If it is not leaking fluid what makes you think it has calcium or anything else in the tire for weight? Some modern patches are put in the tire thru the outside. They have a rubber plug that is pushed in and a round patch opens up on the inside of the tire the gun pulls the plug back out. The plug is cut off like normal on the outside of the tire. To fix it correctly have a boot type patch put on. I have ran new E range tires patched this way and have driven the tires past the legal limit with no more flats or leaks. Just be glad the tire can be saved. much worse case would be catching a steel T type fence post and ripping the sidewall out.