Formally Peabody Coal Mine, the empty pits are now a cooling pond for the nearby Braidwood Nuclear Power Plant. Although owned by power company Commonwealth Edison, the area is managed the Illinois Department of Natural Resources as the Mazon-Braidwood State Fish & Wildlife Area. Fishing, hunting and fossil collecting (WM3FKG)
are permitted on this former strip mine in accorandance with the IDNR guidelines.
The fossils are easily retrievable because the coal mine removed approximately 50 feet of "overburden" in order to extract the coal. Within this overburden, coal remnants and odd bits and pieces from glacial deposits can be found, but the main attraction is 300 million year old fossils.
The fossils found in this area are 300 million years old and consist mostly of ferns, clams, and jelly fish. Worms and leeches can also be found, but harder to find because they are smaller. Rare finds include insects and even a Tully Monster
The strategy for finding a fossil is to scour exposed gravel areas free of vegetation. The gravel consists of mostly gray siltstone and slate along with a hodge-podge of glacial deposits. Within all this other material you will occasionally find a rounded brown-orange rock. If you are careful, bisecting this rock along a seam will probably reveal a fossil preserved 300 million years ago.
If the rock does not easily split for you, it is recommended you soak the rock in a bucket of water and then freeze and thaw it over a few weeks to weaken the seam.
Before you are allowed to collect fossils, you must fill
out a permit application and when you finish your collecting, you must fill out a reporting form as well - both of which can be downloaded from the bottom of the IDNR's webpage
Other fossil collecting rules include:
You must park at the designated parking located at N41° 12.149' W88° 13.989'
Collecting is permitted only between March 1 and September 30.
Digging of holes and trenches is prohibited.
And, of course, practice pack in/pack out.
Other notices and warnings:
The distance from the parking area to the dig site is a little over 2 miles one way, so prepare accordingly. A wagon or bicycles is recommended since you will also need to bring in drinking water because there are no drinking or bathroom facilities by the dig site.
Bring plenty of bug repellant. Once it gets warm, the area is known for ticks and chiggers.
Bring sunscreen. It seems the water reflects the UV rays right on to you.