# Relationship history for MSHA mine 1511704

Current hierarchy: **Timothy P  Smith → American Engineering & Construction → Pyro Prep 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: 2026-10-13T11:19:05.459773+00:00

## Valid-time edges

- **controller_controls_mine:** Costain Group PLC → Pyro Prep Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Pyro Energy Corp → Pyro Prep Plant; 1950-01-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Pyro Mining Company → Pyro Prep Plant; 1978-12-01 to 1982-01-24; source msha-controller-operator-history
- **controller_controls_operator:** Pyro Energy Corp → Pyro Mining Company; 1978-12-01 to 1982-01-24; source msha-controller-operator-history
- **operator_operates_mine:** Costain Coal Inc → Pyro Prep Plant; 1982-01-25 to 1997-07-20; source msha-controller-operator-history
- **controller_controls_operator:** Costain Group PLC → Costain Coal Inc; 1982-01-25 to 1997-07-20; source msha-controller-operator-history
- **controller_controls_mine:** Iracoal Incorporated → Pyro Prep Plant; 1997-01-31 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Lodestar Energy Incorporated → Pyro Prep Plant; 1997-07-21 to 2003-07-23; source msha-controller-operator-history
- **controller_controls_operator:** Iracoal Incorporated → Lodestar Energy Incorporated; 1997-07-21 to 2003-07-23; source msha-controller-operator-history
- **operator_operates_mine:** American Engineering & Construction → Pyro Prep Plant; 2003-07-24 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Timothy P  Smith → Pyro Prep Plant; 2003-07-24 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Timothy P  Smith → American Engineering & Construction; 2003-07-24 to current/open; source msha-controller-operator-history