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美国明尼苏达州是著名的铁矿砂产区,矿脉从本州的东北部向西南延伸,长约100英里,宽1.5～3英里,成蛇形。当地人称之为铁矿脉,正式名称为密萨比铁矿脉(Mesabi Ra-nge)。这里矿层较厚,从地表至600英尺的地下都是矿体,地面土石层不超过30英尺,有些地方只有15英尺,因而最适宜露天大规露开采。这个矿区从十九世纪末开采以来,已有80多年的历史,两次世界大战,加速了这个矿区的开采速度。到目前,含铁量60%以上的富矿已采完,所余者是大量的品位为15～30%的赤铁矿。现集中力量采掘品位17%以上的矿石,
Minnesota is a famous iron ore producing area in the United States. The veins extend southwest from the northeastern state of Honshu. It is about 100 miles long and 1.5 to 3 miles wide, forming a serpentine pattern. Locals called the iron ore veins, the official name for the Mizpai iron ore veins (Mesabi Ra-nge). The thick seam is here, with orebodies down to 600 feet from the surface to the ground, with no more than 30 feet of earth and less than 15 feet in some areas, making it the most suitable for open pit mining. This mining area has been in existence for over 80 years since it was mined at the end of the nineteenth century. The two world wars accelerated the mining of this mined area. Up to now, more than 60% of iron ore has been mined, the rest are a large number of grade hematite 15% to 30%. Concentration efforts are now concentrated mining grade more than 17% of the ore,