Geochemical exploration comprises 4 steps:
step 1Collect the secondary data and study
the geology characteristic of the site
1. Sample collection planning:Sediment sampling point must cover
all site depending on:
- Size of the area
- Size of the area
- Boundary of the potential area
- Duration and budget
and specify the sampling referring to the above information.
step 2Collect geochemical sample and prepare
sample for chemical analysis
2. Sediment sampling:separate as 2 steps e.g., sample collection
and sample preparation for chemical analysis. The sample must be collected from
the active sediment area.
Present points (red dot) of sediment sampling for regional exploration, distance
of each point is about 2-5 kilometer
The collected sample must be air dry. In case of the sample is not completely dried,
it must be dried in the oven at 60 decree Celsius for 45 minutes to 1 hour and left
it cool down to room temperature. Mash the sample in a mortar (be careful to avoid
cracking of stone or mineral grain) then sieve with no. 80 mesh to get at least
200 grams of sample, mix it, and divide the sample by coning and quartering method.
Put 100 grams of sample into double layer plastic bag, label number of sample and
submit for chemical analysis. Keep the remaining as the reference.
step 3Submit sample for chemical analysis
to determine amount of elements
3. Chemical analysis:Depend on the efficiency of analytical
tools. Tool that can analyze trace elements and identify many types of element is
benefit for getting the information that can be applied efficiently.
Geochemical exploration can be analyzed as 2 types depending on budget of each project
1.analyze at Department of Mineral Resources: the sample
will be analyzed for 18 elements comprising As, Ba, Cd, Co, Cr, Cu, Fe, K, Mg, Mn,
Mo, Na, Ni, Pb, Sb, Ti, V, and Zn using ICP-OES
2.analyze by private company: the sample will be analyzed
for 34 elements comprising Ag, Al, As, Ba,
Be, Bi, Ca, Cd, Co, Cr, Cu, Fe, Hg, K, La, Li, Mg, Mn, Mo, Na, Ni, P,
Pb, S, Sb, Sc, Sn, Sr,
Ti, V, W, Y, Zn, and Zr
using ICP-MS.
step 4Evaluate the result statistically
to identify the amount of element that is unusually high and prepare the report
4. Evaluate and interpret the result:Identify background amount,
maximum of background amount, the unusual high amount, and prepare geochemical map.
- Evaluate that the area found high amount of element is significantly
or not
- Evaluate the cause of the unusual high amount
- Study factors controlling the distribution of the element
- Find the area expecting to involve with the mineral site for further
exploration
Present the example of interpretation of lead (Pb) distribution in Singburi