Ke hoʻolauna nei i ka KJ421 Hydraulic Tunnel Boring Rig - ʻo ka hopena hope loa no kāu mau hemahema a pau. Hoʻolālā kūikawā ʻia kēia mīkini wili nui e hālāwai me nā tunnels o nā ʻano nui like ʻole, me nā ʻāpana ʻāpana mai ka 16-68 square meters. Loaʻa i ka rig drilling ka mana drilling super, hiki ke wili i nā lua blast a me nā bolts ma ke kū pololei, inclined a me nā kūlana ākea, a he mea pono loa ia no ke kūkulu ʻana i ka tunnel.