To find other documentation about your grandfather, make a research plan. You have a good start already -- you have a set of documents.
Start with a timeline and a genealogy source checklist, entering all the documents you have, and listing all the information you know, and how you know it. Then mine all the documents for clues to where you might find other information.
Start a research log and record what you plan to search for, where you plan to search, and how you plan to search -- and then record what your results were.
For example: starting with your grandfather's Petition for Naturalization, make notes about the other people listed in his petition who attested to his character. Can you find them in the 1900 Census or in City Directories in the area? Can you determine how they knew your grandfather? When you are having difficulty searching for someone by name, it helps to have the names of friends, associates, and neighbors that you can search for as well as for your family members. Your grandfather might also be listed on their records, but not be indexed in them.
llinois, County Naturalization Records, 1800-1962," images, FamilySearch (https://familysearch.org/pal:/MM9.3.1/TH-1971-27517-12901-51?cc=1989159 : 20 May 2014), Christian > Petitions for naturalization, special naturalizations 1878-1900 vol B > image 122 of 223; county courthouses, Illinois.
It helps immensely to get a map of the area. During this period, immigrants could naturalize in any county court, and did not have to submit the declaration and petitions to the same court. People were likely to go to whatever courthouse was closest -- and the most convenient courthouse might be across a county border from their place of residence. It is easy to miss someone's census enumeration if they are just over the county border, and you've restricted your search to a geographical area which is too small. Mapping out all the street addresses you might have from family papers can give you a good idea of how much people might have moved.
Steve Morse's One-Step Web Pages can also help in searching the census, and the help/faq pages have much useful information.
I also would not assume that a miner would stay in the same place over many decades. If you can identify others who worked for the same company, see if they go to other mines -- your grandfather may have followed them.
Also check the FamilySearch Research Wiki for the 1900 and 1910 Census for the areas you are looking in. Look for a notice about known issues -- those are the articles where the Wiki describes record loss or other difficulty with the records.
Keep in mind that you may not be able to find your grandfather in any collection if you only search by name. Sometimes browsing the digital images page by page is the only way to find someone.