Ntau tus neeg yuav xav tias yog vim li cas Black Mountain Pob zeb tsis tshwm sim tiag tiag -tshwj xeeb yog tom qab ua tiav. Yog vim li cas yog thaum lub sij hawm txiav thiab sib tsoo txheej txheem, lub pob zeb nto ua abraded, ua rau ib tug greyish tsos. Cov nyhuv no yog ntxiv accentuated los ntawm kev xav ntawm lub hnub ci, ua rau nws zoo dua grey. Txawm li cas los xij, thaum Black Mountain Pob zeb ntub dej, nws rov qab mus rau nws cov xim dub tob; ib zaug nws dries, nws tig grey dua.
Txhawm rau khaws qhov "ntub zoo li no," cov txheej txheem siv cov pob zeb pob tshab rau saum npoo ntawm Pob Zeb Dub. Qhov no tsis tsuas yog ua kom lub ntsej muag ntub dej dhau lub sijhawm tab sis kuj rov ua kom lub pob zeb rov qab rau nws qhov tseeb, xim ntuj. Yog li ntawd, cov pob zeb dub pob zeb ua tiav feem ntau yog kho nrog cov sealant no kom nws ua kom zoo li ntub dej.
Hauv cov ntsiab lus, kev sib cuam tshuam ntawm "ntub" thiab "qhuav" zoo nkauj ntawm Pob Zeb Dub yog ua tiav los ntawm daim ntawv thov pob zeb sealant- cov txheej txheem uas tsis tsuas yog txhim kho lub pob zeb zoo nkauj xwb tab sis kuj tso cai rau nws pom cov yam ntxwv sib txawv ntawm ntau yam ib puag ncig.
