MINE DESIGN AND PLANNING

Transcription

1 TE KUHA PROJECT STEVENSON MINING LIMITED AUGUST 2016 V13 MINE DESIGN AND PLANNING

2 MINE DESIGN

3 PIT DESIGN DESIGN Pit Slope Design is based on 10m high horizontal benches to allow for steep dipping coal to be uncovered and removed along each bench Final Pit wall (Blue line) - has bench design angles of 63 degrees with a 15m offset on every third bench Only the final wall has this profile, strips are mined in advance so that overall wall angle is shallower Average Final Pit wall overall design angle is 50 degrees and Active Mining Strip wall overall design angle is 38 degrees Further detailed geotechnical testing and evaluation are required for the ELF and pit design to ensure stability

4 PIT DESIGN PLAN VIEW DESIGN Strip 5 North Ridge Line design is based on 5 x 140m wide strips design is based on 8 x 100 m wide strips In areas where the overlaps the lower, the is mined before the extends into the area

5 PIT DESIGN PLAN VIEW DESIGN Small Upper ELF Foot Print LEGEND - Total Footprint Main Lower ELF Foot Print Upper Topsoil ELF Foot Print - Access Road - Pit Shell Original Ephemeral pond New Ephemeral pond Brunner Pit Shell Year 1 clean water drain - Clean water drain - Dirty water drain - ELF Footprint Lower Topsoil ELF and access road Foot Print Paparoa Pit Shell Mine footprint Year 1 dirty water drain North

6 PIT DESIGN PLAN VIEW with 5m CONTOURS LEGEND - Green 5m contours - Purple 25m contours DESIGN Original Ephemeral pond Zone Small Upper ELF Foot Print Upper Topsoil ELF Foot Print - Pit Shells - Total Footprint - Access Road New Ephemeral pond - Dirty water drain - Clean water drain Main Lower ELF Foot Print Brunner Pit Shell - ELF Outline Year 1 clean water drain Paparoa Pit Shell Total footprint Lower Topsoil ELF and access road Foot Print North Year 1 dirty water drain

7 PIT DESIGN ORTHO PLAN WITH AREAS LEGEND - Green 5m contours - Purple 25m contours DESIGN - Total Footprint Potential ELF 6.5 Ha Topsoil 1.8 Ha Topsoil 9.6 Ha - Access Road - Paparoa & (Overlapping) - (Not Overlapping) ELF 20.7 Ha ELF 4.5 Ha - (Not Overlapping) - Topsoil ELF - Ex-pit ELF - Permanent Sumps - Other Disturbed Topsoil 4.9 Ha

8 PIT DESIGN LOOKING SOUTH EAST DESIGN North

9 Total 15,205,614 3,553, Year is material removal only to rehabilitate the minesite No minimum thickness / loss or dilution have been applied Not compliant to JORC or Valmin code SCHEDULE BY YEAR - COMBINED OUTPUT BOTH PITS Year Emplacement Material Volume ROM Coal Mined Strip Ratio Raw RD Raw Ash CSN Calorific Inherent Total Total Value Moisture Moisture Sulphur bcm Tonnes bcm/t t/bcm % MJ/kg % % % % Volatile Matter SCHEDULE 1 1,168, , # ,188, , # ,192, , # ,177, , # ,199, , # ,194, , # ,190, , # ,196, , # , , # , , # , , # #8.17 #34.44 #0.47 #10.03 #0.70 # , , # #8.30 #34.64 #0.49 #10.52 #0.87 # , , # #5.00 #33.96 #1.77 #13.27 #0.55 # , , # #7.83 #34.94 #0.73 #10.58 #0.99 # ,399 76, # #8.54 #34.87 #0.60 #8.47 #0.94 #24.82

10 EMPLACEMENT STRATEGY There are two out of pit ELFs required: Main Lower ELF which holds the majority of the out of pit emplaced material Small Upper ELF which is needed from Year 5 on The Main Lower and Small Upper ELFs eventually form one ELF as they are joined and blended into the in pit back fill material emplaced Swell factor used on all emplaced material is plus 20% of in situ volumes Key drivers in ELF design are to: Minimise impact on high value ecosystems Minimise amount of rehandle The Main Lower ELF includes the ROM pad in the design Emplacement included the ephemeral pond area this allowed the overall ELF footprint to be reduced by having a volume efficient well sized ELF which is kept down hill (out of sight of the reserve) and adjacent to the Brunner pit A replacement ephemeral pond has been built in an area near the original ephemeral pond Paparoa material (non acid forming) is required to be hauled to the Main Lower ELF initially the non acid forming material will be used to line the ELF The ELFs are built from the bottom up following the development of both the Brunner and s and progressing from out of pit to in-pit Rehabilitation is designed to progressively occur each year and follow the progression of the ELFs up hill Approximately 40% of the progressively rehabilitated area will eventually need to be rehandled to allow material to be recovered to fill the final void SCHEDULE

11 FINAL VOID STRATEGY Final void has a volume of 4.9 M cubic metres when compared to original topography and is located in the last strips of the A final rehabilitation surface has been designed taking into account: Return as much of the disturbed area to natural topography where possible Limit final slopes to a maximum slope of not greater than 2:1 (27 degrees) Majority of is returned to original topography (excluding the ridge line which had to be slightly reduced to stay within maximum slope angles of 27 degrees) Remaining has been designed to a slightly lower level from the original topography in order to reduce the amount of rehandle required to fill the final void a reduction of 1.1 M cubic metres has been achieved All overburden that is emplaced and shaped below the ROM pad level does not need to be reshaped This redesigning of final topography landform reduces the rehandle volume required to fill the final void to 3.8 M cubic metres The final void takes approximately 3 years to achieve, with an average of 1.3 M cubic meters being rehandled each year Final rehabilitation of the entire area is expected to take an extra year due to the size required to be rehabilitated The estimated cost to fill the final void is approximately 3.8 M cubic metres at $2.50 per cubic metre giving a cost of approximately $9.5M SCHEDULE

12 MINE SCHEDULE

13 SCHEDULE OUTPUTS The schedule is shown on a year by year basis from two different perspectives: The first sequence is looking to the north east The second sequence is looking due south Each output has the following information highlighted: Access road brown ROM black Topsoil pile brown/maroon Pit and ELF outline purple line MINE SCHEDULE Also shown changing on a year by year basis is: New ELF purple Mining Area brown/orange Final Rehabilitation Area light green Temporary Rehabilitation Area darker green Ridgeline returned to same level as original Bold dashed red line Ridgeline returned to lower level than original Bold dashed blue line Clean water drainage line light blue line Dirty water drainage line dark blue line Clean Dam light blue area Dirty Sumps dark blue area

14 MINE

15 SCHEDULE TOPOGRAPHY AT START Total pit and ELF outline Ridgeline 100m co-ordinate grid N RL E Two pit designs - Brunner and Paparoa pits

16 SCHEDULE YEAR 1 Quarter 1 Main Lower ELF Topsoil Stockpiles New Ephemeral Pond Topsoil Stockpile Ridgeline Diversion drains Pit and ELF outline Paparoa Pit

17 SCHEDULE YEAR 1 Quarter 2 Main Lower ELF Topsoil Stockpiles New Ephemeral Pond Topsoil Stockpile Diversion drains Ridgeline Pit and ELF outline

18 SCHEDULE YEAR 1 Main Lower ELF Topsoil Stockpiles New Ephemeral Pond Topsoil Stockpile Diversion drains Ridgeline Mine Footprint

19 SCHEDULE YEAR 1 Main Lower ELF Topsoil Stockpiles Out of pit sump Diversion drains Ridgeline Mine footprint 100m co-ordinate grid Ridgeline New Ephemeral pond ROM Stockpile In-pit sump

20 Commencement of backfill of Brunner and s SCHEDULE YEAR 2 Main Lower ELF Final Rehabilitation Sump Diversion drains Mine footprint 100m co-ordinate grid Sump New Ephemeral pond ROM Pad

21 SCHEDULE YEAR 3 Main Lower ELF Mine footprint 100m co-ordinate grid New Ephemeral pond

22 SCHEDULE YEAR 4 Main Lower ELF Progresses over Strip 1 of Main Lower ELF In-Pit ELF into Strip 2 Sump Mine footprint 100m co-ordinate grid Temporary Rehabilitation Sump relocated to floor of pit New Ephemeral pond

23 SCHEDULE YEAR 5 Commencement of Small Upper ELF Topsoil Stockpile Mine footprint Ridgeline 100m co-ordinate grid Sump relocated to floor of pit New Ephemeral pond Topsoil Stockpile Commencement of Final Rehabilitation of Paparoa In-Pit ELF

24 Sump relocated on dump SCHEDULE YEAR 6 Mine footprint 100m co-ordinate grid Sump relocated to floor of pit New Ephemeral pond

25 SCHEDULE YEAR 7 In-pit ELF joins Small Upper ELF Mine footprint 100m co-ordinate grid Final Rehabilitation with Lower Ridgeline New Ephemeral pond Sump relocated to floor of pit

26 SCHEDULE YEAR 8 Blending in of temporary rehabilitation of Main Lower ELF, Small Upper ELF and Brunner In-pit ELF Mine footprint 100m co-ordinate grid New Ephemeral pond

27 SCHEDULE YEAR 9 Mine footprint 100m co-ordinate grid RL N North S New Ephemeral pond

28 SCHEDULE YEAR 10 Mine footprint 100m co-ordinate grid New Ephemeral pond

29 SCHEDULE YEAR 11 Contingency ELF capacity located on top of Brunner Pit ELFs Mine footprint 100m co-ordinate grid Completion of New Ephemeral pond

30 SCHEDULE YEAR 12 Emplaced back to natural topography in last strip where doesn t extend underneath Mine footprint 100m co-ordinate grid New Ephemeral pond