Researching to determine your property's mineral rights is not a function of the assessor's office but we can offer a general direction from where to begin your search. Mineral rights may or may not appear on your deed. Deeds are recorded for public record at the Clerk & Recorder’s Office. Since Broomfield has only been a county since 2001, our records are not complete so you may need to contact the legacy county (the county your property was located in before 2001 - Boulder, Weld, Jefferson or Adams).
Due to the complexity of mineral rights research, you may need to hire a real estate attorney or a title company to assist you.