You can also get a lot of information on them at the My Land Matters sight. See the link in my signature. Go to the maps and select MINING MAPS. GO to the Colorado claims map. Once it loads turn the MINING CLAIMS ACTIVITY layer by clicking on the box and hitting REFRESH MAP (Don't refresh the page with the browser reload button or you go back to step one!) which is the button on the bottom of the map tool bar on the right side of the map. Use the zoom tool to enlarge any area and the move map to move around the map. Once you have zoomed to the area you want to check out, click on the information button and then click the map. a window with all the info for that sector will open up and will often include links for further info.
Land Matters is one of my "go to" sites for research. Learning how to use it is not hard and well worth the time to learn.