# Relationship history for MSHA mine 1509310

Current hierarchy: **Cox Ronnie L & N Charles Ross → Becky Knob Coal Company → No 1 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **operator_operates_mine:** Oak Field Branch Coal Company → No 1 Mine; 1975-08-01 to 1976-04-06; source msha-controller-operator-history
- **controller_controls_mine:** Oak Field Branch Coal Company → No 1 Mine; 1975-08-01 to 1976-04-06; source msha-controller-operator-history
- **controller_controls_operator:** Oak Field Branch Coal Company → Oak Field Branch Coal Company; 1975-08-01 to 1976-04-06; source msha-controller-operator-history
- **controller_controls_mine:** Cox Ronnie L & N Charles Ross → No 1 Mine; 1976-04-02 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Becky Knob Coal Company → No 1 Mine; 1976-04-07 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Cox Ronnie L & N Charles Ross → Becky Knob Coal Company; 1976-04-07 to current/open; source msha-controller-operator-history