▁Future ▁plans ▁to ▁extend ▁the ▁trail ▁will ▁allow ▁guests ▁to ▁visit ▁twice ▁as ▁many ▁ch amb ers ▁as ▁are ▁currently ▁seen ▁on ▁the ▁walking ▁tour . ▁ ▁Early ▁tour ▁guests ▁purchased ▁their ▁tick ets ▁at ▁a ▁k ios k , ▁but ▁in ▁December ▁ 2 0 0 3 ▁a ▁. ▁visitor ▁center ▁was ▁opened ▁to ▁the ▁public . ▁In ▁the ▁same ▁year , ▁an ▁updated ▁survey ▁and ▁expl oration ▁took ▁place ▁in ▁the ▁cave ▁and ▁in ▁one ▁of ▁the ▁la kes . ▁Using ▁traditional ▁t ape ▁measures ▁and ▁comp ass ▁read ings , ▁as ▁well ▁as ▁using ▁a ▁las er ▁meas uring ▁device , ▁the ▁expl oration ▁team ▁survey ed ▁the ▁original ▁half ▁mile ▁of ▁cave ▁and ▁also ▁discovered ▁an ▁additional ▁half ▁mile , ▁dou bling ▁the ▁length ▁of ▁known ▁cave . ▁Total ▁survey ed ▁length ▁of ▁Black ▁Ch asm ▁is ▁, ▁and ▁the ▁overall ▁depth , ▁including ▁the ▁lake , ▁is ▁, ▁with ▁ ▁above ▁lake ▁level . ▁ ▁Black ▁Ch asm ▁Ca vern ▁currently ▁offers ▁Land mark ▁walking ▁t ours ▁for ▁all ▁ages , ▁and ▁a ▁self - gu ided ▁nature ▁hi ke ▁through ▁the ▁rock ▁Z en ▁Garden . ▁From ▁ 2 0 1 1 - 2 0 1 5 , ▁Black ▁Ch asm ▁Ca vern ▁offered ▁a ▁new ▁ 2 . 5   hour ▁expedition ▁trip , ▁called ▁the ▁Lab yr inth ▁Tour . ▁This ▁tour ▁expl ored ▁the ▁surface ▁features ▁of ▁con vol uted ▁rock ▁created ▁by ▁the ▁hyd ra ul ic ▁min ing ▁process ▁used ▁during ▁the