Public holidays in Rhodesia weekend". Shangani Day was replaced as a public holiday by Occupation Day in 1920, but continued to be unofficially marked thereafter. Occupation Day, held on 12 September each year, marked the anniversary of the arrival of the Pioneer Column at Fort Salisbury in 1890, and their raising of the Union Jack on the kopje overlooking the site. It was renamed Pioneers' Day in 1961. Southern Rhodesia effectively became the entirety of Rhodesia in 1964 when Northern Rhodesia became independent as Zambia. After Southern Rhodesia's colonial government unilaterally declared independence from Britain on 11 November 1965, the anniversary became celebrated as
Northern Rhodesia to justify the capital cost of building a railway to the coast, but expeditions between 1899 and 1901 proved their value. Copper deposits found in Northern Rhodesia before the First World War proved uneconomic to develop. In 1906 Union Minière du Haut Katanga was formed to exploit the Katanga mines. King Leopold wanted a railway entirely in Congolese territory, linked to the Congo River, but in 1908, he agreed with the British South Africa Company to continue the Rhodesian railway to Elizabethville and the mines. Between 1912, when full-scale copper production began, until 1928 when a Congolese line was completed,