ENGINEERING GEOLOGY & GEOTECHNICAL SERVICES

Tel 64 - 3- 546 7425 Email geoquest@geo -logic.co.nz

Web www.geo - logic.co.nz Postal PO Box 880, 17A Examiner Street, Nelson 7015, New Zealand

17019

01 March 2018

Matthew Crawford 393 Pupu Valley Road Takaka 7183 Dear Matthew Geotechnical Site Review; 393 Pupu Valley Road, TAKAKA 1. Scope We were asked to undertake a geotechnical site assessment of a “buffer area” identified by you (and as described in a news story you supplied (www.stuff.co.nz/environment, 16 June 2017) between an area you are proposing for gold mining and the nearby Te Waikoropupu Springs (Pupu Springs) to the east. In your email of 22 December 2017, you advised “A report from Ian Campell has been done in the past, Joseph Tomas has suggested your work may be able to complement Iains to give a clear picture…”. You instructed us to clarify our scope by discussion with the Tasman District Council’s (TDC) Water Resources Analyst Joseph Thomas and this was done in a phone call to Mr Thomas (personal communication, 17 January 2018). We were asked to:

1. Identify the bedrock in the “buffer area” – in particular in the vicinity of the northern extension of a farm track “dogleg” through it. Limited test pitting was suggested.

2. Provide comment on the risk of lateral migration of groundwater through the overburden towards Pupu Springs.

The area is flat lying and currently in pasture and bisected with two farm drains (refer Geotechnical Photo Site Plan, sheet 01 and Photoplate 01). We visited the site completing a reconnaissance walkover of the site and vicinity by an experienced engineering geologist on 19 January 2018. We revisited the site on 16 February 2018, following more favourable weather conditions, completing three test pits to a maximum depth of 2.2m with a 6 tonne track mounted digger (refer Photoplates). We also inspected bedrock exposures to the northeast of the Pupu Springs carpark (Photoplate 7.2).

In addition to the field work undertaken for your project we undertook a desktop review of published geological maps and reports (see references) and reviewed a plethora of information provided by you including:

A Soils Report prepared by Land & Soil Consultancy Services dated 21 July 2017 (Campbell, 2017)

2

Resource Consent Application and AEE prepared by you dated June 2017, with attachments and appendices

TDC Questions and Responses provided 16 January 2018

Borelogs of wells WWD6011 and W6013

We clarified aspects of “Question 6” in our discussion with Joseph Thomas “Could the applicant also confirm if there would be any risk of lateral movement of groundwater in the overlying sediments 

heading towards the springs.”

The area in which we undertook our engineering geological reconnaissance walkover and test pitting is shown on the attached Geotechnical Photo Site Plan, sheet 01.

Our work was undertaken as per an IPENZ Short Form Agreement dated 15 January 2018. The scope of work is limited to that described above and the areal extent of our investigation is as indicated on the Site Plan. Bedrock hydraulic connectivity, mine staging, rehabilitation and soil inventory work was undertaken by others.

2. Geotechnical Setting The geotechnical setting of the area generally is complex. The bedrock geology of the general vicinity is described in the Soils Report (Campbell, 2017) and mapped as being underlain by GRANITE to the north of an unnamed east-west/northeast trending fault and the Onekaka SCHIST on the south side of the fault. The granite is variously indicated as of Lower Cretaceous/ Upper Triassic age in fault contact with older Onekaka Schist of Paleozoic age (Grindley, 1961, 1971). The Pupu Springs area is underlain by considerably younger coarse quartz SANDSTONE and CARBONACEOUS SHALE of the Motupipi Coal Measures of Tertiary age.

Overburden deposits on the valley floor, including the area evaluated in this report, are mapped as Quaternary glacial outwash GRAVELS and ALLUVIAL TERRACE DEPOSITS of the Speargrass Formation, some of which are known to be auriferous (gold bearing). The GRAVELLY ALLUVIAL DEPOSITS observed in the test pits overlying the bedrock consisted of poorly consolidated GRAVEL, SAND and SILT mixtures (GW/GM) which were generally saturated and subject to trench wall collapse.

We encountered CARBONACEOUS SHALE and SANDSTONE, interpreted as Motupipi Coal Measures Bedrock, in the base of each of the three test pits excavated at depths of between 1.4 and 1.8m below ground surface (refer attached graphic and descriptive logs). This is consistent with exposures observed locally in the base of farm drains through the area evaluated and in Fish Creek to the south during our reconnaissance walkover (refer EX-2 and EX-3 on the Geotechnical Site Plan, sheet 01). Bedrock encountered in the test pits was difficult to excavate and effective refusal encountered with a 6 tonne digger at depths of about 2m. The bedding appeared to be flat lying or sub-horizontal.

Bedrock in the Pupu Springs area is Motupipi Coal Measures as observed in a roadcut to the east of the Pupu Spring carpark with a similar shallow dip (070o; 20SE) – refer EX-1 Geotechnical Site Plan, sheet 01and Photoplate 7.2.

Two water well borelogs we were provided with in the area suggest the local thickness of the Motupipi Coal measures is about 12 to 33 metres. Geologic maps of the area suggest a regional thickness of between 300 and 800m. Grindley (1971) describes the schist bedrock to the south of

3

the fault sub-paralleling the nearby Waikoropupu River as overlying the Arthur Marble. This stratigraphic relationship with the Arthur Marble likely provides a sub-regional source/ connectivity for the groundwater source of Te Waikoropupu/ Fish Creek Springs and the recharge area of extensive Arthur Marble exposures on Takaka Hill.

There are no faults mapped through the immediacy of the area evaluated in this report. Geologic maps of the area show an inferred unnamed east-west/northeast trending fault sub-paralleling the Waikoropupu River about 100m to the northwest of the site with the inactive, North-South trending Golden Bay fault about 5km to the west (Grindley, 1961; 1971).

Shallow groundwater was observed in the overburden deposits in each of the three testpits at a depth of about 1.2m with variable inflow (rate and dominate direction/s) observed during test pitting. Bedrock samples recovered were very dense and appeared impermeable. Refer to the Discussion section below for further comments on permeability and shallow groundwater flow.

3. Discussion From discussions with the TDC it is understood that Te Waikoropupu Springs are within the Motupipi Coal Measures which are considered to be impermeable. Council’s request for a geotechnical site review of the “buffer area” by an experienced engineering geologist was sought to:

clarify the boundary between the granite and the coal measure bedrock and seek comment on the risk of lateral migration of groundwater through the overburden

towards Pupu Springs Bedrock Our test pitting and reconnaissance site mapping of bedrock exposures confirm that the “buffer area” is predominately, if not entirely, underlain by Motupipi Coal Measures bedrock. This is supported by the logs of water wells in the area (W6013; WWD6011). The Coal Measures bedrock was everywhere observed to consist of well consolidated, impermeable carbonaceous SHALE, SANDSTONE and CLAYSTONE. We considered extending test pitting to the south of TP -A, B and C and dismissed it based on:

Bedrock continuity identified in the test pits and farm drains., supplemented by bedrock exposures in Fisk Creek

Complexities in obtaining access permission and accurate information on buried water line utilities in the area

Lateral Groundwater Migration Risk We evaluated groundwater flow and the general permeability of overburden deposits encountered in the test pits. The apparently in-situ (i.e. undisturbed) TOPSOIL and SILTY ALLUVIUM overburden (SC/ML/CL), typically about 1 m thick, was damp and, in part owing to the abundant fines (silt and sand), of apparent low permeability. No seepages were observed in these SILTY ALLUVIUM. The likelihood of lateral migration of groundwater through these overburden materials is considered to be “E” Rare with a consequence of Medium to Minor equating to a Low to Very Low overall risk level as per the AGS Appendix C risk matrix. Shallow groundwater was observed in the ALLUVIAL GRAVELS overburden (GW/GM) in each of the three testpits at a depth of about 1.2m with variable inflow (rate and dominate direction/s) observed during test pitting.

4

The thickness of the gravel layer varied in the three test pits from 0.5 to 1.0m – generally increasing to the east. These materials appear to be permeable being saturated and generally free draining. Groundwater seepages characteristics varied in each of the three test pits:

A. In TP-A the primary inflow appeared to be from the south with apparent minor backflow (?) of groundwater from the northeast. About an hour after the test pit was opened the groundwater level appeared to “settle” at about 1.3m below ground level (refer graphics log; Photoplate 3.2)

B. In TP-B similar (albeit slower than in TP-A) backflow (?) inflow was observed from all sides of the trench. The standing water level in a nearby farm drain to the north was measured at about 1.2m below ground level.

C. In TP-C similar (albeit slower than in TP-B, i.e the slowest observed) backflow (?) inflow was observed from the north and south trench walls.

In general, we observed an apparent decrease in the apparent shallow groundwater flow volumes to the north and east in the three testpits. Groundwater levels are likely to fluctuate seasonally. Surface (farm drain) flow was observed to be to the north and northeast towards Waikoropupu River. Variable shallow groundwater seepage was observed in the ALLUVIAL GRAVELS overlying apparently impermeable bedrock. The likelihood of lateral migration of groundwater through these overburden materials towards Pupu Springs is considered to be “C/D” possible/unlikely with a consequence of Medium to Minor equating to a Moderate to Low overall risk level. This risk can be effectively reduced by careful management and drainage control during mining and subsequent reinstatement in the proposed mining areas to the west thereby reducing the overall risk level to Low to Very Low as per the AGS Appendix C Risk Matrix. Geotechnical Suitability We are satisfied that the work undertaken for this report adequately defines the geotechnical character and setting of the ground conditions between the propose mining area and Te Waikoropupu Springs – the “buffer area”. On the basis of the interpretation and conclusions presented above, and for the reasons presented in the Answer to Question 6 (refer paragraph 3), we believe the proposed “buffer area”, when managed properly/ as intended is geotechnically appropriate for the intended use. The current Moderate to Low overall risk level of lateral migration of groundwater through the ALLUVIAL GRAVEL overburden materials towards Pupu Springs can be effectively reduced by careful management and drainage control during mining and subsequent reinstatement in the proposed mining areas to the west thereby reducing the overall risk level to Low to Very Low.

4. Conclusions and Recommendations

1. The geotechnical setting of the area generally is complex.

2. We encountered CARBONACEOUS SHALE and SANDSTONE, interpreted as Motupipi Coal Measures Bedrock, in the base of each of the three test pits excavated at depths of between 1.4 and 1.8m below ground surface.

3. The ALLUVIAL GRAVEL observed in the test pits overlying the bedrock consisted of

poorly consolidated GRAVEL, SAND and SILT mixtures which were generally saturated and subject to trench wall collapse.

5

4. Shallow groundwater was observed in the ALLUVIAL GRAVEL overburden in each of

the three testpits at a depth of about 1.2m with variable inflow (rate and dominate direction/s) observed during test pitting.

5. The apparently in-situ TOPSOIL and SILTY ALLUVIUM overburden, typically about 1

m thick, was damp and of apparent low permeability and no seepages were observed.

6. The likelihood of lateral migration of groundwater through SILTY ALLUVIUM overburden materials is considered to be “E” Rare with a consequence of Medium to Minor equating to a Low to Very Low overall risk level.

7. The likelihood of lateral migration of groundwater through the ALLUVIAL GRAVEL

overburden materials towards Pupu Springs is considered to be “C/D” possible/unlikely with a consequence of Medium to Minor equating to a Moderate to Low overall risk level.

8. This risk can be effectively reduced by careful management and drainage control during

mining and subsequent reinstatement in the proposed mining areas to the west thereby reducing the overall risk level to Low to Very Low.

9. The current Moderate to Low overall risk level of lateral migration of groundwater

through the ALLUVIAL GRAVEL overburden materials towards Pupu Springs can be effectively reduced by careful management and drainage control during mining and subsequent reinstatement in the proposed mining areas to the west thereby reducing the overall risk level to Low to Very Low.

10. We believe the proposed “buffer area”, when managed properly/ as intended is

geotechnically appropriate for the intended use.

5. Limitations

This report is confidential and has been prepared solely for the benefit of the Matthew Crawford, the TDC and his designees. No liability is accepted by this firm, in respect of its use by any other person. Any other person who relies upon any matter contained in this letter without consultation with and agreement by Geo-Logic Limited as to its applicability to that persons intentions, does so entirely at their own risk. This disclaimer shall apply notwithstanding that the letter be made available to any person in connection with any application for permission or approval, or pursuant to any requirement of law. The scope of work is limited to that described above and the areal extent of our investigation is as indicated on the Site Plan. Bedrock hydraulic connectivity, mine staging, rehabilitation and soil inventory work was undertaken by others.

This report must be reviewed for applicability in the event that any substantial modifications are made to the site or adjacent properties such that site conditions are changed substantially from current site conditions.

6

6. References AUSTRALIAN GEOMECHANICS SOCIETY, 2007: Practice Note Guidelines for Landslide Risk Management 2007. Australian Geomechanics Journal Vol 42 No 1 March 2007

CAMPBELL, I 2017: Report on Resource Consent Application for gold mining-Pupu valley Road, Takaka. Soils report prepared by Land & Soil Consultancy Services for Matthew Crawford dated 21 July 2017

GRINDLEY, G W 1961: Sheet 13 - Golden Bay, Geological Map of New Zealand, 1:250000

GRINDLEY, G W, 1971: Sheet S8 Takaka. Geological Map of New Zealand, 1:63,360. NZ Department of Scientific and Industrial Research, Wellington

NEW ZEALAND GEOTECHNICAL SOCIETY, 2005. Field Description of Soil & Rock - Guideline for the Field Classification and Description of Soil and Rock for Engineering Purposes”

RATTENBURY, M S; COOPER, R A; JOHNSTON, M R, 1998: Geology of Nelson Area. Prepared by the Institute of Geological and Nuclear Sciences 1:250 000 geological map. Lower Hutt New Zealand

https://www.stuff.co.nz/environment/93680989/gold-miner-backtracks-on-plans-to-mine-next-to-te-waikoropupu-springs

Yours faithfully

GEO-LOGIC LIMITED

Paul C Denton Engineering Geologist

Attachments: Geotechnical Photo Site Plan sheet 01 Photoplate 01 Site Overviews Photoplate 02 Test Pit A 01 of 02 Photoplate 03 Test Pit A 02 of 02 Photoplate 04 Test Pit B 01 of 02 Photoplate 05 Test Pit B 02 of 02 Photoplate 06 Test Pit C Photoplate 07 TP C and EX-1 Graphic Trench Log – TP-A Descriptive Log – TP-B Descriptive Log – TP-C Soil Exploration Terminology AGS Appendix C – Qualitative Risk Analysis Matrix, Practice Note

393 Pupu Valley Road Geo Review Report01 FINAL

PCD Matthew CrawfordGeotechnical Site Review

393 Pupu Valley RoadTAKAKA

GEOTECHNICALPHOTO SITE PLAN

SHEET 01

JASPCD

-- 1:5,000; 1:50,000 (A3)

26 February 2018G17019Splan01.mxd

17019 REV

CONCEPTUAL Project site

StatusDateFileProject #

Scales

Approved

DesignedDrawn

DATEAMENDMENTS INITREV

Surveyed

LOCATION MAP (3)

º

ENGINEERING GEOLOGY &GEOTECHNICAL SERVICES

64-3-546 7425 64-3-546 7208 geoquest@geo-logic.co.nzPO Box 880, Nelson 7015, New Zealand

Tel FaxEmail

SCALE (A3)

GEO-LOGICL I M I T E D

1:50,0000 2 km

A

A

A

A_

_

_

?

?

?

?

?

?

?

?

?

?

?

?

ª

ª

ª

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!H

!H

¿

¿

¿

W a i k o r o p u p u Ri v

e rPupu Valley Road

Fish C

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Fish CreekSprings

Pupu Valley Road

EX-1

20Te Waikoropupu Springs

SalmonFarm

EX-2

EX-3

6

5

3

TP-C

W6013

WWD6011

4

TP-B

TP-A

NOTES:(1) Approximate location (ie not surveyed)(2) Refer to discussion in text(3) Cadastral Information source from LINZ data, extracted 7 September 2010. Crown Copyright Reserved.Aerial base extracted from www.topofthesouthmaps.co.nzFebruary 2018

LegendTest pit(1)

Test pit by others(1),(2)

Existing water well(1),(2)

Spring(1)

Farm drain showing direction of drainageBedrock exposure(1)

Bedding orientation (strike and dip)Proposed mining areaVERY APPROXIMATE EXTENT(1),(2)

_ TP-C

A 6!H

? ?

ª EX-3o20

º

SCALE (A3)1:5,000

0 200100 m

Matthew Crawford

Geotechnical Site Review

393 Pupu Valley Road

Takaka, Golden Bay

17019

1.1 Overview of area evaluated. Main Pupu Springs in distance at far right. View looking north west.

1.2 Area evaluated vicinity of farm track ‘dogleg’. View looking north.

Photoplate 01 Site Overviews

Matthew Crawford

Geotechnical Site Review

393 Pupu Valley Road

Takaka, Golden Bay

17019

2.1 TP-A underway west of ‘dogleg’. View looking northeast.

2.2 TP-A excavation. East wall profile.

Photoplate 02 Test Pit A 01 of 02

Matthew Crawford

Geotechnical Site Review

393 Pupu Valley Road

Takaka, Golden Bay

17019

3.1 TP-A Shallow groundwater inflow shortly after excavation (16 February 2018).

3.2 TP 1 Groundwater 1 hour after excavation (1.3m below ground surface).

Photoplate 03 Test Pit A 02 of 02

Matthew Crawford

Geotechnical Site Review

393 Pupu Valley Road

Takaka, Golden Bay

17019

4.1 TP-B underway east of ‘dogleg’. View looking northeast.

4.2 TP-B underway. View looking north.

Photoplate 04 TP – B 01 of 02

Matthew Crawford

Geotechnical Site Review

393 Pupu Valley Road

Takaka, Golden Bay

17019

5.1 TP-B excavation. North wall profile. Shallow groundwater seepage @ 1.2m

below ground surface.

5.2 TP-B excavation. Tail wall profile. Looking west.

Photoplate 05 TP – B 02 of 02

Matthew Crawford

Geotechnical Site Review

393 Pupu Valley Road

Takaka, Golden Bay

17019

6.1 TP-C underway in distance. Visible is stake marking TP-A in foreground. View

looking northeast. Pupu Springs off to right.

6.2 TP-C underway. View looking north.

Photoplate 06 Test Pit C

Matthew Crawford

Geotechnical Site Review

393 Pupu Valley Road

Takaka, Golden Bay

17019

7.1 TP-C Excavation showing slow groundwater seepage at bedrock interface @ 1.8m.

7.2 Motupipi Coal Measures exposed along Pupu Springs Road EX-1 (refer site

plan sheet 01for location).

Photoplate 07 TP – C and EX - 1

\GENERAL standards\FORMS\Graphic Trench Log (field form).pub

A1 Sample @ 0.5m

A2 Sample @ 0.8m A3 Sample @ 1.3m A4 Sample @ 1.6m

TOPSOIL: Medium gray CLAYEY SILT / SILTY CLAY (CL/ML); damp; moderate plasticity; roots & rootlets. SILTY ALLUVIUM I: Blue gray brown CLAYEY SILT (SC/ML): damp; low to moderate plasticity; low permeability; rootlets. SILTY ALLUVIUM II: Yellow brown SANDY CLAY / CLAYEY SILT (SC/CL); as above w/ more Fine sand. GRAVELLY ALLUVIUM: Reddish brown SAND SILT GRAVEL MIX (GM): wet to Saturated below about 1.2m; poorly consolidated w/ abundant surrounded gravels to 150mm; preserved tree roots; permeable-primary go inflow from south. BEDROCK: (Motupipi Coal Measures) Dark glay to black CARBONACEOVS SANDSTONE w/ mini coal stringers; very dense; very low permeability (difficult digging) apparently flat lying.

1

2 3 4 5

0.0 - 0.2

0.2 - 0.6

0.6 - 0.9 0.9 - 1.4

1.4 - 1.9

Sheet 01 of 01

SCALE:

BEARING:

LOOKING:

0

SCALE

GRAPHIC TRENCH LOG

DEPTH (E.L.)

Date Logged: 16 February 2018 Notes: Refer photoplates 02 and 03

M Crawford Geotechnical Investigation

393 Pupu Valley Road, Takaka, Golden Bay

TRENCH # TP- A Excavation Equipment: 6 Tonne Tracked Digger

Trench Width (m): 0.6m

Project Number/Name: 17019 / Geo Review

Geologist/Engineer: PC Denton

Depth No. Description Type Dip Strike No.

STRUCTURE UNITS

BEARING:

LOOKING:

0.5 m

338°

North

4 2 0

1.3m after 1hour

1

2

3

4

5

. . . . . . . . .--__ -- __ ---__ ---- _ ------ _ .. . . . . . . . .

. . . . . . . . .-- __ -- __ ---__

. . . . . . . . .--__ -- __ ---__ ---- _ ------ _ .. . . . . . . . .

A1

A2

A3

A4

\GENERAL standards\FORMS\Terminology for Descript of Soils.pub

INCLINATION (from the

horizontal)

TERM BED THICKNESS

Very thick >2 m

Sub horizontal 0 - 10° Thick 600 - 2 m

Gently inclined 10° - 30° Moderately thick

200 - 600 mm

Moderately inclined 30° - 60°

Moderately thin 60 - 200 mm

Thin 20 - 60 mm

Steeply inclined 60° - 80°

Very thin 6 - 20 mm

Laminated 2 - 6 mm

Sub vertical 80° - 90° Thinly laminated <2 mm

TERM

TERM DIAGNOSTIC FEATURES UNDRAINED COMPRESSIVE

STRENGTH (kPa)

Very soft Exudes between fingers when squeezed

< 25

Soft Easily indented by fingers 25 - 50

Firm Indented only by strong finger pressure

50 - 100

Stiff Indented by thumb pressure 100 - 200

Very stiff Indented by thumbnail 200 - 400

Hard Difficult to indent by thumbnail 400 - 1000

TERM % OF SOIL MASS EXAMPLE

SUBORDINATE FRACTION (….)Y 20 - 50 SANDY

MAJOR FRACTION

…. - …. 35 - 50 SAND - GRAVEL

.... major constituent GRAVEL

with trace of <5 with a trace of sand

with minor 5 - 12 with minor sand

with some 12 - 20 with some sand

MINOR FRACTION

4. PLASTICITY Plasticity of clays and silts is determined from the results of Atter-berg limit tests. In the field the characteristics of fine grained soils are identified using dilatancy (reaction to shaking), dry strength (crushing) and toughness (consistency near the plastic limit) behav-ior - see USBR chart. The most characteristic test of plasticity in a soil is dilatancy where on rapid shaking water appears and similar shaking gives no reaction for a plastic soil. 5. GRADING QUALIFICATIONS The grading of gravels and sands may be qualified in the field as well graded (i.e. good representation of all particle sizes from largest to smallest) or poorly graded. Poorly graded materials may be fur-ther divided into uniformly graded (i.e. most particles about the same size) and gap graded (i.e. absence of one or more intermedi-ate sizes). 6. WEATHERING Weathering of soils is more relevant to coarse grained soils and where weathering does not have an influence on the properties of a soil the term may be omitted. 7. BEDDING Bedding Inclination Terms

3. MOISTURE CONDITION

Proportions

1. SOIL NAME For coarse grained soils (>65% sand and gravel) the soil name is based on the particle sizes present. For fine grained soils (>35% silt and clay sizes) it is based on behavioral characteristics of remould-ing. Particle sizes

Sheet 01 of 02

Reference: NZ Geotechnical Society Inc “Field Description of Soil and Rock” December 2005

SOIL TERMINOLOGY DESCRIPTION SHEET

TERMINOLOGY FOR DESCRIPTION OF SOILS IN THE FIELD

Loosely packed

− can be removed from exposure by hand or removed easily by shovel.

Tightly packed

− requires pick for removal, either as lumps or as dis-aggregated material.

A visual assessment is based on

Dry − Soil looks and feels dry; cohesive soils usually hard, powdery or friable while granular soils run freely through hands.

Moist − Soil feels cool, darkened in colour; granular soils tend to cohere while cohesive soils usually weak-ened by moisture presence, but one gets no free water on hands when remoulding.

Wet − Soil feels cool, darkened in colour, granular soils tend to cohere, while cohesive soils usually weak-ened and free water forms on hands when handling.

Saturated − Soil feels cool, darkened in colour and free water is present on the sample. Fully saturated refers to the case where the soil is below the water table.

b) Coarse-grained soils

8. PARTICLE SHAPE Roundness Terms

Rounded Angular Sub rounded Sub angular

Fine grained soils are silt (M) or clay (C) based on whether they plot below or above the A-line on a Casagrande chart. The boundary between ‘lean’ (L) or ‘fat’ (H) for either a silt or clay is at a liquid limit of 50 eg CL MH. 2. STRENGTH a) Fine-grained soils (cohesive)

>200 mm very coarse gravel 60-200 mm

gravel

coarse 20-60 mm

sand

coarse 0.6-2.0 mm

medium 6-20 mm medium 0.2-0.6 mm

fine 2- 6 mm fine 0.06-0.2 mm

silt 2-60µ clay <2µ

boulders

\GENERAL standards\FORMS\Unified Soil Classification.pub

Reference: Figure 7, Unified Soil Classification Chart (drawing 103-D-347), Earth Manual; US Department of the Interior, 1974

SA

ND

S W

ITH

FI

NE

S

(App

reci

able

am

ount

of

fine

s)

GR

AV

ELS

WIT

H

FIN

ES

(A

ppre

ciab

le a

mou

nt

of fi

nes)

Slight to medium

Clayey sands, poorly graded sand-clay mixtures.

Organic silts and organic silt-clays of low plasticity.

DILATANCY (REACTION TO

SHAKING)

GM

Sheet 02 of 02

FIELD IDENTIFICATION PROCEDURES (Excluding particles larger than 3 inches and basing fractions on estimated weights)

GROUP SYM-BOLS

ς

TYPICAL NAMES

GW

CH

OH

Pt

GP

SP

SM

SC

GC

MH

OL

CL

ML

SW

Well graded gravels, gravel-sand mixtures, little or no fines.

Poorly graded gravels, gravel-sand mixtures, little or no fines.

Silty gravels, poorly graded gravel-sand-silt mixtures.

Clayey gravels, poorly graded gravel-sand-clay mixtures.

Well graded sands, gravelly sands, little or no fines.

Poorly graded sands, gravelly sands, little or no fines.

Silty sands, poorly graded sand-silt mixtures.

Inorganic silts and very fine sands, rock flour, silty or clayey fine sands with slight plasticity.

Inorganic clays of low to medium plasticity, grav-elly clays, sandy clays, silty clays, lean clays.

Inorganic silts, micaceous or diatomaceous fine sandy or silty soils, elastic silts.

Inorganic clays of high plasticity, fat clays.

Organic clays of medium to high plasticity.

Peat and other highly organic soils.

Wide range in grain size and substantial amounts of all intermediate particle sizes.

Predominantly one size or a range of sizes with some intermediate sizes missing.

Non-plastic fines (for identification procedures see ML below).

Plastic fines (for identification procedures see CL below).

Wide range in grain size and substantial amounts of all intermediate particle sizes.

Predominantly one size or a range of sizes with some intermediate sizes missing.

Non-plastic fines (for identification procedures see ML below).

Plastic fines (for identification procedures see CL below).

DRY STRENGTH (CRUSHING

CHARACTERISTICS)

None to slight

HIGHLY ORGANIC SOILS Readily identified by color, odor, spongy feel and frequently by fibrous texture.

Medium to high

High to very high

Slight to medium

Slight to medium

Medium to high

Coa

rse

GR

AIN

ED

SO

ILS

M

ore

than

hal

f of m

ater

ial i

s la

rger

than

No.

200

sie

ve s

ize.

FI

NE

GR

AIN

ED

SO

ILS

M

ore

than

hal

f of m

ater

ial i

s sm

alle

r tha

n N

o. 2

00 s

ieve

siz

e.

GR

AV

ELS

M

ore

than

hal

f of c

oars

e fra

ctio

n is

la

rger

than

No.

4 s

ieve

siz

e.

SA

ND

S

Mor

e th

an h

alf o

f coa

rse

fract

ion

is

smal

ler t

han

No.

4 s

ieve

siz

e.

CLE

AN

GR

AV

ELS

(L

ittle

or n

o fin

es)

CLE

AN

SA

ND

S

(Litt

le o

r no

fines

)

SIL

TS A

ND

CLA

YS

Liqu

id li

mit

less

than

50

SIL

TS A

ND

CLA

YS

Liqu

id li

mit

grea

ter t

han

50

IDENTIFICATION PROCEDURES ON FRACTION SMALLER THAN No. 40 SIEVE SIZE

Quick to slow None

None to very slow Medium

Slow Slight

Slow to none

None High

None to very slow

Slight to medium

TOUGHNESS (CONSISTENCY

NEAR PLASTIC LIM.)

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SOIL TERMINOLOGY DESCRIPTION SHEET

UNIFIED SOIL CLASSIFICATION

PRACTICE NOTE GUIDELINES FOR LANDSLIDE RISK MANAGEMENT 2007 APPENDIX C: – QUALITATIVE TERMINOLOGY FOR USE IN ASSESSING RISK TO PROPERTY (CONTINUED)

QUALITATIVE RISK ANALYSIS MATRIX – LEVEL OF RISK TO PROPERTY

LIKELIHOOD CONSEQUENCES TO PROPERTY (With Indicative Approximate Cost of Damage) Indicative Value of

Approximate Annual Probability

1: CATASTROPHIC 200%

2: MAJOR 60%

3: MEDIUM 20%

4: MINOR 5%

5: INSIGNIFICANT

0.5% A – ALMOST CERTAIN 10-1 VH VH VH H M or L (5)

B - LIKELY 10-2 VH VH H M L

C - POSSIBLE 10-3 VH H M M VL

D - UNLIKELY 10-4 H M L L VL

E - RARE 10-5 M L L VL VL

F - BARELY CREDIBLE 10-6 L VL VL VL VL

Notes: (5) For Cell A5, may be subdivided such that a consequence of less than 0.1% is Low Risk. (6) When considering a risk assessment it must be clearly stated whether it is for existing conditions or with risk control measures which may not be implemented at the current

time.

RISK LEVEL IMPLICATIONS

Risk Level Example Implications (7)

VH VERY HIGH RISK Unacceptable without treatment. Extensive detailed investigation and research, planning and implementation of treatment options essential to reduce risk to Low; may be too expensive and not practical. Work likely to cost more than value of the property.

H HIGH RISK Unacceptable without treatment. Detailed investigation, planning and implementation of treatment options required to reduce risk to Low. Work would cost a substantial sum in relation to the value of the property.

M MODERATE RISK May be tolerated in certain circumstances (subject to regulator’s approval) but requires investigation, planning and implementation of treatment options to reduce the risk to Low. Treatment options to reduce to Low risk should be implemented as soon as practicable.

L LOW RISK Usually acceptable to regulators. Where treatment has been required to reduce the risk to this level, ongoing maintenance is required.

VL VERY LOW RISK Acceptable. Manage by normal slope maintenance procedures.

Note: (7) The implications for a particular situation are to be determined by all parties to the risk assessment and may depend on the nature of the property at risk; these are only given as a general guide.

92 Australian Geomechanics Vol 42 No 1 March 2007

Report on Resource Consent Application for gold mining-Pupu

Valley Road, Takaka

Dr Iain Campbell

Land & Soil Consultancy Services

46 Somerset Terrace

Stoke, Nelson 7011

21 July 2017

Outline of Geology, water and soil resources of the area

Geology

Waikoropupu Valley broadly follows a line that separates Onahau Granite, outcropping on the north and southwest part of the valley from Onekaka Schist rocks on the southern side (Figure 1). The two formations are separated by a fault that passes 0.5km west of Pupu Spring. The bed of the Waikoropupu River is predominantly on the Onahau Granite Formation, as seen in numerous places along the river course, and the valley floor gravel appears to be everywhere underlain by the basement-forming Onahau Granite, which probably confines drainage waters within the valley. The main valley floor is made up of Late Last glaciation alluvium, comprising coarse bouldery (gold bearing) gravels on top of the granite bedrock. The coarse bouldery nature of the gravels is indicative of past massive fluvial outflows, perhaps resultant from glacial outwash. The gravels are of variable thickness, in places less than 1m, and are overlain by finer textured soil forming sediments ranging from 40-200cm thick, as seen in the pits. At two sites (2 & 9) the surface sediments are of more recent age. At the western end of the property, terrace remnants are up to about 10m above the valley floor and indicate an earlier period of outwash accumulation with similar coarse gravel alluvium present that also overlies the granite bedrock.

Water Resources

Waikoropupu River is a relatively fast flowing stream with a fall of approximately 10m/km. The river sediments are predominantly coarse gravels, similar to those underlying the soils over the property at 393 Pupu Valley Road. Granite outcrops exposed along the river bank and in the river bed indicate that the river is predominantly flowing along the granite basement bedrock, or on and within a thin cover of bouldery gravel.

Adjacent to the river, examination pits ( Figure 2 pits 2 and 3) had significant water inflows, the base of the pits being similar to that of granite outcrops in the river. Site

5 away from the river but adjacent to a drain also had a significant water inflow. Mining in areas adjacent to the river is unlikely to have any effect on the river flow because the granite basement is at a similar depth to that in the river and the water flowing through the gravel is part of the valley hydrological system.

Because of the proximity of the granite bedrock to the surface, as seen in the river and in excavated pits, mining below the river bed depth is unlikely. A minimal setback from the river may therefore be all that is required.

Water was also observed in other test pits (Figure 2 pits 4, 6, 7, 9 &10) and inflow rates were variable. In test pits 1, 8, 11, 12 & 13 no water present at the excavated depth.

The potential for flooding is limited and based on layered sediments in the soil, was only evident at sites 2 & 9. Prevention of flooding could be achieved by emplacement of temporary stop banks, using soil material excavated prior to mining.

If waters from sluicing operations are discharged within the mining excavation pits, there should be little or no effect on the river waters, as any fine sediment would be expected to be filtered within the gravels as water passes back into the river hydrological system.

As Waikoropupu River is flowing on granite bedrock and as the bed level to the west of Pupu Spring is very close to that of the up welling water level at the spring, there is unlikely to be any hydrological connection between Waikoropupu River and Pupu Spring.

Soil resources

A range of soils occur within the application area and they vary in respect of their depth, drainage and age related properties.

Anthropic soils Anthropic soils were noted at two sites, pits 1, & 13 and are soils that are a consequence of human activity (previous mine tailings). They have lost their original form since no rehabilitation of their initial features was undertaken. At pit 1 a thin topsoil overlies brown stony tailings subsoil (80cm thick), this having been placed on an undisturbed previous soil (with its retained original topsoil) then passing into coarse gravel at 2.20m. At pit site 13 a thin topsoil overlies brown stony tailings (60cm) which in turn overlies undisturbed bouldery gravel with intermittent thin iron accumulations and in turn overlies compact silty sand with some iron enrichment. The Fe accumulations are probably a result of intermittent lateral water movement through the lower materials. Mining within areas that have been previously disturbed is unlikely to have any detrimental effect on productive capacity and may be beneficial if some fine earth material is replaced at the surface during land restoration.

Takaka soils Takaka soils are soils formed from recently deposited alluvium (pits 2 & 9) and are of somewhat limited extent. At pit 2 multiple flood layering is indicated by several bands of darker coloured buried topsoil and 1.30m of fine earth material overlies

bouldery gravel with Fe accumulations. At pit 9, recent flood alluvium overlies some earlier tailings. Inundation with flood waters while mining in these areas could be avoided by using overburden to construct temporary stop banks.

Ikamatua and Puramahoi soils Ikamatua and Puramahoi soils (pits 3, 4, 6, 10) are soils on older alluvial deposits on more elevated flood free surfaces. These are predominantly well drained soils with an observed thickness of silt loam/sandy loam soil overburden between 0.9 and 1.8m. Because of their deeper and well drained profiles, they are considered to be the soils with the highest productive capacity on the property.

Tukurua and Paton soils Tukurua and Paton soils (pits 5, 7,8) are soils that are moderately well drained to imperfectly drained, their subsoils being effected by the effects of higher groundwater or slow drainage through heavier textured subsurface sediments. At pit 5, groundwater was present at 80cm. The soil at pit 8 is complex, the upper 30cm having formed through the addition of recent sediment from adjacent gully erosion while deeper horizons have some Fe accumulation and have drainage restrictions. No gravel was present within 2.2m in this pit. Removal and replacement of these soils would need to be undertaken in drier conditions to avoid soil compaction.

Onahau soils Onahau soils (pit11) are confined to a restricted area at the west of the property and are occur on an older terrace level. Because of the greater surface age, the soil has developed podzolic features which includes a pale grey subsurface horizon below which is a dark coloured humus/iron pan (not strongly cemented) overlying somewhat weathered partly oxidised gravels. The humus/iron pan is sufficiently developed to restrict the downward movement of water and mining of this area would destroy the iron cemented horizon and result in improved soil drainage. Sluicing would however give rise to higher amounts of fine sediment sowing to the oxidised and partly weathered nature of the subsurface gravels.

Staging of works

Because there are a variety of soils on the property with differing soil/hydrological attributes, it would be appropriate to very selective about where and when differing areas should be worked. Areas with impeded subsurface drainage, for example should only be worked in the driest conditions.

Land Rehabilitation

1 In order to achieve the best possible outcome for productive use of the land

after mining, at any one time, the working area should be kept as small as practically

possible. This is to avoid excessive stockpiling of the topsoil and minimise structural

damage to the soil materials while being stored and during the process of their

successive replacement.

2 The dark brown topsoil (depth approximately 25-30cm) should be separately

removed and stored in piles not more than 1m high followed by the yellowish brown

subsoil (which is of variable thickness) and likewise stored separately.

3 Removal of the topsoil and subsoil should be in strips, by means of a digger

working from the undisturbed land surface to avoid compacting the subsoil material

during its removal.

4 Topsoil and subsoil material should not be removed or replaced at any time

when the soil condition can be described as very moist or wet and is best done under

drier conditions, in order to avoid soil compaction and loss of soil structure. This will

be especially important in the areas that have soil drainage limitations (moderately

well drained to imperfectly drained soils). In areas that have been previously mined

and where the soils are gravelly, the soil moisture condition is off lesser importance.

5 A method will need to be established for replacing the subsurface gravel once

mining has taken place. For the most part, it appears from the pits that the gravel

deposits are relatively thin, so re-spreading should not be difficult. The replaced

gravel may be at a slightly higher finished level owing to a change in the density of

the gravel because of its disturbance. However, since the gravel deposits for the

most part does not appear to be thick, there may not be a significant change in

volume. Fines from the washing can be incorporated back into the gravel but should

be mixed with the gravel and not placed in layers.

6 The surface of the replaced gravel should be smoothed using tracked machinery

and the surface materials (topsoil and subsoil) similarly smoothed with tracked

machinery. The land should be graded in a systematic way to facilitate gentle runoff

and avoid ponding in periods of excessive rainfall. It may be useful to establish

benchmarks, to ensure that a satisfactory land surface configuration is achieved

when the operation is completed.

7 If the area of open ground is kept small, as the operation proceeds a worthwhile

objective would be to replace the removed subsoil and topsoil directly back onto the

restored gravel surface without the need for double handling or extensive stockpiling

of either the topsoil or the subsoil.

8 No foreign soil material should be introduced into the mining area.

9 In areas where the watertable is high (pit site 7) the provision of subsurface

drainage would be beneficial.

10 Restored areas should be sown with appropriate seed and fertiliser with regard

to the expected use of the land following mining.

Figure 1. Geological map of the area

Figure 2 Test pit sites

Figures 3-15 Investigation pit sites and summary of soil materials

888

Pit site 1 Soil Anthropic-well drained Material Tailings/Ikamatua soil/gravel Overburden 2.2m Basement not seen Water not present

Pit site 2 Soil Takaka-well drained Material alluvium/buried soil/gravel Overburden 1.3m Basement granite Water groundwater inflow

Pit site 3 Soil Puramahoi-well drained Material silty alluvium/gravel Overburden 1.1m Basement granite Water groundwater inflow

Pit site 4 Soil Puramahoi-well drained Material silty alluvium/gravel Overburden 0.9m Basement granite Water groundwater inflow

Pit site 5 Soil Tukurua-mod well drained Material silty alluvium/gravel Overburden 0-6m Basement granite Water groundwater inflow

Pit site 6 Soil Ikamatua/well drained Material silty alluvium/gravel Overburden 1.2m Basement granite Water groundwater inflow Basement granite Water groundwater inflow

Pit site 7 Soil Paton-imperfectly drained Material silty alluvium/gravel Overburden 1.2m Basement granite Water groundwater inflow

Pit site 8 Soil Paton-imperfectly drained Material silty alluvium Overburden 2m Basement sandy Water nil

Pit site 9 Soil Takaka/Anthropic-well dr Material silty alluvium/tailings/gravel Overburden 0.4m Basement granite? Water groundwater inflow

Pit site 10 Soil Puramahoi-well drained Material silty alluvium/gravel Overburden 1.8m Basement granite Water small groundwater inflow

Pit site 11 Soil Onahau/imp drained Material silty alluvium with Fe pan Overburden 0.7m Basement granite Water nil

Pit site 12 Soil Ikamatua-well drained Material silty alluvium Overburden 2.2m Basement granite Water nil

Pit site 13 Soil Anthropic-well drained Material stony alluvium/silty sand Overburden 0.6m Basement sandy Water nil

Report on Resource Consent Application for gold mining-Pupu

Valley Road, Takaka

Dr Iain Campbell

Land & Soil Consultancy Services

46 Somerset Terrace

Stoke, Nelson 7011

21 July 2017

Outline of Geology, water and soil resources of the area

Geology

Waikoropupu Valley broadly follows a line that separates Onahau Granite, outcropping on the north and southwest part of the valley from Onekaka Schist rocks on the southern side (Figure 1). The two formations are separated by a fault that passes 0.5km west of Pupu Spring. The bed of the Waikoropupu River is predominantly on the Onahau Granite Formation, as seen in numerous places along the river course, and the valley floor gravel appears to be everywhere underlain by the basement-forming Onahau Granite, which probably confines drainage waters within the valley. The main valley floor is made up of Late Last glaciation alluvium, comprising coarse bouldery (gold bearing) gravels on top of the granite bedrock. The coarse bouldery nature of the gravels is indicative of past massive fluvial outflows, perhaps resultant from glacial outwash. The gravels are of variable thickness, in places less than 1m, and are overlain by finer textured soil forming sediments ranging from 40-200cm thick, as seen in the pits. At two sites (2 & 9) the surface sediments are of more recent age. At the western end of the property, terrace remnants are up to about 10m above the valley floor and indicate an earlier period of outwash accumulation with similar coarse gravel alluvium present that also overlies the granite bedrock.

Water Resources

Waikoropupu River is a relatively fast flowing stream with a fall of approximately 10m/km. The river sediments are predominantly coarse gravels, similar to those underlying the soils over the property at 393 Pupu Valley Road. Granite outcrops exposed along the river bank and in the river bed indicate that the river is predominantly flowing along the granite basement bedrock, or on and within a thin cover of bouldery gravel.

Adjacent to the river, examination pits ( Figure 2 pits 2 and 3) had significant water inflows, the base of the pits being similar to that of granite outcrops in the river. Site

5 away from the river but adjacent to a drain also had a significant water inflow. Mining in areas adjacent to the river is unlikely to have any effect on the river flow because the granite basement is at a similar depth to that in the river and the water flowing through the gravel is part of the valley hydrological system.

Because of the proximity of the granite bedrock to the surface, as seen in the river and in excavated pits, mining below the river bed depth is unlikely. A minimal setback from the river may therefore be all that is required.

Water was also observed in other test pits (Figure 2 pits 4, 6, 7, 9 &10) and inflow rates were variable. In test pits 1, 8, 11, 12 & 13 no water present at the excavated depth.

The potential for flooding is limited and based on layered sediments in the soil, was only evident at sites 2 & 9. Prevention of flooding could be achieved by emplacement of temporary stop banks, using soil material excavated prior to mining.

If waters from sluicing operations are discharged within the mining excavation pits, there should be little or no effect on the river waters, as any fine sediment would be expected to be filtered within the gravels as water passes back into the river hydrological system.

As Waikoropupu River is flowing on granite bedrock and as the bed level to the west of Pupu Spring is very close to that of the up welling water level at the spring, there is unlikely to be any hydrological connection between Waikoropupu River and Pupu Spring.

Soil resources

A range of soils occur within the application area and they vary in respect of their depth, drainage and age related properties.

Anthropic soils Anthropic soils were noted at two sites, pits 1, & 13 and are soils that are a consequence of human activity (previous mine tailings). They have lost their original form since no rehabilitation of their initial features was undertaken. At pit 1 a thin topsoil overlies brown stony tailings subsoil (80cm thick), this having been placed on an undisturbed previous soil (with its retained original topsoil) then passing into coarse gravel at 2.20m. At pit site 13 a thin topsoil overlies brown stony tailings (60cm) which in turn overlies undisturbed bouldery gravel with intermittent thin iron accumulations and in turn overlies compact silty sand with some iron enrichment. The Fe accumulations are probably a result of intermittent lateral water movement through the lower materials. Mining within areas that have been previously disturbed is unlikely to have any detrimental effect on productive capacity and may be beneficial if some fine earth material is replaced at the surface during land restoration.

Takaka soils Takaka soils are soils formed from recently deposited alluvium (pits 2 & 9) and are of somewhat limited extent. At pit 2 multiple flood layering is indicated by several bands of darker coloured buried topsoil and 1.30m of fine earth material overlies

bouldery gravel with Fe accumulations. At pit 9, recent flood alluvium overlies some earlier tailings. Inundation with flood waters while mining in these areas could be avoided by using overburden to construct temporary stop banks.

Ikamatua and Puramahoi soils Ikamatua and Puramahoi soils (pits 3, 4, 6, 10) are soils on older alluvial deposits on more elevated flood free surfaces. These are predominantly well drained soils with an observed thickness of silt loam/sandy loam soil overburden between 0.9 and 1.8m. Because of their deeper and well drained profiles, they are considered to be the soils with the highest productive capacity on the property.

Tukurua and Paton soils Tukurua and Paton soils (pits 5, 7,8) are soils that are moderately well drained to imperfectly drained, their subsoils being effected by the effects of higher groundwater or slow drainage through heavier textured subsurface sediments. At pit 5, groundwater was present at 80cm. The soil at pit 8 is complex, the upper 30cm having formed through the addition of recent sediment from adjacent gully erosion while deeper horizons have some Fe accumulation and have drainage restrictions. No gravel was present within 2.2m in this pit. Removal and replacement of these soils would need to be undertaken in drier conditions to avoid soil compaction.

Onahau soils Onahau soils (pit11) are confined to a restricted area at the west of the property and are occur on an older terrace level. Because of the greater surface age, the soil has developed podzolic features which includes a pale grey subsurface horizon below which is a dark coloured humus/iron pan (not strongly cemented) overlying somewhat weathered partly oxidised gravels. The humus/iron pan is sufficiently developed to restrict the downward movement of water and mining of this area would destroy the iron cemented horizon and result in improved soil drainage. Sluicing would however give rise to higher amounts of fine sediment sowing to the oxidised and partly weathered nature of the subsurface gravels.

Staging of works

Because there are a variety of soils on the property with differing soil/hydrological attributes, it would be appropriate to very selective about where and when differing areas should be worked. Areas with impeded subsurface drainage, for example should only be worked in the driest conditions.

Land Rehabilitation

1 In order to achieve the best possible outcome for productive use of the land

after mining, at any one time, the working area should be kept as small as practically

possible. This is to avoid excessive stockpiling of the topsoil and minimise structural

damage to the soil materials while being stored and during the process of their

successive replacement.

2 The dark brown topsoil (depth approximately 25-30cm) should be separately

removed and stored in piles not more than 1m high followed by the yellowish brown

subsoil (which is of variable thickness) and likewise stored separately.

3 Removal of the topsoil and subsoil should be in strips, by means of a digger

working from the undisturbed land surface to avoid compacting the subsoil material

during its removal.

4 Topsoil and subsoil material should not be removed or replaced at any time

when the soil condition can be described as very moist or wet and is best done under

drier conditions, in order to avoid soil compaction and loss of soil structure. This will

be especially important in the areas that have soil drainage limitations (moderately

well drained to imperfectly drained soils). In areas that have been previously mined

and where the soils are gravelly, the soil moisture condition is off lesser importance.

5 A method will need to be established for replacing the subsurface gravel once

mining has taken place. For the most part, it appears from the pits that the gravel

deposits are relatively thin, so re-spreading should not be difficult. The replaced

gravel may be at a slightly higher finished level owing to a change in the density of

the gravel because of its disturbance. However, since the gravel deposits for the

most part does not appear to be thick, there may not be a significant change in

volume. Fines from the washing can be incorporated back into the gravel but should

be mixed with the gravel and not placed in layers.

6 The surface of the replaced gravel should be smoothed using tracked machinery

and the surface materials (topsoil and subsoil) similarly smoothed with tracked

machinery. The land should be graded in a systematic way to facilitate gentle runoff

and avoid ponding in periods of excessive rainfall. It may be useful to establish

benchmarks, to ensure that a satisfactory land surface configuration is achieved

when the operation is completed.

7 If the area of open ground is kept small, as the operation proceeds a worthwhile

objective would be to replace the removed subsoil and topsoil directly back onto the

restored gravel surface without the need for double handling or extensive stockpiling

of either the topsoil or the subsoil.

8 No foreign soil material should be introduced into the mining area.

9 In areas where the watertable is high (pit site 7) the provision of subsurface

drainage would be beneficial.

10 Restored areas should be sown with appropriate seed and fertiliser with regard

to the expected use of the land following mining.

Figure 1. Geological map of the area

Figure 2 Test pit sites

Figures 3-15 Investigation pit sites and summary of soil materials

888

Pit site 1 Soil Anthropic-well drained Material Tailings/Ikamatua soil/gravel Overburden 2.2m Basement not seen Water not present

Pit site 2 Soil Takaka-well drained Material alluvium/buried soil/gravel Overburden 1.3m Basement granite Water groundwater inflow

Pit site 3 Soil Puramahoi-well drained Material silty alluvium/gravel Overburden 1.1m Basement granite Water groundwater inflow

Pit site 4 Soil Puramahoi-well drained Material silty alluvium/gravel Overburden 0.9m Basement granite Water groundwater inflow

Pit site 5 Soil Tukurua-mod well drained Material silty alluvium/gravel Overburden 0-6m Basement granite Water groundwater inflow

Pit site 6 Soil Ikamatua/well drained Material silty alluvium/gravel Overburden 1.2m Basement granite Water groundwater inflow Basement granite Water groundwater inflow

Pit site 7 Soil Paton-imperfectly drained Material silty alluvium/gravel Overburden 1.2m Basement granite Water groundwater inflow

Pit site 8 Soil Paton-imperfectly drained Material silty alluvium Overburden 2m Basement sandy Water nil

Pit site 9 Soil Takaka/Anthropic-well dr Material silty alluvium/tailings/gravel Overburden 0.4m Basement granite? Water groundwater inflow

Pit site 10 Soil Puramahoi-well drained Material silty alluvium/gravel Overburden 1.8m Basement granite Water small groundwater inflow

Pit site 11 Soil Onahau/imp drained Material silty alluvium with Fe pan Overburden 0.7m Basement granite Water nil

Pit site 12 Soil Ikamatua-well drained Material silty alluvium Overburden 2.2m Basement granite Water nil

Pit site 13 Soil Anthropic-well drained Material stony alluvium/silty sand Overburden 0.6m Basement sandy Water nil

I note Dr Ian Campbell – has detailed 13 test pits and described the soil and geology. Much of the basement seems to be indicative of granite geology – Can Dr Campbell confirm the nature of the granite – was the material encountered the weather overburden or actual insitu hard granite.

The applicant has also attached borelogs from bores near by the TWS and in his response quotes a statement from Dr Campbell which is not in his report.

Could Dr Campbell mark the boundary between the granite basement and tertiary sediment he mentions – considering the borehole location.

Could the applicant also confirm if there would be any risk of lateral movement of groundwater in the overlying sediments heading towards the springs.

Question 6

The use of the term ‘hard pan’ was incorrect but was intended as a description for the hard granite

basement rock that is exposed in places along the Waikoropupu River, and which was also observed

in most of the inspection pits. As noted in the river sections and at the base of the inspection pits,

the granite is fresh and un-weathered. From the size of boulders in the thin (gold bearing) gravel

layer overlying the granite, it can be inferred that the gravels were deposited as part of extensive

flows of Waikoropupu River, probably related to a Late Last Glaciation outwash event, during which

the valley floor granite surface may have been ‘planed’. It is on this granite surface that groundwater

associated with the Waikoropupu River appears to be flowing. Based on the geological map, the

investigation pits and the presence of granite in the river bed, it can be inferred that granite bedrock

occurs throughout the application area at a relatively shallow depth ,around ± 2m.

The boundary of the Onahau granite formation is likely to be the fault line shown on the geological

map. The drill-log for site 6011 shows approximately 30m of sedimentary rock (Motupipi Coal

Measures) overlying Mt Arthur Marble and as this site is some distance east of the application area

and within different geological materials, the data is not likely to be relevant to the present

application. It is likely that the formations encountered in drill log 6011 will extend west to the fault

shown on the geological map.

It is unlikely that groundwater flowing within the application area would move in the direction of

Pupu Spring. The elevation at the Pupu Spring site is shown on the contour map (TDC Top of the

South maps) as 15m whereas the water level in Waikoropupu River immediately to the east is at

13.5m. Further, the 15m level of Waikoropupu River is some distance further up the valley and

approximately 100m SW of the bridge across the river. The drainage system in the lower this part of

Waikoropupu Valley is largely below the level of water in Pupu Spring. Since the water in Pupu

Spring emerges under some pressure, if there was any hydrological connection, backflow from Pupu

Spring into Waikoropupu River would be expected.