# Relationship history for MSHA mine 4102282

Current hierarchy: **Dresser Industries Inc; Halliburton Co → M-I Drilling Fluids Company → Houston Barite Plant**

- 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:** Nova Pressure Services → Houston Barite Plant; 1950-01-01 to 1987-01-19; source msha-controller-operator-history
- **controller_controls_mine:** Nova Pressure Services → Houston Barite Plant; 1950-01-01 to 1987-01-19; source msha-controller-operator-history
- **controller_controls_operator:** Nova Pressure Services → Nova Pressure Services; 1950-01-01 to 1987-01-19; source msha-controller-operator-history
- **controller_controls_mine:** Halliburton Co et al → Houston Barite Plant; 1987-01-19 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** M-I Drilling Fluids Company → Houston Barite Plant; 1987-01-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Halliburton Co et al → M-I Drilling Fluids Company; 1987-01-20 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Dresser Industries Inc et al → M-I Drilling Fluids Company; 1987-01-20 to current/open; source msha-controller-operator-history