| Label | Statistics | Description |
|---|---|---|
| position |  | Unique identifying number corresponding to label on map published as Open-File Report 20010-1254. Also used in Notes field as an identifier for other operations when capacities are combined. Please note that closed facilities are not included in this rep |
| rec_id | | Record identifier without further scientific significance |
| year | | The year for which the facility capacity and activity status is valid, derived from the Minerals Yearbook. |