Buying lead ore, CIF China, Korea

We are interested in buying lead ore on a monthly basis. We would like to sign a contract for 12 months.
Preferrable payment terms: LC at sight only.
Quantity 5000 M.Tons 60 % up.
Please send us your offers CIF China / Korean ports including the following information:
- origin of the product;
- percentage you can offer (over 60 / 70% preferred);
- test report of the specifications;
Before shipment need pre-shipment inspection by SGS or equivalent.