The building was designed by Herbert Baker after the amalgamation of eight mining companies in April 1909, when Crown Mines Ltd was founded. The office complex included an experimental laboratory with a prominent brick chimney. In 1978 the property was taken over by Rand Mines (Pty) Ltd. It was declared a National Monument under old NMC legislation on 10 February 1989. 

Geolocation
-26° 12' 18", 27° 59' 2.4"
References
9/2/228/0096 Head Office, Provincial Heritage site
www.sahra.org.za/sahris/node/33556, National Monument
Further Reading
www.sahistory.org.za/article/discovery-gold-1884
https://www.sahistory.org.za/places/langlaagte-deep-residential-village-johannesburg