A blasting apparatus for fragmentation of rock by timed actuation of a plurality of explosive charges each set in a borehole in the rock, the blasting apparatus comprising: at least one blasting machine (1,50) for transmitting at least one wireless command signal (2,61,62,63); and a plurality of wireless detonator assemblies (3,51...59), at least some of which are within range to receive said at least one wireless signal (2,61,62,63) from said at least one blasting machine (1,50), each wireless detonator assembly (3,51...59) associated with a corresponding explosive charge for causing actuation thereof upon transmission of a FIRE signal by an associated blasting machine (1,50), each wireless detonator assembly (3,51...59) comprising the following components: (a) a base charge; (b) wireless signal receiving means, for receiving a wireless signal (2,61,62,63) transmitted from a blasting machine (1,50) or another wireless detonator assembly (3,51...59); the blasting apparatus being characterised in that each wireless detonator assembly further comprises: (c) wireless signal processing means for determining an action required by said wireless detonator assembly (3,51...59) in response to the wireless signal (2,61,62,63) received by (b), and whether to relay said wireless signal (2,61,62,63) to another wireless detonator assembly (3,54...59) and/or to a blasting machine (1,50); and (d) wireless signal transmitting means for relaying the wireless signal (2,61,62,63) as required by (c),whereby the wireless detonator assemblies (3,51...59) form a cross-communicating network with at least one wireless detonator assembly (3,51,52,53) being in direct wireless signal communication with said at least one blasting machine (1,50), and some wireless detonator assemblies (3,54...59) being in indirect wireless signal communication with said at least one blasting machine (1,50) via relay of wireless signals to or from said at least one blasting machine (1,50) via one or more nodes in the network, each node comprising a wireless detonator assembly (3,51...59). at least one blasting machine (1,50) for transmitting at least one wireless command signal (2,61,62,63); and a plurality of wireless detonator assemblies (3,51...59), at least some of which are within range to receive said at least one wireless signal (2,61,62,63) from said at least one blasting machine (1,50), each wireless detonator assembly (3,51...59) associated with a corresponding explosive charge for causing actuation thereof upon transmission of a FIRE signal by an associated blasting machine (1,50), each wireless detonator assembly (3,51...59) comprising the following components: (a) a base charge; (b) wireless signal receiving means, for receiving a wireless signal (2,61,62,63) transmitted from a blasting machine (1,50) or another wireless detonator assembly (3,51...59); the blasting apparatus being characterised in that each wireless detonator assembly further comprises: (c) wireless signal processing means for determining an action required by said wireless detonator assembly (3,51...59) in response to the wireless signal (2,61,62,63) received by (b), and whether to relay said wireless signal (2,61,62,63) to another wireless detonator assembly (3,54...59) and/or to a blasting machine (1,50); and (d) wireless signal transmitting means for relaying the wireless signal (2,61,62,63) as required by (c),whereby the wireless detonator assemblies (3,51...59) form a cross-communicating network with at least one wireless detonator assembly (3,51,52,53) being in direct wireless signal communication with said at least one blasting machine (1,50), and some wireless detonator assemblies (3,54...59) being in indirect wireless signal communication with said at least one blasting machine (1,50) via relay of wireless signals to or from said at least one blasting machine (1,50) via one or more nodes in the network, each node comprising a wireless detonator assembly (3,51...59). (a) a base charge; (b) wireless signal receiving means, for receiving a wireless signal (2,61,62,63) transmitted from a blasting machine (1,50) or another wireless detonator assembly (3,51...59); the blasting apparatus being characterised in that each wireless detonator assembly further comprises: (c) wireless signal processing means for determining an action required by said wireless detonator assembly (3,51...59) in response to the wireless signal (2,61,62,63) received by (b), and whether to relay said wireless signal (2,61,62,63) to another wireless detonator assembly (3,54...59) and/or to a blasting machine (1,50); and (d) wireless signal transmitting means for relaying the wireless signal (2,61,62,63) as required by (c),whereby the wireless detonator assemblies (3,51...59) form a cross-communicating network with at least one wireless detonator assembly (3,51,52,53) being in direct wireless signal communication with said at least one blasting machine (1,50), and some wireless detonator assemblies (3,54...59) being in indirect wireless signal communication with said at least one blasting machine (1,50) via relay of wireless signals to or from said at least one blasting machine (1,50) via one or more nodes in the network, each node comprising a wireless detonator assembly (3,51...59).