# Relationship history for MSHA mine 4800282

Current hierarchy: **Marcia  Martin; Richard  Martin → Kylander Construction Company → SYNDERGUARD PIT**

- 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:** Kylander Construction Company Inc → SYNDERGUARD PIT; 1950-01-01 to 1992-08-02; source msha-controller-operator-history
- **controller_controls_mine:** Ernest M  Kylander → SYNDERGUARD PIT; 1950-01-01 to 1992-08-02; source msha-controller-operator-history
- **controller_controls_operator:** Ernest M  Kylander → Kylander Construction Company Inc; 1950-01-01 to 1992-08-02; source msha-controller-operator-history
- **operator_operates_mine:** Kylander Construction Company → SYNDERGUARD PIT; 1992-08-03 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Marcia  Martin et al → SYNDERGUARD PIT; 1992-08-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Marcia  Martin et al → Kylander Construction Company; 1992-08-03 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Richard  Martin et al → Kylander Construction Company; 1992-08-03 to current/open; source msha-controller-operator-history