# Relationship history for MSHA mine 0201898

Current hierarchy: **Grey Duane → Ozark Sand & Rock → Ozark Sand And Rock**

- 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:** Central Sand & Rock Company → Ozark Sand And Rock; 1978-03-09 to 1979-02-16; source msha-controller-operator-history
- **controller_controls_mine:** Farmer Morris S → Ozark Sand And Rock; 1978-03-09 to 1979-02-16; source msha-controller-operator-history
- **controller_controls_operator:** Farmer Morris S → Central Sand & Rock Company; 1978-03-09 to 1979-02-16; source msha-controller-operator-history
- **operator_operates_mine:** Mutual Mining & Materials → Ozark Sand And Rock; 1979-02-17 to 1979-06-30; source msha-controller-operator-history
- **controller_controls_mine:** Knox R J → Ozark Sand And Rock; 1979-02-17 to 1979-06-30; source msha-controller-operator-history
- **controller_controls_operator:** Knox R J → Mutual Mining & Materials; 1979-02-17 to 1979-06-30; source msha-controller-operator-history
- **operator_operates_mine:** Farmers Sand & Rock Company → Ozark Sand And Rock; 1979-07-01 to 1982-11-29; source msha-controller-operator-history
- **controller_controls_mine:** Farmer Morris S → Ozark Sand And Rock; 1979-07-01 to 1982-11-29; source msha-controller-operator-history
- **controller_controls_operator:** Farmer Morris S → Farmers Sand & Rock Company; 1979-07-01 to 1982-11-29; source msha-controller-operator-history
- **operator_operates_mine:** Ozark Sand & Rock → Ozark Sand And Rock; 1982-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Grey Duane → Ozark Sand And Rock; 1982-11-30 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Grey Duane → Ozark Sand & Rock; 1982-11-30 to current/open; source msha-controller-operator-history