# Relationship history for MSHA mine 4606170

Current hierarchy: **Westmoreland Coal Company → Elk River Sewell Coal Company → Fork Ridge Strip #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:** Ward Darrell E-Mark Et Al → Fork Ridge Strip #1; 1974-02-01 to 1980-12-03; source msha-controller-operator-history
- **controller_controls_mine:** White Richard N → Fork Ridge Strip #1; 1977-08-01 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Poval Corporation → Fork Ridge Strip #1; 1979-10-17 to 1984-12-20; source msha-controller-operator-history
- **controller_controls_mine:** Helmick Robert H → Fork Ridge Strip #1; 1980-05-01 to current/open; source msha-controller-operator-history
- **operator_operates_mine:** Ward Construction Company Inc → Fork Ridge Strip #1; 1980-06-01 to 1980-12-03; source msha-controller-operator-history
- **controller_controls_operator:** Ward Darrell E-Mark Et Al → Ward Construction Company Inc; 1980-06-01 to 1980-12-03; source msha-controller-operator-history
- **operator_operates_mine:** M L M Corp → Fork Ridge Strip #1; 1980-12-04 to 1981-08-06; source msha-controller-operator-history
- **controller_controls_operator:** White Richard N → M L M Corp; 1980-12-04 to 1981-08-06; source msha-controller-operator-history
- **operator_operates_mine:** Elk River Sewell Coal Company → Fork Ridge Strip #1; 1981-08-07 to 1981-12-02; source msha-controller-operator-history
- **controller_controls_operator:** Poval Corporation → Elk River Sewell Coal Company; 1981-08-07 to 1981-12-02; source msha-controller-operator-history
- **operator_operates_mine:** Robert H Helmick Inc → Fork Ridge Strip #1; 1981-12-03 to 1982-02-04; source msha-controller-operator-history
- **controller_controls_operator:** Helmick Robert H → Robert H Helmick Inc; 1981-12-03 to 1982-02-04; source msha-controller-operator-history
- **operator_operates_mine:** Elk River Sewell Coal Company → Fork Ridge Strip #1; 1982-02-05 to 1984-12-20; source msha-controller-operator-history
- **controller_controls_operator:** Poval Corporation → Elk River Sewell Coal Company; 1982-02-05 to 1984-12-20; source msha-controller-operator-history
- **operator_operates_mine:** Elk River Sewell Coal Company → Fork Ridge Strip #1; 1984-12-21 to current/open; source msha-controller-operator-history
- **controller_controls_mine:** Westmoreland Coal Company → Fork Ridge Strip #1; 1984-12-21 to current/open; source msha-controller-operator-history
- **controller_controls_operator:** Westmoreland Coal Company → Elk River Sewell Coal Company; 1984-12-21 to current/open; source msha-controller-operator-history