Abstract: A core barrel head assembly having a longitudinal axis can comprise an elongate tube body having an outer surface, an interior cavity, a proximal end, and a distal end. The elongate tube body can define a helical groove that extends from the interior cavity to the outer surface of the elongate tube body. The helical groove can be configured to allow the elongate tube body to elastically extend and compress. The elongate tube body can define at least one aperture that extends between the interior cavity and the outer surface. The core barrel head assembly can further comprise a valve body that is attached to the elongate tube body and is movable with respect to the proximal end of the elongate tube along the longitudinal axis, as the elongate tube body compresses. When sufficiently compressed, the valve body restricts flow through the at least one aperture.

Abstract: An overshot assembly can include a distal body portion. The distal body portion can have a central axis, a length along the central axis, and an outer surface. An outer surface of the distal body portion can define, along at least a portion of the length, at least one drill string engagement portion having a first radial distance from the central axis of the distal body portion. The drill string engagement portion(s) can be configured to bias against and slide along an inner surface of a drill string. At least one recessed portion can be inwardly spaced from said first radial distance from the central axis. The recessed portion(s) can each be configured to cooperate with the inner surface of the drill string to define a respective flow path along the length of the distal body portion.

Abstract: A drill rod can include a body having an outer surface, an inner surface, a longitudinal axis aligned with a drilling axis, and at least one longitudinally extending groove extending radially outwardly from the longitudinal axis relative to the inner surface. The inner surface and the at least one longitudinally extending groove can cooperate to define an interior space through which an inner assembly can be received as the inner assembly is advanced and retracted relative to the drilling axis. The at least one longitudinally extending groove of the body of the drill rod can be configured to permit axial flow of fluid through the drill rod as portions of the inner assembly engage the inner surface of the body of the drill rod.

Abstract: A drill rod can include a body having an outer surface, an inner surface, a longitudinal axis aligned with a drilling axis, and at least one longitudinally extending groove extending radially outwardly from the longitudinal axis relative to the inner surface. The inner surface and the at least one longitudinally extending groove can cooperate to define an interior space through which an inner assembly can be received as the inner assembly is advanced and retracted relative to the drilling axis. The at least one longitudinally extending groove of the body of the drill rod can be configured to permit axial flow of fluid through the drill rod as portions of the inner assembly engage the inner surface of the body of the drill rod.