| Summary: | This research aims to find a out a better resources estimates method by
comparing on the basis of comparison of two methods i.e the Inverse Distance
and Kriging method. The research area is located in the Bahodopi district of
Morowali at block 2D PT. Bintang Delapan Mineral area.
The topography of the area is of rolling hills and undulating hilly
morphologis. Petrography analysis shows that the bedrock is harzburgit ultramafic
rock types. Block 2D has a surface area of approximately 247,63 hectares. There
are approximately 870 drill points, where there are two groups of drilling point
intervals. Drilling point of 25 meters interval has a point to drill up to 636 and has
50 metre interval of 234 points.
The resources calculation result by means of the inverse distance method
is 10400 tons. By means of Kriging method, with 486 saprolit zone drill points,
the number of drilling points that fall into the category of cut off grade is 157
points. Prior to the Kriging result, the calculation is 9178.235 tons, while the
following analysis of the Kriging resulted in the calculation reaches 9124.715
tons. After the analysis of Kriging estimation, semivariograma value is obtained.
Influence areas of nickel spread have a length of 197.64 meters in the direction N
223.8°E, while the thickness has the greatest range of 183.27 ft to the address of
the E 9.2 ° N. Initial value of the data sample standard deviation at the point of
nickel extraction is 0.32 and after the Kriging process, the standard deviation is
0.152. The variation coefficient of Initial standard deviation is 0.242. After
Kriging analysis is carried out, it is obtained a variation of coefficient value of
0.115. For the Ni thickness, the initial standard deviation value is 1.77. And after
Kriging, the value becomes is 1.78.
The difference between the amount of nickel laterite resources kriging
estimation method with inverse distance estimation methods in the saprolite zone
because of differences in the value of a thick Ni and Ni contents of the estimation
results. In kriging weighting method is not solely based on distance, but using a
statistical correlation between samples is also a function of the distance. Kriging
method using the semivariogram represent spatial differences and values among
all pairs of data samples. In the inverse distance method, the estimate depends on
the parameter ratings (power) that is used and how many points (samples) are the
minimum and maximum are included in the estimation poin.
|
|---|