# Relationship history for MSHA mine 4300271

Current hierarchy: **BTR PLC → Lebanon Crushed Stone → Hartland Sand & Gravel**

- Valid-time bounds: inclusive, date granularity
- Null end: open-ended in the upstream history row; not independent proof of present control
- Transaction-time observation: 2026-10-18T09:31:49.615908+00:00

## Valid-time edges

- **controller_controls_mine:** Arthur Whitcomb Inc → Hartland Sand & Gravel; 1950-01-01 to 1986-11-24; source msha-controller-operator-history
- **operator_operates_mine:** Summarsell Excavating Inc → Hartland Sand & Gravel; 1950-01-01 to 1980-06-02; source msha-controller-operator-history
- **controller_controls_mine:** Summarsell Richard → Hartland Sand & Gravel; 1950-01-01 to 1980-06-02; source msha-controller-operator-history
- **controller_controls_operator:** Summarsell Richard → Summarsell Excavating Inc; 1950-01-01 to 1980-06-02; source msha-controller-operator-history
- **operator_operates_mine:** Alan Dunklee Inc → Hartland Sand & Gravel; 1980-06-03 to 1981-09-27; source msha-controller-operator-history
- **controller_controls_mine:** Dunklee Alan → Hartland Sand & Gravel; 1980-06-03 to 1981-09-27; source msha-controller-operator-history
- **controller_controls_operator:** Dunklee Alan → Alan Dunklee Inc; 1980-06-03 to 1981-09-27; source msha-controller-operator-history
- **operator_operates_mine:** Lebanon Crushed Stone → Hartland Sand & Gravel; 1981-09-28 to 1986-11-24; source msha-controller-operator-history
- **controller_controls_operator:** Arthur Whitcomb Inc → Lebanon Crushed Stone; 1981-09-28 to 1986-11-24; source msha-controller-operator-history
- **operator_operates_mine:** Lebanon Crushed Stone → Hartland Sand & Gravel; 1986-11-25 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** BTR PLC → Hartland Sand & Gravel; 1986-11-25 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** BTR PLC → Lebanon Crushed Stone; 1986-11-25 to current/open; source msha-controller-operator-history