# Relationship history for MSHA mine 2601725

Current hierarchy: **T F S Inc → Chalk Mountain Associates → Chalk Mountain Mine**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Chalk Mountain Associates → Chalk Mountain Mine; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** T F S Inc Et Al → Chalk Mountain Mine; 1981-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** T F S Inc Et Al → Chalk Mountain Associates; 1981-04-01 to current/open; source msha-controller-operator-history