# Relationship history for MSHA mine 0504654

Current hierarchy: **Burnco Rock Products Ltd → BURNCO Colorado LLC → Bernhardt Gravel 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **controller_controls_mine:** George W  Hall et al → Bernhardt Gravel Mine; 1988-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hall-Irwin Construction Company → Bernhardt Gravel Mine; 1999-06-01 to 2006-02-07; source msha-controller-operator-history
- **controller_controls_operator:** George W  Hall et al → Hall-Irwin Construction Company; 1999-06-01 to 2006-02-07; source msha-controller-operator-history
- **controller_controls_mine:** George W  Hall et al → Bernhardt Gravel Mine; 2003-07-08 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Hall-Irwin Corporation → Bernhardt Gravel Mine; 2006-02-08 to 2010-07-13; source msha-controller-operator-history
- **controller_controls_operator:** George W  Hall et al → Hall-Irwin Corporation; 2006-02-08 to 2010-07-13; source msha-controller-operator-history
- **controller_controls_mine:** Scott  Masi et al → Bernhardt Gravel Mine; 2009-02-13 to 2017-02-26; source msha-controller-operator-history
- **operator_operates_mine:** Hall-Irwin Aggregates Inc → Bernhardt Gravel Mine; 2010-07-14 to 2012-08-30; source msha-controller-operator-history
- **controller_controls_mine:** George W  Hall et al → Bernhardt Gravel Mine; 2010-07-14 to 2011-07-11; source msha-controller-operator-history
- **controller_controls_operator:** George W  Hall et al → Hall-Irwin Aggregates Inc; 2010-07-14 to 2011-07-11; source msha-controller-operator-history
- **controller_controls_mine:** Bret  Hall et al → Bernhardt Gravel Mine; 2011-07-12 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Bret  Hall et al → Hall-Irwin Aggregates Inc; 2011-07-12 to 2012-08-30; source msha-controller-operator-history
- **controller_controls_operator:** Scott  Masi et al → Hall-Irwin Aggregates Inc; 2011-07-12 to 2012-08-30; source msha-controller-operator-history
- **operator_operates_mine:** BURNCO Colorado LLC → Bernhardt Gravel Mine; 2012-08-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Scott  Masi et al → BURNCO Colorado LLC; 2012-08-31 to 2017-02-26; source msha-controller-operator-history
- **controller_controls_operator:** Bret  Hall et al → BURNCO Colorado LLC; 2012-08-31 to 2017-02-26; source msha-controller-operator-history
- **controller_controls_mine:** Burnco Rock Products Ltd → Bernhardt Gravel Mine; 2017-02-27 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Burnco Rock Products Ltd → BURNCO Colorado LLC; 2017-02-27 to current/open; source msha-controller-operator-history