the zinc price is important, here: http://www.kitcometals.com/ check 'charts' for historic prices & stock levels
producing & selling zinc generally incurs a 'smelter charge' of 20% to 30% of the revenue
for example, if the zinc market price is $1/lb, the miner might receive 75 cents/lb
many large zinc projects (eg. IBG) have low grade zinc (eg. 5% grade)
a good zinc grade probably starts at about 8% to 10% grade
CZL are targeting 25% grade zinc however the zinc lenses are very narrow, say 5 metre average
CZL have the mining infrastructure basically in place. therefore, it is the low CAPEX nature of CZL that makes it attractive
CZL could be mining zinc next year
if they did not already have a processing plant (upgrade needed) and tunnels in place, it may not be attractive due to the relatively narrow & deep lenses (shoots) of zinc