# Relationship history for MSHA mine 2200422

Current hierarchy: **Philip  Cockerham; John  Cockerham Jr → Hamilton Gravel Company → NO. 1 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

- **operator_operates_mine:** West Point Gravel Company → NO. 1 PIT; 1950-01-01 to 1978-08-31; source msha-controller-operator-history
- **controller_controls_mine:** West Point Gravel Company → NO. 1 PIT; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** West Point Gravel Company → West Point Gravel Company; 1950-01-01 to 1978-08-31; source msha-controller-operator-history
- **operator_operates_mine:** Hamilton Gravel Company → NO. 1 PIT; 1978-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** John  Cockerham Jr  et al → NO. 1 PIT; 1978-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** John  Cockerham Jr  et al → Hamilton Gravel Company; 1978-09-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Philip  Cockerham  et al → Hamilton Gravel Company; 1978-09-01 to current/open; source msha-controller-operator-history