12 ms·
Hmm, maybe I didn't observe that effect. First order went into effect in 1933, and second in 1942. The mine closures seem to be pretty well distributed since
by pp19dd 8y ago
Hmm, maybe I didn't observe that effect. First order went into effect in 1933, and second in 1942. The mine closures seem to be pretty well distributed since then, implying a healthy amount of openings and closures yearly, totaling a summed inventory of 80k mines in the states. Anyhow, ignoring mines prior to 1970, this is the pattern of distribution of mine closures:
1971 475 closures
1972 725 "
1973 692 "
1974 455 "
1975 711 "
1976 1,406 "
1977 1,248 "
1978 2,750 "
1979 5,378 "
1980 4,232 "
1981 2,901 "
1982 3,681 "
1983 2,598 "
1984 2,990 "
1985 4,401 "
1986 2,539 "
1987 1,944 "
1988 2,007 "
1989 1,855 "
1990 1,805 "
1991 1,879 "
1992 1,705 "
1993 1,425 "
1994 1,329 "
1995 1,212 "
1996 1,116 "
1997 1,013 "
1998 994 "
1999 1,151 "
2000 1,041 "
2001 1,368 "
2002 1,521 "
2003 1,450 "
2004 1,266 "
2005 1,298 "
2006 1,431 "
2007 1,465 "
2008 1,564 "
2009 1,664 "
2010 1,669 "
2011 1,894 "
2012 2,371 "
2013 2,752 "
2014 3,636 "
2015 2,622 "
So overall, a fairly steady figure. I imagine they'd go at it until a mine was played out, at least in the economic/profitability sense.