For the special methods by which placer deposits are mined see Gold.
Grain and fruit are grown in large quantities, and much coal is mined in the vicinity of Kirksville.
The middle states, New York, New Jersey and Pennsylvania, are known to have many great deposits of rich magnetite, which supplied a very large proportion of the American ores till the discovery of the very cheaply mined ores of Lake Superior.
Coal of a bituminous and also semi-anthracite kind is produced, the best mined on the Pacific slope of the continent, the coking coals of the Fernie region supplying the fuel of the great metal mining districts of the Kootenays in British Columbia, and of Montana and other states to the south.
Copper and mispickel are mined only in small quantities.
The mineral occurs generally in lenticular deposits, which may reach a thickness of more than loo ft.; but it is mined only to a limited extent, most of the salt being obtained from brine springs and wells which derive their saline character from deposits of salts.
Asbestos was formerly mined in the western and south-western parts of the state.
The bituminous is of excellent quality for the manufacture of coke and gas, but up to 5902 had been mined only in small quantities.
The block or ground between levels is sometimes mined by underhand stoping (fig.
Lignite is also mined at Bacu Abis, near Gonnesa, and Anthracite in small quantities near Seui.