Method and apparatus for transporting materials in a mine

A materials transport vehicle for use in an underground mine comprising:

• a mobile vehicle frame mounted on a ground engaging traction device for propelling the transport vehicle in an underground mine,
• a boom assembly extending longitudinally on said mobile frame, said boom assembly including a boom housing having a first end and a second end,
• an extension mechanism supported by said boom housing for movement between an extended position and a retracted position to extend and retract said boom assembly,
• said extension mechanism having a first end portion connected by pivot means to said mobile frame and a second end portion extending on said mobile frame forwardly from said first end portion of said extension mechanism,
• said extension mechanism including a pair of piston cylinders positioned in said boom housing,
• said boom housing forming a divided enclosure for slidably receiving first and second cylinder housing in overlying, spaced parallel relation,
• said pair of piston cylinders including a first piston cylinder and a second piston cylinder positioned in said first and second cylinder housings respectively to position said first and second piston cylinders in overlying, spaced parallel relation in said boom housing and stabilize said first and second piston cylinders to resist lateral twisting forces applied to said boom assembly,
• said first piston cylinder and said first cylinder housing pivotally connected to said mobile frame and an extensible end of said first piston cylinder connected to said boom housing,
• said second piston cylinder connected by a pin to one end of said boom housing and having an extensible end extendable from said boom housing on said mobile frame, said extensible end of said second piston cylinder connected to said second cylinder housing to move relative to said boom housing with said extensible end, and
• said extension mechanism operable upon actuation to extend said first piston cylinder to extend said boom housing on said mobile frame and extend said extensible end of said second piston cylinder and said second cylinder housing from said boom housing to move said boom assembly from a retracted position to an extended position on said mobile frame.