No. While mining (diamonds, gold, platinum, copper, coal) is critically important for export earnings and GDP in several Southern African countries (South Africa, Botswana, Zambia, DRC, Zimbabwe, Namibia), it is not the most common economic activity by employment.
Agriculture (subsistence and commercial) employs the largest share of the labor force across the region—estimated 50–60% of total employment in SADC countries. Most rural households rely on crop cultivation (maize, cassava, sorghum, tobacco, cotton) and livestock for livelihoods.
Mining's outsized economic footprint (foreign exchange, fiscal revenue, infrastructure) often creates a perception of dominance, but in terms of how most people make a living, farming remains the primary activity.