Abstract: A theoretical study of the lognormal distribution and the three-parameters lognormal distribution are presented. The emphasis is on the study of lognormal kriging. The lognormal kriging systems and logarithmic kriging variance are established after non-bias condition and minimum estimation variance are studied. The kriging weights λ_α are solutions to the kriging systems. The kriging estimator Z_v of each block of a deposit can be estimated. Kriging estimator is the unbiased linear estimator with minimum estimation variance. The method is illustrated application to ore reserve estimation of a iron-copper deposit.