There was a man that held all the records of both of the cemeteries in Leadville, he has since given them to the Visitors bureau. You can stop there and view them. If you had twins that died, they may have been buried in St. Joseph's cemetery. Check there too!
I do not live in Colorado but go every other summer. I have done lots of research in Leadville! Some of the places that help are
1. The county court house located in Leadville. The people there are very friendly and even let me into the vault to research my records. They have burial cards from some of the mortuaries that have closed. I found those cards to hold lots of information and helped with finding my relatives graves.
2. The librarian at the Leadville library is great. lakecountypubliclibrary.com She helps with anything they have and is a great person to boot! Her name is Janice Fox! She runs a Facebook site called Colorado Mountain History.
3. The usgenweb.com site, Colorado state, Lake County webpage and the Trails of the Past Lake County site run by Gail Kilgore is wonderful. She is very helpful too!
I hope you find what you are looking for. I have Trevethan, Thompson, Gossage, Gilroy, Hewitt, Sweeney, Foreman, Aude and Pierce that I am researching in Leadville.
Happy Hunting and I hope you find the graves you are looking for.
Sheree' Clark Belanger