 By 1899 , the sandstone shaft marker placed by Chandler Robbins in 1875 had been disturbed and broken , so it was replaced with a new stone by two U.S. Surveyors , Hubert D. Page and James M. Lentz . In 1912 , a simple cement pad was poured around the marker . The first modern Navajo government convened in 1923 in an effort to organize and regulate an increasing amount of oil exploration activities on Navajo lands , and they would play a big role in the monument 's further development . In 1931 , Everett H. Kimmell , another U.S. Surveyor , found this newer stone had broken too and he replaced it with a brass disc marker set in cement . In 1962 , the Bureau of Land Management and the Bureau of Indian Affairs poured an elevated cement pad around the 1931 brass marker ; this pad included the state border lines and names in tile . The monument was completely rebuilt in 1992 , and the 1931 brass marker was replaced with a disc shaped aluminum @-@ bronze plate set in granite . The monument was again rebuilt in 2010 , although the disc shaped plate from 1992 remained in place . 
