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Contract No. CM 04/2024 – Outlying Islands Sewerage Stage 2 – South
Lantau Sewerage Works – Environmental Team Services (2025 - 2027) |
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Quarterly Environmental Monitoring, and
Audit Report for: May to July 2025 Revision
5 |
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______________ Ting
Po Chung, Ivan Environmental
Team Leader Report
Date: 30
September 2025 |
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Content:
1.2 Environmental
Monitoring & Audit Programme
1.3 Quarterly
Environmental Monitoring & Audit Report
2. Basic project
Information and Environmental Status
2.3 Works
undertaken during the Reporting quarter
3. Environmental
Monitoring and Audit (“EM&A”) Requirement
3.1 Summary of Monitoring Parameters
3.2 Environmental quality performance
limits (Action and Limit levels); and Results Summary
3.3 Implementation Status of
Environmental Mitigation Measures
3.4 Complaints, Non-Compliance, and
Notification of Summons and Prosecution
4.1 Environmental
Monitoring and Audits
4.2 Implementation
of Environmental Mitigation Measures
Tables:
Table 2.1: Contact Details of Key Personnel
Table 3.1: Summary of Impact EM&A Requirements
Table 3.2: Action and Limit Levels for Noise Monitoring
Table 3.3: Action and Limit Levels for Water Quality
Table 3.4: Summary of Ecological Impact Monitoring
Table 3.5: Summary of
Quantities of Waste Material in the Reporting Quarter
Figures:
Figure
3.1 Locations of Noise Monitoring
Station
Figure
3.2 Locations of Water Quality
Monitoring Station
Appendices:
Appendix
3.1 Noise Monitoring Graphical
Presentations
Appendix
3.2 Marine Water Quality Monitoring
Graphical and Summary of Exceedance Presentations
Appendix
3.3 Waste Material in the Reporting
Quarter
This Quarterly
Environmental Monitoring and Audit (“EM&A”) Report summarises project monitoring, and auditing data, with full
interpretation illustrating the acceptability or otherwise of any environmental
impacts, and identification or assessment of the implementation status of
agreed mitigation measures, including monitoring results, and findings of the
EM&A Programme, along with findings recorded during the site Inspections,
and audits, reports of Complaints, Notifications of Summons, and Successful
Prosecutions, and other necessary observations obtained within this reporting
quarter from 1 May 2025 to 31 July 2025.
Key Construction
Works in the Reporting quarter
San Shek Wan Sewage Treatment
Works (“SSWSTW”)
·
Excavation and site formation
·
Superstructure RC works
·
Retaining wall construction
Dredging and diffuser
construction
·
Waterproofing work
Pui O Sewage Pumping
Station (“POSPS”)
·
Excavation and ELS work
E&M Installation
Lo Uk Tsuen, Pui O
·
Excavation, sewer laying, construction of
manhole
South Lantau Road
·
Excavation, sewer laying, construction of
manhole
Chi Ma Wan Road
·
Excavation, sewer laying, construction of
manhole
Trenchless drilling works
Environmental Monitoring,
and Audit Progress
The EM&A
Programme is implemented in accordance with the EM&A Manual under the EIA
Report. A summary of the monitoring activities during this reporting quarter as
below:
|
Monitoring Activity |
Monitoring Date |
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|
May 2025 |
June 2025 |
July 2025 |
|
|
Noise |
10, 16, 22 and 28 |
3, 9, 20, 26 and 30 |
11, 18-19, 24 and 30 |
|
Water Quality |
3, 6, 8, 10, 13, 15, 17,
20, 22, 24, 27 and 29 |
N/A |
N/A |
|
Nursery visit for
transplanted trees |
27 |
30 |
28 |
|
Site Inspection |
7, 12, 19 and 27 |
2, 9, 16, 23 and 30 |
7, 14, 21 and 28 |
Breaches of Action,
and Limit Levels
A summary of
environmental exceedances for this reporting quarter is as follows:
|
Environmental
Monitoring |
Parameters |
Action Level |
Limit Level |
|
Noise |
Leq
(30 min) |
0 |
0 |
|
Water
Quality |
Suspended
solids level (“SS”) |
0 |
0 |
|
Turbidity
level |
0 |
0 |
|
|
Dissolved
oxygen level (“DO”) |
24 |
0 |
Ecological Impact
Monitoring
Transplanting of the
trees of Aquilaris sinensis was completed
on 26 April 2022. Maintenance works for trees in holding nursery have
commenced.
4 trees found (1 no.
of Aquilaria sinensis, and 3 nos. of Gmelina chinensis) within
the site of SSWSTW which are considered to be the
plant species with conservative importance for temporarily transplanted to the
nursery at Kam Tin, and eventually be transplanted to
POSPS.
The weekly site
audit was carried out by ET include checking whether good site practices are
being properly implemented by the Contractor.
The extent of the
work site boundaries was checked by the ET during the weekly site audit.
Complaints,
Notification of Summons and Prosecution
No environmental
complaint was recorded in the reporting quarter.
No notification of
summons and successful prosecution regarding construction works were recorded
in the reporting quarter.
Reporting Changes
There are no reporting changes in the
reporting quarter.
1.1.1
The Environmental Protection Department (“EPD”) completed
the Outlying Islands Sewerage Master Plan (“SMP”) Study in 1994 and drew up a
SMP for Lantau Island and other outlying islands. The proposed sewerage works
of the SMP were divided into 2 stages. The Stage 2 Works of the SMP were
subsequently reviewed by EPD under the Outlying Islands Sewerage Master Plan
Stage 2 Review (SMP Review Study) in 2001.
1.1.2
The proposed sewerage works for South Lantau
were further reviewed in 2008 under the Review of Sewerage Scheme for South Lantau
(Review Study). According to the Review Study, the proposed sewerage works for
South Lantau would serve the unsewered areas of Shui Hau, Tong Fuk, Cheung Sha,
San Shek Wan, Pui O and Ham Tin.
1.1.3
The Outlying Islands Sewerage Stage 2 – South
Lantau Sewerage Works, herein referred to as “the Project”, referred to the
sewerage works for South Lantau that would serve the unsewered areas of Shui
Hau, Tong Fuk, Cheung Sha, San Shek Wan, Pui O and Ham Tin.
1.1.4
The Project mainly comprises of the following
items:
a)
Construction of a secondary sewage treatment
works (“STW”) at San Shek Wan in South Lantau;
b)
Construction of sewage pumping station (“SPS”)
at Pui O, San Shek Wan, Cheung Sha, Cheung Fu Street, Shui Hau and Tong Fuk;
c)
Construction of about 1.4km of twin submarine
outfalls with a diameter of 350mm for the disposal of treated effluent from the
STW at San Shek Wan;
d)
Construction of about 10.1km of gravity sewers
with diameters ranging from 150mm to 375mm along South Lantau Road and Chi Ma Wan
Road and at Pui O; and
e)
Construction of about 3.1km of twin rising mains
with a diameter of 200mm to 250mm along South Lantau Road and Chi Ma Wan Road.
1.2.1
An Environmental Impact Assessment (“EIA”) was
subsequently prepared to review the potential environmental impact that would
be due to the Project during its construction works and operational works. The
EIA Report was submitted and approved on 24 April 2017, and Environmental Permit
(“EP”) No. EP-538/2017 was subsequently granted on 13 July 2017.
1.2.2
The EM&A Programme is therefore implemented
in accordance with the EM&A Manual under the EIA Report.
1.2.3
Umwelt Consulting Limited (“UCL”) has been
appointed to work as the Environmental Team (“ET”) under EP No. EP-538/2017 to
implement the EM&A programme as stipulated in the EM&A Manual of the
approved EIA Report for the Outlying Islands Sewerage Stage 2 – South Lantau
Sewerage Works (Register No.: AEIAR-210/2017).
1.3.1
This Quarterly EM&A Report summarises project monitoring
and auditing data, with full interpretation illustrating the acceptability or
otherwise of any environmental impacts and identification or assessment of the
implementation status of agreed mitigation measures, including monitoring results
and findings of the EM&A Programme, along with findings recorded during the
site Inspections and audits, reports of Complaints, Notifications of Summons and
Successful Prosecutions, and other necessary observations obtained within this
reporting quarter form May 2025 to July 2025.
2.1.1
Drainage Services
Department (“DSD”) is the project proponent and the permit holder of the
Project. For the construction phase of the Project, Contractor(s), ET and
Independent Environmental Checker (“IEC”) are appointed to manage and control environmental
issues. Key personnel and contact particulars are summarized in Table 2.1.
2.1.2
Upon conclusion of
Contract No: SD 15/2022 Outlying Island Sewerage Stage 2 – South Lantau Sewage
Works – Environmental Team Services (2023 – 2024), the subsequent contract,
Contract No. CM 04/2024 Outlying Islands Sewerage Stage 2 – South Lantau
Sewerage Works – Environmental Team Services (2025-2027), has been awarded to
Umwelt Consulting Limited (“UCL”) starting 1 February 2025. As such the environmental
team leader (“ETL”) appointed for the Project has been updated to Mr. Ting Po
Chung, Ivan since 1 February 2025. His contact details has been updated in Table 2.1.
2.1.3
There are no other
reporting changes in the reporting quarter.
Table 2.1: Contact
Details of Key Personnel
|
Party |
Role |
Post |
Name |
Contact No. |
Contact Fax |
|
Drainage Services Department |
The Engineer for the Contract |
Engineer |
Mr. KK Chan |
2594 7297 |
3104 6426 |
|
Binnies Hong Kong Limited |
Engineer’s Representative |
Resident Engineer |
Mr. Kevin Chan |
3529 3003 |
- |
|
Kwan Lee – Chun Wo
Joint Venture |
Contractor |
Sub Agent |
Mr. Daniel Chu |
6737 6701 |
2744 6937 |
|
Environmental Supervisor |
Ms. Joey Pang |
6978 2876 |
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Environmental Supervisor |
Mr. Philip Wong |
6908 8920 |
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SMEC Hong Kong |
IEC |
IEC |
Ms. Kitty Lee |
3995 8140 |
3422 3631 |
|
Umwelt Consulting Limited |
ET |
ET Leader |
Mr. Ivan Ting |
3756 9590 |
3582 3310 |
2.2.1
The proposed sewerage
works will collect the sewage generated from the unsewered areas of Shui Hau,
Tong Fuk, Cheung Sha, San Shek Wan, Pui O and Ham Tin in South Lantau (i.e.
within the Project Catchment Area) and convey it to a proposed sewage treatment
works at San Shek Wan for treatment and disposal into outer bay of Pui O / Chi
Ma Wan via a submarine outfall.
2.2.2
The Project was divided into 3 contracts. The current contract, Contract No. DC/2020/02
- Construction of San Shek Wan Sewage Treatment Works, Associated Submarine
Outfall and Pui O Sewerage Works (“the Contract”) would have the following implementations. The works site of the Contract
is also given in Figure 2.1.
2.2.3
The major components
of the Contract under Environmental Permit (“EP”) (EP No. EP-538/2017)
comprises:
a) Construction of a secondary sewage treatment works
(“STW”) at San Shek Wan in South Lantau;
b) Construction of a sewage pumping station (“SPS”) at
Pui O, San Shek Wan, Cheung Sha and Cheung Fu Street;
c) Construction of about 1.4km of submarine outfall
with a diameter of 350mm for the disposal of treated effluent from the STW at
San Shek Wan;
d) Construction of about 10.1km of gravity sewers with
diameters ranging from 150mm to 375mm along South Lantau Road and Chi Ma Wan road and at Pui O; and
e) Construction of about 3.1km twin rising mains with
a diameter of 200mm to 250mm along South Lantau Road and Chi Ma Wan Road.
2.3.1
In the reporting quarter, the principal work
activities conducted are as follow:
a)
Excavation and site formation
b)
Superstructure RC works
c)
Retaining wall construction
d)
Dredging and diffuser construction
e)
Waterproofing work
a)
Excavation and ELS work
b) E&M Installation
a)
Excavation, Sewer Laying, and Construction of Manhole
a)
Excavation, Sewer Laying, and Construction of Manhole
a)
Excavation, Sewer Laying, and Construction of Manhole
b)
Trenchless drilling works
3.1.1
The EM&A programme requires environmental monitoring, noise
monitoring, water quality monitoring, and ecology as specified in the approved
EM&A Manual.
3.1.2
A summary of Impact EM&A requirements is presented in Table 3.1. The locations
of noise monitoring stations, and water quality monitoring
stations are shown in Figure 3.1 and Figure 3.2 respectively.
Table 3.1: Summary of Impact EM&A Requirements
|
Environmental
Monitoring Aspects |
Parameters and
Unit |
Monitoring Station |
Frequencies |
Remarks |
|
Noise |
Leq (30mins), L10 (30mins)
and L90 (30mins) |
N12a, N12b,
N13, N14, N15b, N16a, N16b, and N17 |
At least once per
week |
Daytime on normal
weekdays (0700-1900 hrs). |
|
Water Quality |
Dissolved Oxygen,
mg/L Temperature, °C Salinity, 0/00 Turbidity, NTU Suspended Solids,
mg/L pH |
CE, CF, SR4,
SR5, SR6, SR9, SR10, SR12, and SR15 |
Three times per
week during mid-ebb, and mid-flood tides |
Samples are
collected at 3 depths (1 m below water, mid-depth, and 1 m above seabed)
shall be collected. Where the water
depth is less than 6 m, in which case the mid-depth station may be omitted. Should the water
depth be less than 3 m, only the mid-depth station will be monitored |
3.2.1
A-weighted equivalent continuous sound pressure level (“Leq”) over a period of 30 minutes Leq (30min) shall
be used as the monitoring parameter for construction noise monitoring.
Supplementary information for data auditing, statistical results such as L10,
and L90 should also be recorded for reference.
3.2.2
For impact monitoring of construction works, noise monitoring should be undertaken
on weekly basis. Six consecutive Leq
(5min) between 07:00-19:00 hours on normal weekdays is taken in this
EM&A Programme.
3.2.3
During the reporting period, school examinations were held from 15 to16
May, 4 to 6, 9 and 16 to 17 June 2025. Accordingly, the noise limit for
monitoring station N17-Bui O Public School was temporarily reduced to 65 dB(A)
on these examination. The standard noise limit of 70
dB(A) remained applicable for all other days outside this examination
period.
3.2.4
The Action and Limit Levels for noise monitoring are given as in Table 3.2.
Table 3.2: Action and Limit Levels for Noise Monitoring
|
Monitoring
Station ID |
Monitoring
Location |
Action Level |
Limit Level |
|
N12a |
Lo Uk Tsuen |
When one documented complaint is received from
any one of the noise sensitive receivers |
75 dB(A) |
|
N12b |
Lo Uk Tsuen |
75 dB(A) |
|
|
N13 |
Pui O San Wai
Tsuen |
75 dB(A) |
|
|
N14 |
South Lantau
Community Centre |
75 dB(A) |
|
|
N15b |
Pui O Lo Wai Tsuen |
75 dB(A) |
|
|
N16a |
Residences at Ham
Tin |
75 dB(A) |
|
|
N16b |
Residences at Ham
Tin |
75 dB(A) |
|
|
N17 |
Bui O Public
School |
70 dB(A) / 65
dB(A) 1 |
Note:
1. The Limit Level for N17 is 70 dB(A) for
being an educational institution. The Limit Level is reduced to 65 dB(A) during
school examination period.
3.2.5
No exceedance was recorded for the reporting quarter. The detailed
results and graphical plot for noise monitoring is given in Appendix 3.1.
3.2.6
In construction phase, the levels of dissolved oxygen (“DO”),
temperature, turbidity, and salinity should be measured in-situ while suspended
solids (“SS”) is determined by laboratory analysis.
3.2.7
The Action and Limit Levels for water quality monitoring are given as in
Table 3.3.
Table 3.3: Action and Limit Levels for Water Quality
|
Parameters |
Action Level |
Limit Level |
|
DO in mg/L 1 |
Surface, and Middle Level: |
Surface, and Middle Level: |
|
Turbidity in NTU
(Depth-averaged 2) 3 |
14.4 NTU and |
23.5 NTU and |
|
SS in mg/L (Depth-averaged 2)
3 |
13.1 mg/L and |
30.4 mg/L and |
Notes (with proposed amendments in AL/LL in
underlined text):
1. For DO, non-compliance of the water quality
limits occurs when monitoring result is lower than the limits.
2. “Depth-averaged” is calculated by taking the
arithmetic means of reading of all 3 depths
3. For SS, and turbidity, non-compliance of the
water quality limits occurs when monitoring result is higher than the limits.
4. Action Level, and Limit Level with 95%-ile / 99%-ile derived from
baseline data “and” 20% / 30% exceedance of control station proposed in
Baseline Monitoring Report.
3.2.8
The marine construction works were completed in May 2025, with the silt
curtain removed on 24 May 2025 in accordance with the approved Silt Curtain
Deployment Plan.
3.2.9
Action level exceedances were recorded for dissolved oxygen on 17 to 29 May
2025. Investigations have been conducted
accordingly and concluded the exceedances were not project related. The
detailed results and graphical plot for water quality monitoring is given in Appendix
3.2.
3.2.10 From 17 to 22 May 2025, no
marine works were carried out, and the sampling team did not observe any
abnormalities during water quality monitoring, so this DO exceedance is
determined to be caused by natural fluctuations and unrelated to the project.
3.2.11 On 24 May 2025, marine works
including removal of the silt curtain and cutting of the casing were conducted;
however, such works would not introduce pollutants affecting DO, and the
sampling team found no abnormalities in water quality monitoring, thus this DO
exceedance is also judged to result from natural fluctuations and have no
connection with the project.
3.2.12 No marine works were
performed on 27 and 29 May 2025, and the sampling team did not detect any abnormalities
during water quality monitoring, leading to the conclusion that this DO
exceedance is attributed to natural fluctuations and not related to the
project.
3.2.13 A site investigation was
conducted on 30 May 2025, during which seawater abnormalities were found,
suspected to be an algae bloom. In summary, this DO exceedance is also
determined to be caused by natural fluctuations and unrelated to the project.
3.2.14 Subsequent
to the completion of marine work on 24 May 2025,
water quality monitoring
was
considered completed by 30 May 2025. No water quality monitoring is conducted
in June and July 2025.
3.2.15 Should marine works
resume, water quality monitoring will be conducted in accordance
with
the requirement stipulated in the EM&A Manual accordingly.
3.2.16 Monitoring in the form of
regular site inspections should be carried out to ensure ecological measures in
the form of tree transplantation, and establishment are being implemented, and
effective for plant species of conservation importance (e.g. Aquilaria
sinensis).
3.2.17 Transplanting works for
plant species, Aquilaris sinensis, was
completed on 26 April 2022. Maintenance works for trees in holding nursery have
commenced.
3.2.18 Monitoring of maintenance
works for the transplanted plant species was conducted at the holding nursery
while in the reporting period.
3.2.19 As per latest version of
PTP, four tree found (1 no. of Aquilaria sinensis,
and 3 nos. of Gmelina chinensis) within the site of SSWSTW which are considered to be the plant species with conservative
importance for temporarily transplanted to the nursery at Kam Tin and
eventually be transplanted to POSPS.
3.2.20
Within this reporting
period, holding nursery visit for transplanted trees on 24 February, 24 March
and 23 April 2025.
3.2.21
No non-compliance was
found during the site inspection while reminders on environmental measures were
recommended. Results and findings of these inspections in this reporting period
are listed below in Table 3.4.
Table 3.4: Summary of Ecological Impact Monitoring
|
Inspection
Date |
Reminder
and Recommendations |
Close-out
Date / Status |
|
27
May 2025 |
The
contractor is reminded to clear
the weeds. |
-- |
|
30
June 2025 |
The
contractor is reminded to properly
install the tree tag. |
Contractor
has rectified the reminders
on 15 July 2025 |
|
28
July 2025 |
The
contractor is reminded to replace
faded tree tag. |
Contractor
has rectified the reminders
on 13 August 2025 |
3.2.22
The quantities of waste for disposal in
present quarter are summarized in Table 3.5.
Table 3.5: Summary of
Quantities of Waste Material in the Reporting Quarter
|
Waste Type |
Quantity for Reporting Quarter |
Cumulative Quantity-to-Day |
|
Hard Rock and Large Broken Concrete (Inert), in ‘000m3 |
0 |
0 |
|
Reused in this Contract (Inert),in ‘000m3 |
0 |
0 |
|
Reused in other Projects
(Inert), in ‘000m3 |
0 |
0 |
|
Disposal as Public Fill
(Inert), in ‘000m3 |
0.43 |
29.91789 |
|
Metals (in ‘000kg) |
67.2553 |
83.03907 |
|
Paper / Cardboard Packing, in
‘000kg |
0.1693 |
1.19988 |
|
Plastics in ‘000kg |
0.0049 |
0.10506 |
|
Chemical Waste in ‘000kg |
0 |
0 |
|
General Refuse in ‘000kg |
98.07 |
897.32 |
Note:
The table is summary
of quantities of waste material of May to July period.
3.3.1
The mitigation measures recommended in the EIA
Report has been implemented where applicable. The implemented mitigation
measures for the reporting quarter are listed below:
a)
Implementation of noise mitigation measures
in accordance with Construction Noise Mitigation Plan, including the use of
quality powered mechanical equipment, use of noise barriers, and locating noisy
equipment away from noise sensitive receivers as far as possible;
b)
Dust control during dust generating works, including
watering of construction works site, covering the stockpile stored on site,
provision of wheel-washing facilities for vehicles at the site entrance;
c)
Water quality mitigation measures including
the setting up of silt curtain at the marine works site, and maintained in good
condition during the marine works;
d)
Adopt surface drainage and sediment control
facilities for sewage installation in village and public roads;
e)
Adopt temporary drainage and sediment control
facilities on Site; and
f)
Proper waste handling, recycling and storage.
3.3.2
The implemented mitigation measures are
considered effective.
3.4.1
No environmental complaint was recorded in the
reporting quarter.
3.4.2
No environmental non-compliance was recorded in
the reporting quarter.
3.4.3
No notification of summons and successful prosecution
regarding construction works were recorded in the reporting quarter.
4.1.1
Environmental
monitoring and audits including Noise, Water Quality, Ecology, and Site audits
have been conducted in the reporting quarter in accordance with the requirement
stipulated in the EM&A Manua.
Noise Monitoring
4.1.2
Noise Monitoring has
been conducted at 8 of the designated monitoring locations where construction works
has been conducted nearby during the reporting period.
4.1.3
During the reporting
period, school examinations were held from 15 to 16 May 2025. Accordingly, the
noise limit for monitoring station N17-Bui O Public School was temporarily reduced
to 65 dB(A) on these examination days (15-16 May 2025). The standard noise limit of 70 dB(A) remained applicable for all other days
outside this
examination period.
4.1.4
No action or limit
level exceedance was recorded in construction noise level in this reporting period.
Water Quality Monitoring
4.1.5
Marine Water Monitoring has been conducted at 9 designated monitoring
locations during the reporting period.
4.1.6
Action level exceedance was record for dissolved oxygen on 17 to 29 May
2025. Investigations were conducted and site investigation was conducted on 30
May 2025.
4.1.7
Marine works were completed on 24 May 2025. The silt curtain was removed
and cutting of casing on the same day in accordance with the site curation
deployment plan. No other marine works were conducted in May 2025.
4.1.8
As the exceedances would be due to natural fluctuation, and the marine
works have been completed. Hence, the water quality monitoring was not extended
in spite of the exceedance recorded on 29 May 2025.
4.1.9
Subsequent to the completion of marine work on 24 May
2025, water quality monitoring was
considered completed by 30 May 2025, unless marine works would be resumed.
Ecological Impact Monitoring
4.1.10 Transplanting of the
trees of Aquilaris sinensis was completed
on 26 April 2022. Maintenance works for trees in holding nursery have
commenced.
4.1.11 As per latest version
of PTP, 4 tree found (1 no. of Aquilaria sinensis and
3 nos. of Gmelina chinensis) within the site of SSWSTW which are
considered to be the plant species with conservative importance for temporarily
transplanted to the nursery at Kam Tin and eventually be transplanted to Pui O
Pumping Station.
4.1.12 The weekly site audit
was carried out by ET include checking whether good site practices are being properly
implemented by the Contractor.
4.1.13 The extent of the
work site boundaries was checked by the ET during the weekly site audit.
4.1.14 No
non-compliance was found during the site inspection while reminders on
environmental measures were recommended.
4.2.1
The mitigation measures recommended in the EIA Report has been
implemented where applicable. The implemented mitigation measures are
considered effective.