# Relationship history for MSHA mine 4801203

Current hierarchy: **Ron  McMurry → McMurry Ready Mix Co. → Crusher #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

- **controller_controls_mine:** Ron  McMurry  et al → Crusher #1; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Rissler & Mc Murry Company → Crusher #1; 1978-12-01 to 2004-11-22; source msha-controller-operator-history
- **controller_controls_operator:** Ron  McMurry  et al → Rissler & Mc Murry Company; 1978-12-01 to 2004-11-22; source msha-controller-operator-history
- **operator_operates_mine:** McMurry Ready Mix Co. → Crusher #1; 2004-11-23 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Ron  McMurry  et al → Crusher #1; 2004-11-23 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Ron  McMurry  et al → McMurry Ready Mix Co.; 2004-11-23 to current/open; source msha-controller-operator-history