# Relationship history for MSHA mine 1512772

Current hierarchy: **Great Western Resources Inc → New Horizons Coal Inc → Dulcimer #2**

- 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

- **controller_controls_mine:** Bow Valley Industries Ltd → Dulcimer #2; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Bow Valley Coal Resources Inc → Dulcimer #2; 1981-03-01 to 1986-02-02; source msha-controller-operator-history
- **controller_controls_operator:** Bow Valley Industries Ltd → Bow Valley Coal Resources Inc; 1981-03-01 to 1986-02-02; source msha-controller-operator-history
- **controller_controls_mine:** Bobby Joe  Hensley → Dulcimer #2; 1982-10-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Day Branch Coal Company Inc → Dulcimer #2; 1986-02-03 to 1986-03-16; source msha-controller-operator-history
- **controller_controls_operator:** Bobby Joe  Hensley → Day Branch Coal Company Inc; 1986-02-03 to 1986-03-16; source msha-controller-operator-history
- **operator_operates_mine:** Bow Valley Coal Resources Inc → Dulcimer #2; 1986-03-17 to 1987-02-03; source msha-controller-operator-history
- **controller_controls_operator:** Bow Valley Industries Ltd → Bow Valley Coal Resources Inc; 1986-03-17 to 1987-02-03; source msha-controller-operator-history
- **operator_operates_mine:** New Horizons Coal Inc → Dulcimer #2; 1987-02-04 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Great Western Resources Inc → Dulcimer #2; 1987-02-04 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Great Western Resources Inc → New Horizons Coal Inc; 1987-02-04 to current/open; source msha-controller-operator-history