan mine during its operation, working to a depth of 2,341 feet below the surface. In the early years, before mechanization, the heavy ore was hand loaded into ore cars pulled by mules.
The purpose of this earthcache is to show you how heavy one of these pieces of ore was for the miners to hand load into an ore car.
TO GET CREDIT FOR THIS CACHE record these measurements for the left sample of ore on the monument
Length: 13 1/2" Width: 9 1/2 " Height: 24"
Use these averages to calculate the volume of the ore using the formula: V = L x W x H
Next, calculate the WEIGHT of the ore using: W = V x D
Multiply your VOLUME x the ORE DENSITIY (0.18 lbs/in3). Your answer is an estimate of the WEIGHT OF THE ORE SAMPLE in POUNDS.
TO GET CREDIT FOR THE CACHE, SEND AN EMAIL TO ME WITH YOUR ANSWER IN POUNDS.