# Relationship history for MSHA mine 2100611

Current hierarchy: **April J Sibson; Josh V Sibson → Sibson Gravel L.L.C. → High Country Hard Rock - Williams 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: 2026-10-17T05:35:58.500035+00:00

## Valid-time edges

- **operator_operates_mine:** Sibson Gravel Company → High Country Hard Rock - Williams Pit; 1950-01-01 to 1986-08-13; source msha-controller-operator-history
- **controller_controls_mine:** Vern  Sibson → High Country Hard Rock - Williams Pit; 1950-01-01 to 1986-08-13; source msha-controller-operator-history
- **controller_controls_operator:** Vern  Sibson → Sibson Gravel Company; 1950-01-01 to 1986-08-13; source msha-controller-operator-history
- **operator_operates_mine:** Sibson Gravel LLC → High Country Hard Rock - Williams Pit; 1986-08-14 to 2018-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Clair  Sibson → High Country Hard Rock - Williams Pit; 1986-08-14 to 2014-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Clair  Sibson → Sibson Gravel LLC; 1986-08-14 to 2014-03-31; source msha-controller-operator-history
- **controller_controls_mine:** Joshua V  Sibson → High Country Hard Rock - Williams Pit; 2014-04-01 to 2021-04-08; source msha-controller-operator-history
- **controller_controls_operator:** Joshua V  Sibson → Sibson Gravel LLC; 2014-04-01 to 2018-03-31; source msha-controller-operator-history
- **operator_operates_mine:** High Country Hard Rock L.L.C. → High Country Hard Rock - Williams Pit; 2018-04-01 to 2021-04-08; source msha-controller-operator-history
- **controller_controls_mine:** Josh V Sibson et al → High Country Hard Rock - Williams Pit; 2018-04-01 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Josh V Sibson et al → High Country Hard Rock L.L.C.; 2018-04-01 to 2021-04-08; source msha-controller-operator-history
- **controller_controls_operator:** April J Sibson et al → High Country Hard Rock L.L.C.; 2018-04-01 to 2021-04-08; source msha-controller-operator-history
- **operator_operates_mine:** Sibson Gravel L.L.C. → High Country Hard Rock - Williams Pit; 2021-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Joshua V  Sibson → Sibson Gravel L.L.C.; 2021-04-09 to 2021-04-08; source msha-controller-operator-history
- **controller_controls_mine:** April J Sibson et al → High Country Hard Rock - Williams Pit; 2021-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** April J Sibson et al → Sibson Gravel LLC; 2021-04-09 to 2018-03-31; source msha-controller-operator-history
- **controller_controls_operator:** Josh V Sibson et al → Sibson Gravel LLC; 2021-04-09 to 2018-03-31; source msha-controller-operator-history
- **controller_controls_operator:** April J Sibson et al → Sibson Gravel L.L.C.; 2021-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Josh V Sibson et al → Sibson Gravel L.L.C.; 2021-04-09 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Clair  Sibson → Sibson Gravel L.L.C.; 2021-04-09 to 2014-03-31; source msha-controller-operator-history