Waste Disposal at the Magmont Mine,
Bixby, Missouri
FRANKLIN H. SHARP, Mill Superintendent
Magmont Mine
Cominco American, Incorporated
Bixby, Missouri
INTRODUCTION
The objectives of this paper are to present a reasonably typical example of a
non-ferrous mining and milling operation, and, hopefully, to strike a responsive
chord with people in other industries whereby new ideas can be forthcoming.
Since early colonial times, lead has been produced from the "Old Lead Belt" of
Southeastern Missouri. In the 1950's a new deposit was discovered about forty miles
to the west, across the St. Francis mountains. The St. Francis mountains are
mountains in name only, but are important geologically. The New Lead Belt, which
now produces the major share of the United States' lead requirements, is shown on
this map of Missouri.
This lead development is largely in, and adjacent to, the Clark National Forest.
The Clark differs from most of the rest of the national forests in that its lands were
purchased—largely in the 1930's. As a result, it is interspersed with private lands.
Because the land was not always in the Public Domain, the deposits were not
available to acquisition by location, but are leased on a royalty basis from the U. S.
Forest Service. Private lands were, of course, obtained by negotiation with the
owners. This Forest Service map shows the location of the current mines, and, also,
the relative proportion of private and federal land.
Exploration drilling on what is now the Magmont mine was begun about 1960,
and in September 1962, after 62 dry holes, the first ore was discovered. By the end
of 1964, 200 additional holes had been drilled, and the owners, Cominco American
Incorporated and Dresser Minerals Division of Dresser Industries, decided to proceed
with development. Construction started in 1965 and the first ore was milled in June
1968.
The New Lead Belt lies in the Ozark hills, a land poorly adapted to agriculture,
and relatively sparsely settled. The hills are only a few hundred feet high, but steep,
and heavily wooded—mostly with scrub oak. The orebody, containing lead, zinc,
copper and silver minerals, lies in a nearly horizontal bed of dolomite named the
Bonneterre formation which dips to the south at about 20 feet a mile. At the
Magmont mine, the orebody is mined through a nineteen foot diameter,
concrete-lined, vertical shaft, 1,222 feet deep. There are two smaller shafts for
ventilation. Mining is by drilling, blasting, loading, hauling to an underground
crusher, and then hoisted to the surface. Most underground equipment is diesel
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