# Relationship history for MSHA mine 3602053

Current hierarchy: **David S  Himmelberger → R & D Coal Co. Inc. → R & D Coal Co. Inc.**

- 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:** Marlin Zimmerman Coal Company → R & D Coal Co. Inc.; 1950-01-01 to 1986-05-04; source msha-controller-operator-history
- **controller_controls_mine:** Marlin  Zimmerman → R & D Coal Co. Inc.; 1950-01-01 to 1986-05-04; source msha-controller-operator-history
- **controller_controls_operator:** Marlin  Zimmerman → Marlin Zimmerman Coal Company; 1950-01-01 to 1986-05-04; source msha-controller-operator-history
- **operator_operates_mine:** Buck Mountain Coal Company No 2 → R & D Coal Co. Inc.; 1986-05-05 to 1993-04-13; source msha-controller-operator-history
- **controller_controls_mine:** David  Zimmerman et al → R & D Coal Co. Inc.; 1986-05-05 to 1993-04-13; source msha-controller-operator-history
- **controller_controls_operator:** David  Zimmerman et al → Buck Mountain Coal Company No 2; 1986-05-05 to 1993-04-13; source msha-controller-operator-history
- **operator_operates_mine:** Buck Mountain Coal Company No 2 → R & D Coal Co. Inc.; 1993-04-14 to 1995-01-12; source msha-controller-operator-history
- **controller_controls_mine:** Oscar  Blough Jr → R & D Coal Co. Inc.; 1993-04-14 to 1995-01-12; source msha-controller-operator-history
- **controller_controls_operator:** Oscar  Blough Jr → Buck Mountain Coal Company No 2; 1993-04-14 to 1995-01-12; source msha-controller-operator-history
- **operator_operates_mine:** R & D Coal Co. Inc. → R & D Coal Co. Inc.; 1995-01-13 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** David S  Himmelberger et al → R & D Coal Co. Inc.; 1995-01-13 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** David S  Himmelberger et al → R & D Coal Co. Inc.; 1995-01-13 to current/open; source msha-controller-operator-history