1School of Natural Resources, Copperbelt University, Kitwe, Zambia Ecological restoration of mining generated wastelands using biochar technology: A potential contribution to sustainable mining in Zambia 1Stephen Syampungani, 2Olusegun Yerokun, 1Concilia Monde 1Wilson Moono, Nancy Chileshe & Nalukui Matakala 1School of Natural Resources, Copperbelt University, Kitwe, Zambia 2Zambia Open University, Lusaka

Preparation for mining Primary forest/woodland Tailings dam/Wasteland Degraded site Preparation for mining Primary forest/woodland ? Tailings dam/Wasteland Stunted vegetation

Background Zambia has a mining history spanning over 90 years Largest copper deposits in Africa_Zambia 6% of known copper reserves globally 48% Zambia not geologically surveyed Global consumption & demand for most of the minerals_Projected increase Positive More employment/jobs??? Massive infrastructure More money??? Massive ecological foot print: Through generation of wastelands:i) wasterocks, ii) overburden materials & iii) tailings

Background: Some issues Mining generated wastelands: An environmental problem & wastage of land For example, Copperbelt alone 9,125 ha of wasteland contains 791 million tons of tailings and 20,146 ha Contain 1,899 million tons of overburden materials Additional 388 & 279 ha contain 77 million tons & 40 millions of wasterock and slag respectively

Background: Some issues Mining industry expanding in the recent past New deposits of copper and other minerals such nickel, coal being discovered in many parts of the country; Northwestern, Central & Southern Provinces More areas will be affected as need for more dumping ground will increase_ More mining generated wastelands

Background: some issues More and more generated wastelands remain un-vegetated /poor /stunted vegetation for many years Poor vegetation Limited woody plants i) High toxicity arising from heavy metals ii) Surface and ground water contamination

Background: Concepts Attempts to re-vegetate wastelands has recorded more failures Recorded success: Species selection based on ability to grow and adaptation Not ability to immobilize heavy metals No classification of species into classes based on functional traits Excluders And accumulators Therefore, postponement of environmental problem_approach

Approach in biochar technology application Determination of heavy metal concentration Cu, Co,Ba, Ni, As,Zn, Pd, Cr, V, Cd & physical properties CU= 12,237.33±1746.87mg/kg (Tailing samples ) 7411.67±1317.53mg/kg (Overburden samples) Cd=0.60±0.23mg/kg and 0.25±0.13mg/kg on tailings and overburden material, Pollution load factor= 8.97 and 5.84 on the tailings and overburden material, respectively Acidity (mean pH) = 6.0 and 4.7 for the tailings and overburden material, respectively

The sites have high pollution load index And are high contaminated Conclusion The sites have high pollution load index And are high contaminated Very low porosity and no humus The need for soil amendment biochar technology that enhance heavy metal immobilization

Reduced leaching on nitrogen Increased CEC in the soil Moderation of soil acidity Increased water holding capacity Increased number of soil beneficial biota Heavy metal immobilization & sequesteration

Biochar sources and soil amendments Biochar is partially corbonized organic waste: Wood chips Sawdust (100,000 m3 Corncobs Chicken manure Various proportions of biochar and effect on soil are being studied

BIOCHAR TECHNOLOGY AND SPECIES CLASSIFICATION Biochar technology to be enhanced by classification of species: Accumulators/hyperaccumulators Excluders

Accumulators vs excluders Accumulars= absorbs metals and tend to accumulate heavy metals When dead heavy metals flows back into the ecosystem Excluders Exclude heavy metals from being absorbed Immobilize & sequester them

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