Mining in the Mt. Vernon Quadrangle
The Herrin Coal was mined on the eastern side of the town of Mount Vernon. Unfortunately, no company maps were found of this mine, and the outline shown on the accompanying map is a general location only. The coal was over 800 feet deep and less than 5 feet thick. In addition to these less than ideal conditions, the roof over most of the mine was thick shale over 20 feet thick and the underclay floor was over 3 feet thick. The gray shale did not hold up well after being exposed to air in the rooms and haulage entries, and it fell almost continuously. The underclay heaved and creeped. The mine was open for 21 years, closing in 1915.