▁death s ▁from ▁early ▁cave ▁expl oration , ▁there ▁has ▁been ▁at ▁least ▁one ▁serious ▁injury ▁in ▁ 1 9 7 4 ▁which ▁resulted ▁in ▁a ▁six - hour - long ▁rescue . ▁ ▁Black ▁Ch asm ▁Ca vern ▁has ▁passed ▁through ▁various ▁own ers , ▁including ▁O w ens ▁Illinois ▁C ement ▁Co ., ▁American ▁C ement ▁Co ., ▁and , ▁currently , ▁Sierra ▁Nev ada ▁Rec re ation ▁Corporation ▁( SN RC ). ▁Black ▁Ch asm ▁was ▁selected ▁for ▁consideration ▁as ▁a ▁National ▁Natural ▁Land mark ▁( NN L ) ▁in ▁ 1 9 7 5 ▁after ▁National ▁Park ▁Service ▁personnel ▁entered ▁into ▁the ▁cave ▁and ▁saw ▁the ▁hel ict ite ▁cry stal ▁display ▁in ▁the ▁Land mark ▁Room . ▁The ▁park ▁service ▁personnel ▁described ▁Black ▁Ch asm ▁as ▁having , ▁" The ▁best ▁hel ict ites ▁in ▁the ▁west ." . ▁At ▁the ▁time , ▁Black ▁Ch asm ▁was ▁sl ated ▁to ▁be ▁quar ried , ▁as ▁an ▁open ▁pit ▁mine , ▁for ▁the ▁gra vel ▁that ▁the ▁bed rock ▁would ▁provide . ▁The ▁quar ry ▁company ▁who ▁owned ▁the ▁land ▁was ▁aware ▁of ▁the ▁cave , ▁but ▁not ▁of ▁its ▁rare ▁display ▁of ▁hel ict ites . ▁After ▁the ▁N NL ▁status ▁was ▁granted ▁in ▁January ▁ 1 9 7 6 , ▁the ▁quar ry ▁company ▁still ▁had ▁legal ▁rights ▁to ▁quar ry ▁the ▁property , ▁but ▁there ▁was ▁a ▁moral ▁oblig ation ▁placed ▁on ▁the ▁land own ers ▁to ▁preserve ▁the ▁cave ▁in ▁order ▁to ▁retain ▁its ▁N