|
US2044628A
|
|
Treating coal, ore, grain, and similar materials
|
|
US2009273A
|
|
Apparatus for dry cleaning of coal
|
|
US1789252A
|
|
Airplane and propeller
|
|
US1888636A
|
|
Screening and concentrating apparatus
|
|
US1693861A
|
|
Apparatus for cleaning coal
|
|
US1667331A
|
|
Cleaning and sizing apparatus
|
|
US1735974A
|
|
Roof support
|
|
US1687306A
|
|
Mining machine
|
|
US1687949A
|
|
Heading machine
|
|
US1634434A
|
|
Mining-machine tool
|
|
US1683297A
|
|
Mining machine
|
|
US1638507A
|
|
Mining and loading machine
|
|
US1588987A
|
|
Method of mining
|
|
US1583992A
|
|
Mining machine
|
|
US1737327A
|
|
Mining machine
|
|
US1534463A
|
|
Longwall mining machine
|
|
US1617688A
|
|
Rotary screen
|
|
US1561481A
|
|
Longwall mining machine
|
|
US1517095A
|
|
Mining apparatus
|
|
US1581686A
|
|
Screen
|
