# Relationship history for MSHA mine 4200941

Current hierarchy: **Summit Materials LLC → Kilgore Contracting → HIGHLAND PIT**

- 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:** Harold  Elam → HIGHLAND PIT; 1950-01-01 to 2011-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Warburton Inc → HIGHLAND PIT; 1950-01-01 to 1978-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Warburton Inc → HIGHLAND PIT; 1950-01-01 to 1978-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Warburton Inc → Warburton Inc; 1950-01-01 to 1978-03-31; source msha-controller-operator-history
- **operator_operates_mine:** Ashrock Inc → HIGHLAND PIT; 1978-04-01 to 1987-04-22; source msha-controller-operator-history
- **controller_controls_mine:** Lloyd K  Ash → HIGHLAND PIT; 1978-04-01 to 1987-04-22; source msha-controller-operator-history
- **controller_controls_operator:** Lloyd K  Ash → Ashrock Inc; 1978-04-01 to 1987-04-22; source msha-controller-operator-history
- **controller_controls_mine:** Harold  Ruf et al → HIGHLAND PIT; 1987-03-12 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Westroc Inc → HIGHLAND PIT; 1987-04-23 to 1990-02-22; source msha-controller-operator-history
- **controller_controls_operator:** Harold  Ruf et al → Westroc Inc; 1987-04-23 to 1990-02-22; source msha-controller-operator-history
- **controller_controls_operator:** Mike  Ellis et al → Westroc Inc; 1987-04-23 to 1990-02-22; source msha-controller-operator-history
- **operator_operates_mine:** Westroc, Inc. → HIGHLAND PIT; 1990-02-23 to 2013-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Cyrus W  Spurlino → HIGHLAND PIT; 1990-02-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cyrus W  Spurlino → Westroc, Inc.; 1990-02-23 to 2013-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Summit Materials LLC → HIGHLAND PIT; 2011-04-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Kilgore Contracting → HIGHLAND PIT; 2013-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Harold  Elam → Kilgore Contracting; 2013-04-01 to 2011-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Summit Materials LLC → Kilgore Contracting; 2013-04-01 to current/open; source msha-controller-operator-history