# Relationship history for MSHA mine 4604099

Current hierarchy: **Ward Construction Co & M & O Coal Co → Ward Coal Company → Ward Surface 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

- **operator_operates_mine:** Ward Construction Company Inc → Ward Surface Mine; 1974-02-01 to 1979-05-28; source msha-controller-operator-history
- **controller_controls_mine:** Ward Darrell E-Mark Et Al → Ward Surface Mine; 1974-02-01 to 1980-12-03; source msha-controller-operator-history
- **controller_controls_operator:** Ward Darrell E-Mark Et Al → Ward Construction Company Inc; 1974-02-01 to 1979-05-28; source msha-controller-operator-history
- **controller_controls_mine:** Ward Construction Co & M & O Coal Co → Ward Surface Mine; 1978-08-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ward Coal Company → Ward Surface Mine; 1979-05-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ward Construction Co & M & O Coal Co → Ward Coal Company; 1979-05-29 to current/open; source msha-controller-operator-history