Colorado’s proposed tourist‑mine rules include a number of operational changes aimed at reducing risk on tours and clarifying operator responsibilities.

Key safety changes presented by DRMS staff include a requirement that a competent person perform a daily inspection of the tourist mine and that a dated record of each inspection be completed and retained for three years. The draft also adds a 19.5% minimum oxygen‑by‑volume requirement for active workings and tour travel areas; DRMS told operators it prefers calibrated electronic oxygen meters that provide real‑time percentage readings and suggested chemical analysis (for example, Dräger tubes) as a backup.

The draft requires documentation of escape routes and tour‑route maps, annual safety training records for employees and daily examination records. DRMS added emergency‑evacuation and fire‑suppression standards derived from federal best practices and moved several 30 CFR provisions into state rule text to avoid referencing external federal language.

Operators raised practical questions about cost and implementation. Several operators noted small or startup tourist mines may rely on simpler oxygen badges that indicate a safe range rather than a meter showing exact percentage; DRMS said a petitioner could request a modification for particular field conditions but that real‑time meters are the preferred compliance method. On tourist instruction, participants recommended swapping the word “training” for “instruction” or “explanation” to avoid industry‑level task‑training implications and unintended legal exposure; DRMS said it would consider that edit to preserve the safety intent while limiting legal risk.

What happens next: DRMS asked operators to flag which provisions are primarily editorial or non‑substantive and which require more deliberation; staff said some clarifications and small edits will be circulated to stakeholders before a continued hearing date is set.