Alex Richardson wrote a "Note on the geology of Lake Nyassa" (now Lake Malawi) that was published in the Transactions of the Institution of Mining and Metallurgy (England) for 1900/1901. In 1905 he was still an associate of that institution (AIMM), and had been elected a Fellow of the Royal Geographical Society (FRGS).
In 1902 Richardson resided in Johannesburg and by 1905 was employed as mining engineer and surveyor by the Treasury Gold Mining Company in Cleveland (Johannesburg). He became a member of the Chemical, Metallurgical and Mining Society of South Africa in 1902, was a member of the society's council from 1907, served as joint vice-president for 1912/3, and as president plus chairman of the editorial committee for 1913/4. The first paper he published in the society's Journal dealt with "Mine subsidence" (1906/7, Vol. 7, p. 279-). In October 1909 he read a paper on "The Barberton goldfield", which was also published in the Journal (1909/10, Vol. 10, p. 122-).
Richardson was a member of the South African Association for the Advancement of Science in 1903 (but no longer in 1906).