Men of Men by Wilbur Smith

It was the epoch of empire, the age of pride and blood and conquest, the time of Rhodes and Jameson striking north from the Cape in search of gold and diamonds, land and glory.
Such a man was Zouga Ballentyne whose epic journey from the danger and drudgery of the Kimberley mines to the rich grasslands below the Zambezi follows a bloodstained road where the death of a kind and the destruction of a warrior nation are the price of empire...