# Relationship history for MSHA mine 0101856

Current hierarchy: **Markham J M → Gem Coal Inc → Gem Strip**

- 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:** Gem Coal Inc → Gem Strip; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Markham J M → Gem Strip; 1978-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Markham J M → Gem Coal Inc; 1978-04-01 to current/open; source msha-controller-operator-history