Implementations of the accessory and associated methods allow for excavation of a ditch, wherein rotating grating means are used for expelling rubble and form a ditch. The accessory includes grating means which are moved with respect to the ditch to ensure contacting of the grating means with the road and alignment of a rotation axis of the grating means with the ditch axis. The ditch is progressively excavated when the grating means are rotated and displaced along the ditch axis. The grating means may be connectable to a mobile device through an arm assembly configured to controllably move the grating means from the mobile device. The accessory may be used for connection to a mining device for excavating the ditch along the road of an underground mining tunnel.