If the insurgents planned to confront the Portuguese openly, one or two heavy machine guns would be sited to sweep the ditch and other likely areas of cover. Other mines used included the PMN (Black Widow), TM-46, and POMZ. Even amphibious mines were used such as the PDM, along with numerous home-made antipersonnel wood box mines and other nonmetallic explosive devices. The impact of mining operations, in addition to causing casualties, undermined the mobility of Portuguese forces, while diverting troops and equipment from security and offensive operations to convoy protection and mine clearance missions.