▁the ▁sensor ▁to ▁be ▁removed ▁and ▁the ▁mine ▁to ▁be ▁deliber ately ▁triggered ▁by ▁a ▁human ▁operator . ▁When ▁triggered , ▁the ▁mine ▁function ed ▁in ▁two ▁stages ▁( see ▁diagram ). ▁▁ ▁First , ▁the ▁mine ▁was ▁fired ▁ ▁up wards ▁by ▁a ▁small ▁prop ell ant ▁charge . ▁ ▁Appro xim ately ▁a ▁half - second ▁later , ▁the ▁main ▁charge ▁det on ated ▁at ▁the ▁optim um ▁height ▁to ▁kill ▁or ▁sever ely ▁inj ure ▁anyone ▁in ▁the ▁immediate ▁area . ▁ ▁The ▁main ▁charge ▁of ▁the ▁mine ▁was ▁surrounded ▁by ▁roughly ▁ 3 6 0 ▁steel ▁balls , ▁short ▁steel ▁ro ds , ▁or ▁sc rap ▁metal ▁pieces . ▁These ▁became ▁metal ▁sh rap nel ▁that ▁sp rayed ▁hor izont ally ▁from ▁the ▁mine ▁at ▁high ▁velocity . ▁ ▁The ▁time ▁between ▁trigger ing ▁and ▁ign ition ▁of ▁the ▁prop elling ▁charge ▁varied ▁between ▁ 3 . 9 ▁and ▁ 4 . 5 ▁seconds , ▁depending ▁on ▁the ▁age ▁and ▁condition ▁of ▁the ▁mine . ▁According ▁to ▁German ▁documentation , ▁the ▁S - mine ▁was ▁le th al ▁within ▁ ▁and ▁could ▁inf lict ▁cas ual ties ▁within ▁. ▁American ▁training ▁manual s ▁war ned ▁of ▁cas ual ties ▁at ▁up ▁to ▁. ▁ ▁A ▁common ▁mis con ception ▁pre va iled ▁that ▁the ▁S - mine ▁would ▁not ▁det on ate ▁until ▁its ▁victim ▁stepped ▁off ▁the ▁trigger . ▁This ▁f alla cy ▁was ▁propag ated ▁by ▁incorrect ▁United ▁States ▁propag anda ▁during ▁World ▁War ▁II . ▁The