By Potipher Tembo
BWANA Mkubwa Mine has continued to be one of the oldest mines in Zambia which has resisted permanent closure.
Being a land-locked but a land-linked country, Zambia has from time immemorial depended on mining, especially copper mining, to manage her economy.
The country has for many years seen itself discovering more new mines while some of the old ones have been closing and reopening resulting in many people losing employment.
Some of the mines have been closed due to low copper prices on the world market while others have done so because of the depleting reserves.
A number of the mines that had been closed had later reopened after the prices of the metal had improved.
Bwana Mkubwa Mine has stood the test of time and has seen itself closing and reopening due to varying reasons.
Situated in Ndola on the Copperbelt, history has it that Bwana Mkubwa was pegged in 1902 in the name of Rhodesia Copper Company, and was worked by ‘ancients’.
During the period 1903-1905, four Shafts were sunk on the line of the out crop and development commenced but work was halted until the railway reached Bwana Mkubwa in 1909.
The Bwana Mkubwa Copper Mining Company was formed in 1910 and during that year No 3 Shaft was deepened to 350 ft. level and development on the 100 ft. and 250 ft. levels was completed.
Stoping started the following year and Shaft sinking was continued until at a depth of 520 ft., water was encountered and the Shaft was lost to the 350 ft. level.
In 1912, the erection of a 90 ton per day concentrator commenced and was completed in 1913, when milling operations stared.
The following year saw the cessation of operations again, on account of the drop in copper price.
Stoping and milling operations re-started in 1916 and ran until 1918 when the company entered into agreement with the Mineral Separation Company to erect a new plant, based on the Perkins process, which was essentially a cupric ammonium carbonate leach.
In 1924, open pit mining commenced, and two years later, the new metallurgical plant, rated at 1,000 tons per day, was commissioned and operated until 1931.
Several factors contributed to the decision to close Bwana Mkubwa in 1931, the main ones being the drop in copper price, the higher than budgeted metallurgical costs and the lower ore grade to mill.
In addition to these, the Nkana claims had been acquired and it was considered that, not only was the potential here far greater, but also that the metallurgical treatment of disseminated sulphide ores was both cheaper and easier. Over 40 years elapsed before operations resumed.
After re-opening in 1968, Bwana Mkubwa went under again in 1984 owing to uneconomical operations.
In 1998, Bwana Mkubwa was sold to First Quantum Minerals (FQM) under the government’s Privatisation Programme.
The open cast mining site was abandoned by the Zambia Consolidated Copper Mines (ZCCM) in 1984 when it became economically not viable for continued operation. This was the third effective closure since the open cast mine was first opened.
By 1984, the ore at the bottom of the pits could not be extracted profitably because difficulties, including water-logging, had made water extraction an increased cost for the mine.
FQM acquired the concession at Bwana Mkubwa after applying to government for the renewal of the mining licence which ZCCM had allowed to lapse when they abandoned the mine.
After acquiring the lease on the mine, FQM inherited what is known as as a ‘green field’, which refers to an inactive mining site where operations have ceased and green vegetation has taken over the site.
What was of interest to FQM were the huge tailing dumps or heaps of copper ore rock which has been worked on and has had a certain level of its copper content extracted.
FQM’s objective was to re-work these dumps in order to extract the remaining amounts of copper from these tailing dumps.
FQM put an investment of 30 million dollars in Bwana Mkubwa project for the construction of the tailing treatment plant and the sulphuric acid plant.
Indeed, Bwana Mkubwa has stood the test of time and continues to live on despite the many challenges the mine has been facing over the years.