# Relationship history for MSHA mine 1512888

Current hierarchy: **Robert C  Gregory Sr. → Cross Over Mining Company Inc → Kellioka No 1**

- 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:** Tracer Coal Inc → Kellioka No 1; 1981-05-01 to 1982-08-22; source msha-controller-operator-history
- **controller_controls_mine:** Brock Rick → Kellioka No 1; 1981-05-01 to 1982-08-22; source msha-controller-operator-history
- **controller_controls_operator:** Brock Rick → Tracer Coal Inc; 1981-05-01 to 1982-08-22; source msha-controller-operator-history
- **operator_operates_mine:** Saylor & Bargo Mining Company → Kellioka No 1; 1982-08-23 to 1983-03-30; source msha-controller-operator-history
- **controller_controls_mine:** Saylor Frank & Royal Bargo → Kellioka No 1; 1982-08-23 to 1983-03-30; source msha-controller-operator-history
- **controller_controls_operator:** Saylor Frank & Royal Bargo → Saylor & Bargo Mining Company; 1982-08-23 to 1983-03-30; source msha-controller-operator-history
- **operator_operates_mine:** Cross Over Mining Company Inc → Kellioka No 1; 1983-03-31 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Robert C  Gregory Sr. → Kellioka No 1; 1983-03-31 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Robert C  Gregory Sr. → Cross Over Mining Company Inc; 1983-03-31 to current/open; source msha-controller-operator-history