(INTERNAL USED)

GUIDELINES OF DAILY

GEOTECHNICAL INSPECTION PIT

AS A ONE OF DAILY MONITORING

SITE PROGRAM

MUH ARIF IDHAM

ENGINEER GEOLOGIST SITE PT.PIK

FOCUS OF REPORT :

Checklist daily inspection and descriptions

Term Risk With Control

Action Implemented

Geotechnical Inspection Program

Introduction

This report arranged as a reference in daily

geotech monitoring program. As a first data

inspection pit daily monitoring by visual

expecting provides any instability at pit

operational. eventhought it can not be used

as mine point to rate instability on open pit

mining but daily inspection monitoring at

field could be a cross and check data and

assist site monitoring slope stability program

such as prism deformation data, crack

extensometer and advanced instrument as

slope stability radar monitoring.

This geotech daily monitoring report

inspection by visual and done regularly

every day on pit active area that becoming

pre-elemenary report before mine

operational continioud.

Monitoring program by visual expected to

help site employees on level supervisor and

foreman to understand risk and potention of

slope instability on site and to understanding

all employees level (higher position till

managemen) which is expected facilitate the

determination of slope stability risk.

Objective

Daily inspection monitoring program as a

regular daily report by visual as one of slope

stability monitoring program expecting can

ensure of safety operational needs as follow:

a. As a reference for slope stability risk

assessment on field supervisor and

foreman level.

b. Pre-eleminary report by geotech

person on a slope stability risk

assessment report.

c. As a comparative data with data

deformation existing such as prism

deformation and radar deformation.

d. Assessment by visual is objective

which daily inspection report should

be done by experienced employees

with standart operational procedure

on mine pit operational.

e. Result of daily monitoring risk

assessment report would be guide to

the next step for prevention and

coordination line.

f. Carried on daily regularly.

GUIDELINES OF DAILY GEOTECHNICAL INSPECTION PIT AS A

ONE OF DAILY MONITORING SITE PROGRAM

Geotechnical Inspection Program

Stage of investigation

1. Item Description

Checklist description consist of 18 item on

daily inspection report by visual. Certainly

every mine site issue are different and

depends on risk assessment that could be

change as needed. 18 checklist item can be

combined with other issue such as

environmental, economics etc and resulting

collective mine site risk assessment.

4 primary framework on checklist inspection

consist of : suitability with mineplan design,

geological structure, water influence,

standart operational procedure and residual

risk potention.

a. Suitability with mineplan design

Design issued certainly has passed

geotechnical assessment and

research of slope stability and

accepted by government related

which is used primary data from

geotechnical drilling. Operational at

field must be according with the

design issued (final design and

temporary desing) for slope stability

from top crest of pit to the buttom of

pit. Review suitability with mineplan

design could control production from

over/under cut potention. On the

checklist inspection description case

including suitability design with

actual of toe, crest, bench and slope

face. Conclusions from suitability

design with actual resulting question

: is it crest/ toe/ bench actual

according with mineplan design ?

Foto 1A. Longsor bench akibat Ketidak

seusaian design dan actual lapangan

Foto 1B. Overcut toe pada design final

menimbukan ketidakstabilan.

b. Geological Structure

Geological structure on slope

stability much influences case. In

addition to the cross section

geological modeling by software,

field measurements pit active are

required because other some case

found minor geological structure that

influence slope instability.

Geotechnical Inspection Program

Comparing and rechecking actual

condition with geological model as

neccecary needs especially on dip of

slope, crack existing, fault, fold and

normal/reverse fault that coulnd be

“weak layer” on sediments layer and

decreasing of slope stability.

Geological structure case resulting

checklist questions Is It geological

structure influence slope stability ?

and describe all geological

structure found.

Foto 2A. geological structure field

measurements that have potention for slope

instability.

Foto 2b. failure potention map by measuring

minor field geological structure .

Foto 2b. Map potention and minor

geological structure field measurement

c. Water Influences

Water surface and underground at

mine pit significantly influencing on

slope stability. Water at mine pit

active could increase slope instability

including as a media on “weak layer”

sediment could triggering slope

failure and saturating sediment that

increasing load of sediments

material, water flowing at toe can be

eroded toe of slope that steppening

of slope face. On water influence the

questions is Is water spring,

dewatering surface water and

water ponding at crest of pit that

affect slope stability ?

Foto 3A.water ponding at pit crest(unsafe

condition).

A

Geotechnical Inspection Program

Foto 3B. perimeter drainage for surface

water around pit avoid water coming to the

pit edge.

d. Standart Operational Procedure.

Standart operational procedure

related with slope stability compiled

by research by person in charge.

Technically standart operational

procedure contained of paper

registered on company procedure

document. Procedure in associated

with slope stability consist of

digging at slope with 5 meter

maximum high at muddy material,

survey pig as a reference for crest,

toe, slope establishment, blasting

pattern on geological strucuture

affected area, waste dump crest

distance and other procedure related.

Foto 4A. unprosedural digging on muddy

material (morethan 10 m high).

Foto 4B. Operational prosedur muddy

material with not more than 5 meter high.

e. Residueal Risk.

Residual risk are slope instability

which is accapteble and not directly

affect on mine operational pit.

Residual risk in term is employees

and equipment safe from instability

risk like creeping muddy material,

rockfall potention, access ramp, and

risk associated with community. The

questions on checklist description are

Is it equipment distance with failure

potention are good, is it access ramp

good, is it other failure potention

associated with community good.

Foto 5. Rockfall potention as an example of

residual risk (no activity below risk

potention).

Geotechnical Inspection Program

Daily inspection monitoring checklist has 3

term from condition description consist of

“good” 1 point, “no good” 5 point, and

“bad” 25 point.

Tabel 1. Table checklist item with value term

from condition description

No Condition decription value 1 Good 1 2 No Good 5 3 Bad 25

N

o Item condi

tion value

1 is it Crest well/suitable

with design ? √ 1 / 5 / 25

2 is it toe well/suitable with

design ? √ 1 / 5 / 25

3 is it Bench/berm well

suitable with design √ 1 / 5 / 25

4 is it Structural Geology

effect ? √ 1 / 5 / 25

5 is it Crack/buldging

existing ? √ 1 / 5 / 25

6 Is it Hanging Block

(Description) ? √ 1 / 5 / 25

7 is it Diverting Channel

good ? √ 1 / 5 / 25

8 is it drainage around Pit

good ? √ 1 / 5 / 25

9 Is it drainage at wall final

? √ 1 / 5 / 25

10 Is it Water Pond ? √ 1 / 5 / 25

11 Is it Spring existing ? √ 1 / 5 / 25

12 Wall final pig (sign) ? √ 1 / 5 / 25 13 Digging with max 5 m

high (muddy/sandy) ? √ 1 / 5 / 25

14 Digging with max 10 m

height ? √ 1 / 5 / 25

15 is it Blasting affect ? √ 1 / 5 / 25 16 distance equipment with

failure potention ? √ 1 / 5 / 25

17 is it waste dump at crest

(50 m distance) ? √ 1 / 5 / 25

18 Access ramp (wide,grade,

failure potention) ? √ 1 / 5 / 25

Nilai Total ?

2. Term Risk With Control.

After field inspection and measurements 18

checklist then total value calculating and

resulting total value based on risk existing.

Risk existing associated with control that

should to do consist of 5 term control :

- Low Term Risk is lower risk/ acceptable

risk (level 1). Value of Checklist based

on field inspection and measurements

resulting from 0 to 30 point. Control :

Accept risk and manage by routine

procedure. No blasting warn

- Low – Medium Term Risk is risk level 2.

Value of Checklist based on field

inspection and measurements resulting

from 31 to 56 point. Control : routine

procedure, coordination with other

section/person in charge, coordination

with blasting section if geotechnical term

in “bad” point.

- Medium Term Risk is risk level 3. Value

of checklist based on field inspection and

measurements resulting 57-160 point.

Control : section in charge responsibility

assigned, corrective and preventive

action, blasting hole limit 20 meter from

freeface. Re-assessment needs for

blasting at critical area.

- Medium – high term risk is risk level 4.

Value of checklist based on field

Geotechnical Inspection Program

inspection and measurements resulting

141 - 250 point. Control : management

attention, immediate corrective and

preventive action required. No blasting

activity. Research and re-assessment

needs for blasting at critical area.

- High term risk is risk level 5. Value of

checklist based on field inspection and

measurements resulting 250 – 450 point.

Control : cease activity or task, detailed

research and planning required. no

blasting activity. Research and re-

assessment needs for blasting at critical

area.

Table 3. Table term risk with control by total

value 18 checklist field isnpection.

Risk Value Control

Low 0-30 Accept risk, Manage

by Routine procedure.

Low-

Medium 31-56

Routine procedure,

coordination with

other section/person

incharge.

Medium 56-140

Section in charge

responsibility

assigned, Corrective

and preventive action

plan

Medium-

High

141-

250

Management

Attention, immidiate

corrective and

preventive action

required.

High 251-

450

Cease activity or task,

detailed research and

planning required.

3. Action Implemented

Action implemented is next step as a

corrective and preventive action to

decreasing risk level. Action implemented

could be direcly done after inspection,

advance research and analyze that resulting

action to decreasing risk level. Action

implemented may decrease term risk level

with 1 or 2 level. Action implemented

consist of 5 action :

a. Slope modification

Slope modification mean lowering slope

face or cut out material which have

failure potention. Other option slope

modification is construct bundwall at toe

of slope with failure potention.

Foto 6.A. Bundwall contruction schema as

bermweight on muddy material

b. Drainage control works

Drainage control works mean controlling

for water spring/groundwater and surface

water that affect slope stability by

infiltrating on slope/structural geology

Geotechnical Inspection Program

layers. Dranaige control can be use

drainhole method with water level

monitoring (pziometer) for draining

undergroundwater. Drainage control for

surwace water usually with perimeter

drainage around pit edge.

Foto 6.B. water infiltrated schema from surface

water to lowwall pit.

c. HSE implementation

HSE implementation with identification

instability existing as warn information

sign for employees and as a preventive

action before andvance research and

analysis. HSE implementation example

safety barricade, geotech warning sign

and other warning sign.

Foto 6.B. safety barricade installation as a

warning sign for instability area.

d. Geotechnical Investigation and Analysis

Geotechnical investigation and analysis is

advance detailed research and analysis

with software and other instrument as a

corrective action. Software analyze

including slide, phase2, detailed research

on fieLd by spt test, cone penetrometer

test, geological structure measurement

etc. Report detailed research and

investigation used as a recommendation

for mineplan and operational section.

Foto 7.A. factor of safety analysis used software

slide v 5.0. sample geotechnical anilysis after

detaild research actual condition and resulting

geotechnical recommendation.

Geotechnical Inspection Program

e. Geotechnical instrument monitoring

Installing geotechnical and monitoring

regularly (daily or weekly) by person in

charge (geotech/pit geologist) is

geotechnical instrument monitoring. Data

monitoring used as information for

advance research and detailed and as a

preventive any instability issue at pit.

Instrument used in this program including

prism monitoring, water level monitoring

(undergroundwater) slide monitoring

alarm, crack extensometer and advance

instrument monitoring such as slope

stability radar by GroundProbe.

Foto 8A. slide monitoring alarm and crack

extensometer as a geotechnical instrument

monitoring

Tabel 4. table action implemented

No Action impelented Yes/

No Nilai

1 Cutting back to flatten

slope batter Y/N 15/0

2

Construction of

intermediate berms or

removel of loose

material/waste/side fills

Y/N 15/0

3 seepage control works Y/N 15/0

4 surface water run off

control Y/N 10/0

5 Hazard Identification Y/N 5/0

6 Instalation of warning

signage and safety

barricades Y/N 5/0

7 Investigation programmes

and analyses and remedial

design Y/N 15/0

8 Instalation of geotechnical

monitoring instruments Y/N 10/0

9 Reguler site inspection by

on site geologist Y/N 10/0

10 TOTAL RATING ?

Tabel 5. Rating menurunkan tingkat resiko

No Total Rating Risk Decrease

1 0 - 40 0

2 >40 - 60 1

3 > 60 2

Geotechnical Inspection Program

Description 18 item on

checklist

Risk Assesment 1. Low

2. Low - Medium

3. Medium

4. Medium – high

5. High

1. Accept risk, Manage by Routine procedure.

2. Routine procedure, coordination with other

section/person incharge.

3. Section in charge responsibility assigned,

Corrective and preventive action plan.

4. Management Attention, immidiate

corrective and preventive action required.

5. Cease activity or task, detailed research and

planning required.

Control term Risk

- Cutting back to flatten slope batter.

- Construction of intermediate berms or

removel of loose material/waste/side fills

- seepage control works

- surface water run off control

- Hazard Identification

- Instalation of warning signage and safety

barricades

- Investigation programmes and analyses

and remedial design

- Instalation of geotechnical monitoring

instruments

- Reguler site inspection by on site geologist

Action Implemented

Evaluation, Conclusions and

Recommendation report

Flowchart on guidelines daily Geotechnical Inspection Pit Monitoring

Total 18 checklist number (0 – 450 )