Drilling is the best way to examine the subsurface facies.  Drilling is most commonly employed :

Drilling activities handle and monitor by operations geologist and experienced drilling operator.
Operations geologist will guide the drilling and monitor the lithology and coals.
Experienced drilling operator has a role in operating the drilling unit, coal estimation by drilling and beware of some kinds of unexpected lithology which can be harmful for the drilling.

Drill Machine
Depth Capacity
Drilling Inclination
Hole Size
Drill Move Type
Drilling Type
Mustang 9-F4
± 300 m
-5° ~ 120°
Crawler Type
Open hole drilling
Touch coring
Full coring
Standard Penetration Test
Horizontal drilling
Ground Water Level drilling
Jacro 200
± 180 m
0° ~ 90°
Skid Type
Jacro 500
± 400 m
0° ~ 90°
Skid Type

Open hole or chip drilling is achieved by a variety of rotary drilling techniques and either air or fluid circulation (water or drilling mud) to generate incremental chip or cuttings samples of the interval drilled. For every 1m drilled, a representative sample of the recovered drill chips or cuttings should be collected by the drill crew and laid out in core box.

Consequently all chip boreholes should be geophysically logged. This geophysical log is used to confirm the depth and thickness of significant lithological intervals. Every coal seam should be adjusted using the geophysical log response and gross lithology of cutting data.

Core drilling (Coring) used to obtain representative samples for geotechnical, coal quality and other testing to provide as much information from a borehole as possible.

Coring divided into 2 drilling methods, Full coring and Touch coring. Full coring is a core drilling which obtain core sample from drilling surface until reaching target depth and Touch coring is a combination drilling methods between Open hole drilling and core drilling execute once in a bore hole. Touch coring used to reach the coal target or rock samples from defined depth target.

Usually geotechnical drilling used Full coring methods.
Consequently, geotechnical sampling (core samples) needs to be done at the drill site.

Geotechnical samples should be received by laboratory as quickly as possible and in a physical and mechanical condition that best approximates their condition the instant the core barrel was opened. Ensure geotechnical samples are securely wrapped and packaged to prevent breakage during transport to the laboratory (CoalLog, 2015).

Standard Penetration Test (SPT) is an in situ testing method execute together with drilling which is used to determine the geotechnical engineering properties of subsurface soils. This geotechnical engineering properties include dynamical defense of soil or to take disturbed sample within penetration methods.

SPT usually executed together with Core drilling (Coring) always be monitored by MINTEC Drilling & Survey assistant to measure and calculate the progress of the SPT drilling also take responsibility of SPT samples including covering samples up with wrap plastics and transport them as soon as possible to rock laboratory.

Ground water level test is water level measurement below land surface in a well. This groundwater level measurement in a well is frequently conducted to determine the “free” water surface.  This ground water surface measurement can be used to establish ground water direction and gradients. Static ground water level measurements represent conditions in the surrounding aquifer. This can be integrated to understand the relationships between wells in our project area. This relationship meaning is to acknowledge the water flow between wells in project area. Ground water level represents the water flow in project area. Moreover, measurements over time give a better representation of aquifer conditions.

MINTEC used Submerged pump (Groundfos pump, Type : SQ 3-105) to remove drilling water which left from a borehole before the ground water level measurement. Electronic Water Level Indicators (Solinst water level meter, Model : 101) accurately record the ground water level. These types of instruments consist of a spool of dual conductor wire, a probe attached to the end and an indicator.

Standard Operating Procedures
Working Instructions
Standard Operating Procedures
SOP/MIN/DR/003. Site preparation
SOP/MIN/DR/004. Moving of drilling unit
SOP/MIN/DR/005. Coal exploration drilling


STD/MIN/DR/001. Drilling pad
STD/MIN/DR/002. Moving of drilling unit
STD/MIN/DR/003. Core handling in core box
STD/MIN/DR/004. Touch coring mechanism

WI/MIN/DR/004. Site preparation
WI/MIN/DR/005-007. Moving of drilling unit
WI/MIN/DR/008. Drilling preparation
WI/MIN/DR/009. Open hole drilling (Mustang 9-F4)
WI/MIN/DR/010. Open hole drilling (Jacro 200)
WI/MIN/DR/011. Coring (Mustang 9-F4)
WI/MIN/DR/012. Coring (Jacro 200)
WI/MIN/DR/013. Standard Penetration Test (SPT)
WI/MIN/DR/014. Pulling out the drilling rods
WI/MIN/DR/015. Jammed rods anticipation
WI/MIN/DR/016. Reporting of rods
WI/MIN/DR/017. Reporting of bit & drilling materials

External document

SNI 4153:2008. Penetration test steps with SPT