The National Stone, Sand & Gravel Association (NSSGA) has been disseminating this list of  “talking points” about how aggregates mining — both surface and underground — is different from coal mines. The organization pointed out these differences as well after the Sago, Aracoma, and Utah and Indiana coal mine incidents in 2006 and 2007, respectively. 

1. Extracted product is non-combustible, non-flammable;
2. No flammable gases such as methane are present; MSHA-approved (permissible) equipment not required in stone facilities such that regular automobiles, trucks and loaders can be used;
3. Extraction methods create large open spaces for access by large equipment; large openings accommodate emergency equipment used by non-facility emergency services;
4. More stable mineral formations resulting in stable mine roofs; minimized needs for additional roof supports;
5. Emergency escape and access easier because of large spaces in mine;
6. Most are only a few hundred feet deep; horizontal tunnel access permits large mobile equipment to easily enter facility;
7. During emergency, more equipment choices available to operators because reduced hazard permits used of “un-approved” equipment;
8. Minimal need for certified mine rescue teams because local fire departments, or emergency services, are able to respond;  
9. Due to size of large open spaces, and mining methods, mechanical mine ventilation usually not required or is minimal; natural ventilation works well.