| Year | Operation Name | Number | Type | Opening | District | City | County | Company Name | Railroad Shipments (tons) | Railroad to Mine | Truck Shipments (tons) | Total Production (tons) | Days Worked | Employees | Notes |
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| 1918 | Dennington | | Washery | | 7 | | Lackawanna | Dennington Coal Co. | 32,126 | Erie | 0 | 32,126 | 117 | 18 | | | 1919 | Dennington | | Washery | | 7 | | Lackawanna | Dennington Coal Co. | 7,587 | Erie | 0 | 7,587 | 22 | 22 | | | 1920 | Dennington | | Washery | | 7 | | Lackawanna | Dennington Coal Co. | 37,547 | DL&W | 0 | 37,547 | 137 | 27 | | | 1921 | Dennington | | Washery | | 7 | | Lackawanna | Dennington Coal Co. | 0 | DL&W | 0 | 0 | | | Idle. | | 1922 | Dennington | | Washery | | 7 | | Lackawanna | Dennington Coal Co. | 23,734 | DL&W / Erie | 0 | 23,734 | 135 | 23 | | | 1923 | Dennington | | Washery | | 7 | | Lackawanna | Dennington Coal Co. | 27,743 | DL&W / Erie | 0 | 27,743 | 176 | 20 | | | 1926 | Dennington | | Washery | | 7 | | Lackawanna | Dennington Coal Co. | 2,940 | | 0 | 2,940 | 30 | 18 | |
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