Density of Azurite - Standard Deviation - Chemistry Assignment

Question 1  
Consider a goethite ore assaying around 2196 which needs to be routinely sampling to a confidence level of ±0.296. Fe 92 times out of 100. Pyrite is liberated as a particle size of 300 microns. Calculate the mass of the sample required to be collected if the maximum particle size is 3.5min. 
 

Question 2 
Regular samples were required of the feed to a copper processing plant, having a copper content of about 796. The confidence level of estimation was required to be 0.196 Cu at 2s standard deviation. The liberation size of the Cu mineral (azurite) In the ore was determined to be 85 um. The top size of the ore from the sampler was 3.5 cm. Determine the minimum mass of sample required to represent the ore. Given; the density of azurite Is 3770 kg/m' and the density of the gangue is 2500 kg/m'. 
 

Question 3 
Consider a lead ore assaying around 596 Pb, which needs to be routinely sampled to a confidence level of 10.1% Pb, 95 times out of 100. The galena is liberated from the quartz gangue at a particle size of ISOpm. 
 

Question 4 
Iron ore was sampled before stockpiling with a stacker. One hundred samples taken from the stacker-conveyor showed a standard deviation in the iron assay of 0.5 96. The ore assayed, on average, 55 96 Fe. Sieve analysis of the samples showed that the largest size was less than 9mm and the liberation of Fe was maximum in the sin range, -400 + 300 microns. Given that the specific gravity of the ore was 5.4 and the specific gravity of the gangue vvas 2.6, estimate the minimum mass of sample required representing the stack.