Abstract. Pyrethrum (Tanacetum cineraiifolium) is a perennial plant in the family of Asteraceae which is cultivated for the production of six closely related esters called pyrethrins, which possess insecticidal properties. Pyrethrins can be separated into two groups of three ester compounds: pyrethrin I and II. The pyrethrin I fraction contains chrysanthemic acid products, including pyrethrin I, cinerin I, and jasmolin I. The pyrethrin II fraction is derived from pyrethric acid made up of pyrethrin II, cinerin II, and jasmolin II. Using natural pesticide may lead to organic farming, and advantage of organic farming is more beneficial to biodiversity and the environment, and of course organic produce reduces dietary exposure to pesticides. Organic farmers can use pyrethrins as an insecticide for fruit and vegetable crops. Easily degraded by oxygen, light and temperature, pyrethrum compounds are environmentally friendly and compatible with organic farming.

Samples of the waste rock obtained from Marofeng ground 60, 70 and 80% passing 75 were leached with cyanide in bottle roll tests. The results obtained showed that the percentage of of gold dissolution did not increase directly with increasing concentration of cyanide in the leachant with the highest average dissolution percents of 88.75, 94.34 and 95.90% found at 600, 500 and 500 ppm, for 60, 70 and 80% passing sizes, respectively. It was also noted that the lowest average percents cyanide consumption of 62.91, 61.73 and 58.56 at 60, 70 and 80% passing 75 µm were obtained at the 500 ppm cyanide concentrations. It was further observed that a clear pattern of increasing lime content with increasing cyanide concentration was only observed at the 70% grind size, with the least lime content of 150.37 ppm at 500 ppm cyanide higher than the least lime contents for the 60 and 80% grind sizes. The results obtained thus suggest the 70% grind passing 75 µm ore with the lowest lime and moderate power consumption a good choice for the leaching of the waste rock.