# Relationship history for MSHA mine 3602777

Current hierarchy: **Darrell G  Spencer → Shale Hill Coal Company Inc → Erhard #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:** Shale Hill Coal Company Inc → Erhard #1; 1950-01-01 to 1987-10-28; source msha-controller-operator-history
- **controller_controls_mine:** Danvir Edward → Erhard #1; 1950-01-01 to 1987-10-28; source msha-controller-operator-history
- **controller_controls_operator:** Danvir Edward → Shale Hill Coal Company Inc; 1950-01-01 to 1987-10-28; source msha-controller-operator-history
- **operator_operates_mine:** Shale Hill Coal Company Inc → Erhard #1; 1987-10-29 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Darrell G  Spencer et al → Erhard #1; 1987-10-29 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Darrell G  Spencer et al → Shale Hill Coal Company Inc; 1987-10-29 to current/open; source msha-controller-operator-history