Hello Everyone :-)

I've removed the linoleum and tar glue and I've begun to sand the kitchen floor. My father and I believe the floor is pine, but its yet to be determined officially. The house is 1928. My problem is that the sanding is taking forever and I'm using a portable 3" belt sander with they heay removal belt from craftsman to get it down to the wood.

Any suggestions for speeding up the sanding process? Am I using the right belt to start with?

Also, there is a finish of some type hit and mis on the floor that may be causing the sanding to take longer than I expected. Any ideas what the finish could be? Wax? Lime? Oil? It doesn't look like a varnish, just colored.