Chapter 5 | Project Alternatives - Resolute Mining · 2019-11-08 · considerations. Detailed assessment of all major infrastruct. ure options was conducted, including technical

Chapter 9 | Biological Impacts and Management Measures

Chapter 5 | Project Alternatives

Mako Gold Project

Environmental and Social Impact Assessment

FINAL

Chapter 5 | Project Alternatives

ment 5 PROJECT ALTERNATIVES ........................................................................................... 5-3

5.1 Approach to Identification and Assessment of Alternatives .................................................................... 5-3

5.2 Mining Method ......................................................................................................................................................... 5-4

5.3 Waste Rock Dump .................................................................................................................................................... 5-4

5.3.1 WRD Location Screening ........................................................................................................................ 5-5

5.3.2 WRD Design Configuration .................................................................................................................... 5-6

5.4 Tailings Management Facility ............................................................................................................................ 5-10

5.4.1 TMF Location Screening ........................................................................................................................ 5-10

5.5 Process Plant ............................................................................................................................................................ 5-13

5.5.1 Processing Method Alternatives ........................................................................................................ 5-13

5.5.2 Process Plant Location Screening ...................................................................................................... 5-14

5.6 Ore Stockpile ........................................................................................................................................................... 5-16

5.6.1 Ore Stockpile Location Screening...................................................................................................... 5-16

5.7 Water Supply and Management Options ...................................................................................................... 5-18

5.7.1 Water Supply Alternatives .................................................................................................................... 5-18

5.7.2 Water Storage Dam Location Screening ......................................................................................... 5-18

5.8 Access Roads............................................................................................................................................................ 5-21

5.8.1 Access Road Location Screening ........................................................................................................ 5-21

5.8.2 Access Road Design Configuration ................................................................................................... 5-25

5.9 Power Station .......................................................................................................................................................... 5-25

5.9.1 Power Generation Method ................................................................................................................... 5-25

5.9.2 Power Station Location Screening..................................................................................................... 5-25

5.9.3 Power Plant Design Configuration .................................................................................................... 5-26

5.10 Workforce Accommodation Options .............................................................................................................. 5-26

5.10.1 Accommodation Camp Location Screening .................................................................................. 5-26

5.11 Not Proceeding with the Project ...................................................................................................................... 5-27

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5 PROJECT ALTERNATIVES

5.1 Approach to Identification and Assessment of Alternatives

Throughout the design and feasibility study process, a number of different alternatives for mine design and

layout have been considered for the Mako Gold Project. This chapter provides a description and evaluation of

the alternatives considered, and discusses the social and environmental implications of the various options.

Alternative mine designs have been identified and assessed on an iterative basis. The Project has passed

through a number of design phases, including:

Scoping Study / Screening phase;

Pre-feasibility Study (PFS) / Optimisation phase; and

Definitive Feasibility Study (DFS).

Each of these phases has refined the Project design to minimise environmental, social and economic costs as

compared between various proposed alternative Project configurations.

A risk-based approach was used to guide the evaluation of alternatives in relation to each design phase. Those

Project risks and controls identified through the assessment of alternatives have been documented in the Risk Assessment (Volume B).

Key elements and activities of the Project that may potentially result in threats and/or opportunities to the

environment and/or communities include:

Mining activities, including:

o Construction activities and land clearance;

o Excavation of host rock and ore;

Management of waste rock;

Management of tailings;

Ore stockpiling and processing;

Water supply and management;

Access roads and transport;

Power supply; and

Project employment and accommodation.

Potential Project alternatives were first screened to assess whether they have the capacity to meet the technical

requirements of the Project. Options that were technically feasible were then considered in terms of the

following criteria:

Economic feasibility;

Potential environmental impact (including possible ecological impacts and effects on physical /

chemical parameters); and

Potential social costs / benefits (including likely stakeholder perception and potential impacts on public

health and safety).

Alternative options were assessed in terms of methodology, location as well as design configuration (as

appropriate) to ensure optimum design outcomes balancing social, environmental and economic

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considerations. Detailed assessment of all major infrastructure options was conducted, including technical

feasibility and risk analysis.

Key Project design criteria to minimise potential environmental and social impacts (see Chapter 3, Section 3.7.2)

were also considered in the assessment process; in particular, avoiding or minimising potential impacts to:

Niokolo-Koba National Park (PNNK) and the Gambia River;

Habitat of importance to endangered species, and threatened / unique ecosystems (including the

aquatic environment of the Gambia River and its tributaries); and

Local community land and water use.

Taking into account the above, a number of key criteria were adopted for the assessment of alternatives:

Economic Criteria:

o Close proximity to other key infrastructure (to minimise transport distance);

o Minimal footprint (to minimise land take and capital expenditure);

o Rehabilitation and closure;

Environmental Criteria:

o Avoid / minimise adverse impacts to priority habitats (e.g. bowal, gallery forest, Gambia River);

o Avoid / minimise potential impacts to PNNK and the Gambia River;

Social Criteria:

o Avoid / minimise impacts to key land and livelihood resources (i.e. agricultural land, grazing

land, artisanal mining zones, forest resources etc.); and

o Avoid / minimise impacts to community infrastructure (i.e. settlements, roads, archaeological

sites, cultural sites etc.), and health and safety.

A number of potential options for the design and location of Project infrastructure have been considered as

part of the Scoping Study, PFS and DFS process for the Project. Key Project alternatives considered are outlined

in the sections below.

5.2 Mining Method

Open pit or underground ore mining methods can be used to extract ore from a mineral resource. Open pit

mining is usually undertaken where the ore body is broad and/or of a lower grade. Open pit mining is the

primary choice when the ore body is close to the surface. Underground mining is generally favoured for the

mining of narrow and deep high grade ore bodies hosted in certain geological conditions.

The Petowal deposit is proposed to be developed as an open pit mine using conventional methods of drilling,

blasting, loading and hauling using standard industry equipment. Technically, the shape and orientation of the

Petowal deposit on a mountainous ridge lends itself to open pit mining. Open pit mining is also widely

considered to be a safer and more economical extraction method. Based on the ore body geometry, rock

conditions, economics and practicalities of mining, the open pit mining method for the deposit is the only

practicable mining method available at this stage, and no alternative to this approach can be considered viable

for the Project.

5.3 Waste Rock Management

The production of waste rock is a necessary consequence of mining. The rock material that is uneconomic to

process needs to be removed from the pit and deposited into a Waste Rock Dump (WRD). Due to the relatively

large volumes of waste rock this material is deposited as close as feasible to the mine pit, thus minimising

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transport requirements. Small quantities of waste rock may be suitable for use as material for construction for

road gravel and dam structures, as well as for rehabilitation activities at closure.

5.3.1 WRD Location Screening

Two potential WRD location options were identified during feasibility analysis (Figure 5-1). Option 1 is located

adjacent to the Petowal pit, while Option 2 is further to the east/south-east. Both proposed sites are located

about 1.5 km from Tambanoumouya, are south-east of the final Mine Pit, possess the required capacity and are

outside areas of defined priority species habitat or human settlement.

Source: AMEC 2013c.

Figure 5-1 Waste Rock Dump - Siting options

Table 5-1 presents the key siting criteria for each option. Although three archaeological sites fall within Option

1, these are of moderate importance (i.e. have already been identified by archaeologists of having limited

archaeological value) and would be salvaged prior to waste rock dumping. Based on the assessment of

alternatives, Option 1 was selected as the preferred WRD location for further assessment in the DFS.

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Table 5-1 Waste Rock Dump - Key siting criteria matrix

Key Siting Criteria Option 1 Option 2

ECONOMIC CRITERIA

Proximity to Mine Pit 84 m from south-east edge of pit. 1,390 m from south-east edge of pit.

Minimal footprint 133 ha. 122 ha.

Rehabilitation and closure Co-located with other key Project components. Integrated landform at closure.

Isolated landform at mine closure.

ENVIRONMENTAL CRITERIA

Avoid or minimise potential impacts to PNNK and

the Gambia River

1.4 km from nearest PNNK border. 1.5 km from nearest PNNK border.

Ephemeral creek in Petowal-Badalla valley drains to Gambia River. Co-located with other key Project components to contain potential impacts in one catchment.

Ephemeral creek in Niamanoukhou / Kobokou valleys drain to Gambia River.

SOCIAL CRITERIA

Avoids or minimise impacts to land and livelihood

Footprint falls partially on agricultural and grazing land, however, minor impact.

Footprint falls on grazing land only.

Some non-intensive artisanal mining within Badalla Valley.

Intensive and active artisanal mining within the Niamanoukhou / Kobokou valleys.

Avoid or minimise impacts to community assets and

health and safety

3 archaeological sites of moderate importance fall within site.

No archaeological sites.

Location further from community settlements.

Location more proximal to community settlements.

Note: Shaded cells indicate better option(s) for each criteria. All distance and area measurements approximate.

5.3.2 WRD Design Configuration

Six design options, presented in Figure 5-2, were considered for the WRD as part of the PFS (AMEC, 2013d).

These sites were reconfigured to avoid agricultural land and active artisanal sites as well as to reduce

operational costs. The key technical characteristics of the six options are briefly described as follows:

Six design options, presented in Figure 5-2, were considered for the WRD as part of the PFS (AMEC, 2013d). The

key technical characteristics of the six options are briefly described as follows:

V1: Maximises waste storage to the north-west of the Mine Pit with the balance of waste deposited in

the Petowal-Badalla valley to the south-east.

V2: This is a single large waste dump spanning across the full extent of the Petowal-Badalla valley to the

south-east of the Mine Pit.

V3: As in V2, this is a single large waste dump spanning across the full extent of the Petowal-Badalla

valley to the south-east of the Mine Pit, but with the whole dump situated further north and higher up

the valley.

V4: This option abuts the eastern perimeter of the Mine Pit and sits on the western side of the Petowal-

Badalla valley. The overriding benefit of this dump is that it maximises the opportunity, within practical

limits, of employing a cascade style of dump progression which assists in minimising haulage distances.

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V5 and V6: Two additional options which comprise the V4 dump plus a second smaller dump on the

northern side of the Mine Pit. For the purposes of this assessment, these two options have similar

footprints and consequently essentially the same impacts, and have been assessed as one option.

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Source: Toro Gold 2014c

Figure 5-2 Waste Rock Dump - Design configurations

WRD V6

WRD V4

WRD V2 WRD V1

WRD V3

WRD V5

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The same key criteria from the screening analysis were applied to the WRD design, and are presented in Table

5-2 below. Note that all WRD configurations are located adjacent to the Mine Pit. None of the options fall on

priority habitat and no settlements, agricultural land or active artisanal mining sites are present.

Options V3 and V4 were similar and the preferred options based on the analysis. Based on the analysis, the ‘V4’

design was selected as the preferred WRD design.

Table 5-2 Waste Rock Dump - Key design criteria matrix

Key Design Criteria V1 V2 V3 V4 V5/V6

ECONOMIC CRITERIA

Minimal footprint 101.44 ha. 77.94 ha. 70.33 ha. 72.36 ha. ~100 ha. each

Rehabilitation and closure

Two facilities requiring rehabilitation and closure.

Single facility requiring rehabilitation and closure

Single facility requiring rehabilitation and closure

Single facility requiring rehabilitation and closure. Proximity to mine pit improves the opportunity for integrated landform.

Two facilities requiring rehabilitation and closure.


Avoid or minimise potential impacts to

PNNK and the Gambia River

2.8 km from PNNK border.





Northern WRD drains to in Kelendourou Valley in the PNNK. Southern WRD situated in Badalla Valley. Both drain to Gambia River.

Located in ephemeral creek in Badalla Valley which drains to Gambia River. Co-located with other key Project components to contain potential impacts in one catchment.



Northern WRD drains to in Kelendourou Valley in the PNNK. Southern WRD situated in Badalla Valley. Both drain to Gambia River.

SOCIAL CRITERIA

Avoid or minimise potential impacts to

community land and livelihood

1 archaeological site of moderate importance falls within footprint.

3 archaeological sites of moderate importance fall within footprint.

1 archaeological site of moderate importance falls within footprint.



Sited in two small ephemeral Gambia tributaries. Water in Badalla Valley used primarily for artisanal mining during wet season.

Sited in one small ephemeral Gambia tributary. Water in Badalla Valley used primarily for artisanal mining during wet season.



Sited across two small ephemeral Gambia tributaries, water used primarily for artisanal mining during wet seasons.

Note: Shaded cells indicate better option(s) for each criteria. All distance and area measurements approximate.

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5.3.3 Drainage Management Alternatives

The need to line the WRD with a geo-membrane was considered in the design process. Geochemical studies of

waste materials including waste rock were conducted by SRK and Earth Systems as part of the Project's Detailed

Feasibility Study. These studies found there is low to very low geochemical risk associated with the waste rock

(refer to Volume A Chapter 9, Section 9.2). As such, it was found that there is no requirement for installation of

a geo-membrane below the waste rock dump.

The final design configuration of all Project facilities allowed drainage systems to be contained in the Badalla

Catchment. All drainage from the waste rock dump will be contained by the TMF, which will be situated

immediately to the south/south-west of the WRD.

5.4 Tailings Management Facility

5.4.1 TMF Location Screening

Scoping Study and Pre-Feasibility Alternatives Considered

Over 16 alternative sites were identified during the Project scoping and screening phase with the required

capacity for tailings storage over the life of mine (AMEC 2012) (Figure 5-3). This included options in valleys

draining the Petowal Hill; Wayako valley; east of Wayako valley; and north of the NR7 but contained within the

Mako Exploration Permit.

Of these, Sites 1 to 5 were discounted from an environmental perspective as the footprints fell within the PNNK

1km buffer zone, and had capacity constraints in comparison to other options. Sites 9 to 16 were also

discounted due to the following reasons

Greater distance from the Petowal deposit and/or the Process Plant leading to a larger and more

fragmented Project Footprint and higher pumping costs;

Greater impact on settlements and agricultural land in areas north of the RN7; and

Proximity to the PNNK in areas west of Petowal Hill.

Site 6 would require a relatively larger dam than at other sites and was removed from further consideration.

Site 7 was discounted due to capacity constraints and the potential requirement for a saddle dam. The saddle

dam would be located directly upstream of Linguekoto and would probably necessitate resettlement of the

village.

Based on the above, Site 8 was considered the preferred option at the PFS stage of the Project as this TMF

location is relatively close to the mine pit, has sufficient capacity and suitable topographic and geotechnical

characteristics.

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Source: AMEC, 2012. Note that only valleys suitable to contain a TMF are indicated.

Figure 5-3 Tailings Management Facility – Siting options

Option 8 was presented in the Terms of Reference for the ESIA. However, the following impacts and risks were

identified:

Relatively high levels of economic impact due to loss of agro-pastoral land and forestry resources; and

The potential requirement for periodic discharge of tailings supernatant during the operational life of

the facility.

DFS Review and Optimisation

Public consultation was conducted with local villages by rePlan in early 2014 regarding the potential location

of the TMF in the Wayako Valley (rePlan, 2014b). The local villages identified that the impacts associated with

the loss of cultivated land would be significant were the TMF to be sited in the Wayako Valley, particularly due

to the large area potentially affected and the importance of this area for agricultural and forest resource uses.

Further geotechnical investigation, water balance and stability analysis were undertaken by Knight Piesold as

part of the DFS, to assist in refining the preferred location of the TMF. As part of these investigations, an

alternative location was identified in the Badalla Valley close to the Mine Pit (north of the original TMF site 5,

within the exploration permit). This option is secure and stable from an engineering perspective and has key

environmental and social advantages as detailed below:

No discharge from the TMF to receiving waters during operations due to the relatively small watershed

upstream of the embankment;

Containment by the TMF embankment of all potential contaminated run-off and discharge from other

Project facilities, including WRD, ore stockpiles, Mine Pit and the Process Plant area;

Compact Project footprint significantly reducing the requirement for land and habitat loss, degradation

and fragmentation; and

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Relatively minor impacts to local communities resulting from loss of land and natural resources.

The two TMF options considered are shown in Figure 5-4.

Source: Knight Piesold, 2015g.

Figure 5-4 DFS Tailings Management Facility – Siting options

An analysis of alternatives was undertaken of the two DFS options (Table 5-3). Of the two options, Option 2 has

a number of key benefits, including a tighter footprint, narrower embankment, and containment for all water

that enters upstream areas of the Badalla Valley (i.e. the proposed WRD and Mine Pit).

Based on the analysis, DFS TMF Option 2 was evaluated as the preferred TMF option.

Table 5-3 Tailings Management Facility - Key siting criteria matrix during DFS

Key Siting Criteria DFS TMF Option 1 DFS TMF Option 2

ECONOMIC CRITERIA

Proximity to Infrastructure 5 km from proposed Process Plant. 600 m from previously proposed Process Plant. Adjacent to preferred Process Plant.

Minimal footprint 96 ha. 55 ha. Smaller embankment footprint.

Rehabilitation and closure Isolated landform at mine closure Co-located with other key Project components. Integrated landform at closure.

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Key Siting Criteria DFS TMF Option 1 DFS TMF Option 2


Avoid or minimise potential impacts to PNNK and the Gambia River


More extensive footprint - located in separate valley to other infrastructure.

Compact footprint - located in same valley as other infrastructure, reduced disturbance. No discharge during operations.

SOCIAL CRITERIA

Avoid or minimise impact to community land and

livelihood

Moderate – high level impact to agricultural land and livestock grazing resources

Low level impact to fallow agricultural land and livestock grazing resources.

No impact to artisanal mining. Moderate level impact to artisanal mining within Badalla valley.

Avoid or minimise potential impacts to community assets and health and

safety

No archaeological sites. 1 archaeological site of moderate importance falls within.

Large exclusion zone required within the Wayako valley and restrictions on community access..

Co-located with other key Project components within the Badalla valley, minimising the exclusion zone requirements.

Note: Shaded cells indicate the better option(s) for each criteria. All distance and area measurements approximate.

5.5 Process Plant

5.5.1 Processing Method Alternatives

Four comminution circuit configurations were considered during the PFS. A three stage crushing with semi-

autogenous (SAG) mill circuit was selected on technical grounds. No significant environmental or social

differences between the circuit configurations were identified.

Two process routes were considered in the PFS: a Carbon In Leach (CIL) Plant, and a combined Flotation / CIL

Plant (Lycopodium, 2013a). Both process routes utilise similar crushing, milling and gravity concentration

circuits; however, the flowsheet for the downstream circuit differs for the two routes.

The CIL Plant option comprises:

Two main water circuits: process water (cyanide-containing recycled water) and raw water;

One pre-leach thickener prior to CIL;

One tailings pipeline, TMF and decant return pipeline.

The alternative Flotation / CIL plant option adds a further flotation component to the process, with the aim of

increasing gold recovery prior to cyanide application.

A cyanide detoxification circuit to reduce cyanide concentration in the TMF to below international standards

was identified as a requirement for both process routes.

Flotation did not lead to a significant increase in gold recovery at Mako and was quickly discounted as a viable

option for the Project.

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5.5.2 Cyanide Destruction Alternatives

Several alternatives for cyanide detoxification / destruction where considered in the design process. These

included:

Alkaline Chlorination;

Hydrogen Peroxide;

SO2/Air;

Ferrous Sulphate Complexation;

Caro’s Acid; and

Ozonation.

Project testwork confirmed that an INCO-based SO2 / air cyanide destruction circuit would be effective in

reducing the tailings cyanide concentration to meet the International Cyanide Management Code (ICMC)

requirement of <50mg/L WAD cyanide, and this method was therefore selected as the preferred alternative for

the Project. The SO2 / air method of cyanide detoxification / destruction is a standard process used by industry.

5.5.3 Process Plant Location

It is preferable that the Process Plant is located in close proximity to the TMF to reduce pumping requirements

and the length of infrastructure corridors.


Four process plant locations were examined by Lycopodium in October 2013 for the PFS (Figure 5-5). The plant

sites were evaluated based on their distance to the TMF and pit, as well as environmental and social

considerations. Of these, Option A was identified as preferable due to being the best outcome when weighed

against site terrain, haul distance, piping lengths, earthworks and land take requirements (Lycopodium, 2013b).

Source: Lycopodium, 2014

Figure 5-5 Project Scoping / PFS Process Plant - Siting options

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Subsequent to the decision to move the TMF from Wayako Valley to the Badalla Valley, two potential Process

Plant site options were proposed (Figure 5-6). These did not fall on settlement areas, artisanal mining sites or

cultivated agricultural land, although the footprints did fall on land that can be used for grazing. The sites were

located on elevated ground on the border of two catchments.

Source: Knight Piesold, 2014a; Knight Peisold, 2015g.

Figure 5-6 DFS Process Plant - Siting options

The main economic criteria is that the Process Plant is as close in distance and height to the Mine Pit (to reduce

ore transport costs to the plant), the TMF (to reduce slurry transport distance to the TMF) and the Water Storage

Dam (to reduce water pumping).

From an environmental and social perspective, Option B is closest to both the Gambia River and the PNNK, and

falls on both priority species habitat (bowal) and archaeological sites. It is also closer to Tambanoumouya

village, with potential construction dust impacts as well as noise impacts during all Project phases. However, it

is at a site that requires less earthworks and enables a more compact footprint. It is also further from high value

habitat to the north and east of the mine pit. Placing the process plant as per Option B also allows the Ore

Stockpile to be co-located with the WRD.

On the balance of the studies, Option B resulted in a considerable reduction in initial and operating costs and

was selected as the preferred alternative. It was considered that Option B had a lower overall environmental

impact and risk.

Table 5-4 Process Plant - Key siting criteria matrix during DFS

Key Siting Criteria Option A Option B

ECONOMIC CRITERIA

Proximity to Infrastructure

(Mine Pit, TMF, Water Storage Dam)

680 m from preferred TMF. Adjacent to preferred TMF.

130 m higher elevation from Mine Pit. 30 m lower elevation from Mine Pit.

Minimal footprint Overall footprint of 5 ha. Overall footprint of 9.5 ha.

Process Plant DFS Option A Process Plant DFS Option B

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Key Siting Criteria Option A Option B


Avoids key ecological habitat Does not fall on priority species habitat. Falls entirely on priority species habitat (bowal).



SOCIAL CRITERIA

Avoid or minimise potential impacts to community land and water

use

No archaeological sites. 2 archaeological sites (one high and one moderate importance) fall within.

5.6 Ore Stockpile

5.6.1 Ore Stockpile Location Screening

The mining of ore will be conducted at a rate in excess of processing. This will necessitate the development of

an Ore Stockpile.


The PFS identified one location for the Ore Stockpile, immediately adjacent to the north-east of the Mine Pit

(Figure 5-8) and falling within the Kelendourou Valley catchment, which drains into the PNNK prior to the

Gambia River. This site was chosen due to its proximity to the pit and process plant. No other options were

proposed until the DFS so that the mining schedule and therefore volume of ore to stockpile could be better

estimated.


During the DFS review, the size of the Ore Stockpile was significantly reduced due to the refinement of the

mining scheduling. Three main Ore Stockpile locations were assessed (Figure 5-7):

Option 1, draining into the Kelendourou and Badalla Valleys;

Option 2, draining into the Badalla and Wayako Valleys; and

Option 3, draining into the Badalla Valley within the area of the WRD (to be laid upon a bed of waste

rock).

All of the options were located at sites where there was no priority species habitat, artisanal mining or

cultivated land, although the land is suitable for grazing.

Based on the assessment of alternatives shown in Table 5-5, Option 3 within the WRD in the Badalla Valley was

chosen based on proximity to the Mine Pit and Process Plant, as well as environmental and social

considerations. As with the consideration of alternatives regarding the TMF, placing the Ore Stockpile within

the Badalla Valley results in a tight footprint with most infrastructure within one catchment, and avoids impacts

on the adjacent Wayako Valley and creeks that drain back into the PNNK.

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Sources: Option A - Toro Gold 2014c. Option B - Knight Piesold, 2015g. Option C – Coffey, 2015 (Harry Warries, Pers. comm., 22 May 2015).

Figure 5-7 PFS and DFS Ore Stockpile - Siting options

Table 5-5 Ore Stockpile - Key design criteria matrix during DFS

Key Design Criteria Option 1 Option 2 Option 3

ECONOMIC CRITERIA

Proximity to Infrastructure Adjacent to Mine Pit. 733m from the Mine Pit. Adjacent to Mine Pit.

Minimal footprint 6 ha. 17 ha. 6 ha, located within the WRD footprint.



2.6 km from nearest PNNK border.

3.5 km from nearest PNNK border.

2 km from nearest PNNK border.

Straddles two catchments, one which drains via PNNK to Gambia River.

Located in same valley (Badalla Valley) as other infrastructure.

Located on western extent of Wayako Valley.

SOCIAL CRITERIA

Ore Stockpile Option 1 Ore Stockpile Option 2

Ore Stockpile Option 3

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Key Design Criteria Option 1 Option 2 Option 3

Avoid or minimise potential impacts to community land and water use

2 archaeological sites (one high and one moderate importance) fall within.

No archaeological sites. No archaeological sites.

5.7 Water Supply and Management Options

5.7.1 Water Supply Alternatives

The Project requires a secure water supply to ensure continuous operation of the Process Plant and for other

mining demands.

The Company has considered the following water supply options:

Retention of surface water runoff within a surface Water Storage Dam (WSD).

Abstraction of water from the Gambia River.

Abstraction of groundwater from aquifer storage.

Surface water availability in the proposed Mining Concession is characterised by marked seasonal variation,

with little to no surface water flow during the dry season. Consequently, retention of water within a WSD is

required to ensure a continuous water supply for mining and plant operations.

Hydrogeological information indicated that there was insufficient groundwater in the area to support Project

requirements. Groundwater sources may, however, be sufficient for some applications e.g. drinking water at the

Accommodation Camp. Due to the extended periods with no inflows and the high evaporation rates identified

in the local area and relatively small local catchments, it was determined that retention of wet season runoff

would be insufficient to meet Project demand. The potential for surface water abstraction from the Gambia

River to supplement the retention of wet season runoff was therefore considered. In order to avoid any impacts

on hydrology and biodiversity, the pumping regime will only allow water abstraction from the Gambia River

during the wet season. Later hydrological studies have shown that the total annual supply of mine water

proposed during a dry year represents 0.04% of the Gambia River annual flow and 0.03% of the annual Gambia

River flow during the median year (see Chapter 9, Section 9.4).

Based on the above, the preferred water supply option is use of a WSD to capture water during the wet season

to provide operational security through the dry season, supplemented by Gambia River abstraction during the

wet season only.

5.7.2 Water Storage Dam Location Screening


Two WSD options were considered during the Scoping Study and PFS (Figure 5-8):

WSD Option 1: located in the Kobokou Valley and has a water abstraction point on the Gambia River

approximately 750 m to the south, and

WSD Option 2: situated in a western tributary of the Wayako Valley / Bowoyoto Creek and has a water

abstraction point on the Gambia River approximately 1.8 km to the south-east.

A third option (WSD Option 3 on Figure 5-9) was located slightly further downstream along Bowoyoto Creek

towards the settlement of Linguekoto. However, this was considered too large and expected to have potential

sedimentation issues, and was consequently discounted. A fourth WSD option located downstream of the

WRD was also considered during the PFS, in order to capture seepage and run-off from the WRD and to allow

for the capture and re-use of water during operations. This option was disregarded once the Project DFS altered

the TMF location to be downstream of the WRD, thus replacing the proposed role of the WSD.

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Table 5-6 presents the key siting criteria for the two options. Both sites avoided priority species habitats,

settlements and cultivated land, although did fall on potential grazing land.

Source: Toro Gold, 2014c.

Figure 5-8 Scoping / PFS Water Storage Dam – Siting options

The main economic criteria is minimising the pumping distance from the Gambia River to the WSD. From this

perspective, both options were fairly similar. Of the two options, Option 1 was considered more appropriate

from a social perspective as it was not located directly upstream from Linguekoto and therefore avoided the

risk of dam break on the village.

Based on the assessment of options, Option 1 was selected as the preferred WSD location for further refining

in the DFS.


The location of the WSD was subject to slight revision during the DFS. This increased the WSD volume based

on DFS water demand and thereby the footprint to 13.6 ha. The angle of the dam wall was changed, and the

Potential Zone of WSD Option 3

WSD Option 1

WSD Option 2

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wall was moved approximately 130 m downstream (Figure 5-9). The location of the water abstraction point did

not change.

Table 5-6 Water Storage Dam - Key siting criteria matrix during Project Scoping / PFS

Key Siting Criteria WSD Option 1 WSD Option 2

ECONOMIC CRITERIA

Proximity to Process Plant 1.8 km from Process Plant. 1.5 km from Process Plant

Minimal footprint 7.7 ha 8.8 ha



2 km from nearest PNNK border. 2.9 km from nearest PNNK border.

Ephemeral creek drains via Kobokou Valley to Gambia River.

Ephemeral creek drains via Wayako Valley to Gambia River.

SOCIAL CRITERIA

Avoids key land and livelihood resources

Some non-intensive artisanal mining within Kobokou Valley and along Gambia River.

No artisanal mining.

Avoid or minimise potential impacts to community assets and health and

safetye

No settlements impacted or directly downstream.

Linguekoto directly downstream.

Sited in one small ephemeral Gambia tributary, water used primarily for artisanal mining during wet season.

Sited in one small ephemeral Gambia tributary, water used primarily for cultivation during wet season.

Note: Green shaded cells indicate most appropriate option(s) for each criteria. All distance and area measurements approximate.

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Source: Knight Piesold, 2014a

Figure 5-9 Preferred DFS Water Storage Dam configuration

5.8 Access Roads

5.8.1 Access Road Location Screening

Given the numerous iterations undertaken to refine the Project footprint, Project Access Roads were

continually revised during the PFS and DFS. Consequently, the following section summarises the key decisions

taken during the Scoping Study and PFS regarding the entry point for the Access Road, and an assessment of

alternatives is provided in the DFS section.


Two alignments were initially considered for the primary access road:

Option 1 - Access road via Mako-Tambanoumouya road with entry via Mako village, and

Option 2 - Access road via Wayako Valley with entry to west of Niemenike.

A decision was made early during Project Scoping to avoid using the existing Mako-Tambanoumouya road as

the main access route between RN7 and the PDA. The Mako-Tambanoumouya road runs between the villages

of Mako and Tambanoumouya via Linguekoto, and was used during the exploration phase for access to the site

and existing exploration camp. In so doing, the Project would avoid traffic-related impacts and safety issues to

the roadside communities of Mako, Linguekoto and Tambanoumouya.

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Consequently, Option 2 was selected as the preferred Main Access Road alignment arising from the PFS (Figure

5-11). This road starts at the national highway (RN7) approximately 2 km west of Negue Bako village (Niemenike

cluster), and passes southwest through the Wayako Valley.


Options to access the Project Development Area via the western foothills of the Wayako Valley were also

discounted due to the presence of groundwater springs which were subsequently identified as an important

dry season drinking water source for wildlife, including endangered species. During the camera trapping work

conducted for the Terrestrial Ecology and Biodiversity Study, fauna were most frequently photographed at

or near a spring site located along the ephemeral stream directly south (downstream) of the initial alignment

of the proposed Main Access Road (see zone in green indicated on Figure 5-10; further information provided

in ESIA Chapter 6). Several species were photographed drinking from, or sitting beside, the pooled water of

these springs, including the priority species chimpanzees and leopard. The identified spring sites appear to

provide a perennial water source, which is important given that there is usually little flow in the creeks except

when there is high rainfall.

Positioning a road upstream of these water points would create a barrier for wildlife access, likely impact on the

water quality and the species relying on it during the dry season. As a result, the alignment of the Main Access

Road was retained within the Wayako Valley until its junction with the existing Mako – Tambanoumouya Road.

Two alignments avoiding the area of the spring and other watering points potentially used by fauna, and taking

into account the preferred location for the TMF, were considered and are shown in Figure 5-11.

Option 1 - The road runs south along the western edge of the Wayako Valley and forks north of the WSD,

with access roads joining the main access route to the Process Plant to the west and the WSD to the

south. Note the connection from the WSD to the water abstraction point is a pipeline only and does not

have an associated access road.

Option 2 - The road runs south along the western edge of the Wayako Valley and joins the Mako-

Tambanoumouya road to the west of Linguekoto; it then runs parallel to the Mako-Tambanoumouya

road and then heads north-west towards the PDA, in part following an existing exploration track.

Table 5-7 presents the assessment of alternatives. Both options avoid passing through settlements, but Option

2 passes closest to the PNNK and also runs parallel to a 1.3 km section of the existing Mako-Tambanoumouya

road. Both alignments have sections to the south that cross ephemeral streams with catchments that pass

through the PNNK buffer zone, although in zones that are already heavily utilised by communities. Neither

option falls on archaeological or cultural sites.

Although Option 1 has fewer associated environmental and social constraints, it does pass close to the

identified springs and it also possesses considerably higher capital expenditure. Based on this, Option 2 was

selected as the preferred alignment.

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Source: AMEC, 2014

Figure 5-10 Scoping / PFS Access Roads – Siting options

Area where perennial springs are

present

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Source: Option 1 – Knight Piesold, 2015g. Option 2 – Toro Gold, 2015g.

Figure 5-11 DFS Access Roads - Design configurations

Access Road Option 1 Access Road Option 2

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Table 5-7 Access Roads - Key siting criteria matrix during DFS

Key Siting Criteria Option 1 Option 2

ECONOMIC CRITERIA

Minimal footprint Higher cut and fill requirement to allow routes to climb hills at reasonable angle.

Requires less cut and fill as land is flatter.

Overall alignment of 15 km. Overall alignment of 12.4 km.


Avoids key ecological habitat Crosses 150 m of priority habitat (bowal).

Crosses 700m of priority habitat (bowal).


Relatively distant to PNNK border. Passes in close proximity to PNNK border, especially to the south of the Process Plant and TMF.

SOCIAL CRITERIA

Avoids key socio-economic resources Passes through 2.1 km of agricultural land, as well as grazing land.

Passes through 2.7 km of agricultural land, as well as grazing land.

Avoid or minimise potential impacts to community land and water use

Does not involve the use of existing community routes.

Does not involve the use of existing routes, although will run parallel to a portion of the Mako-Tambanoumouya road.

Crosses numerous ephemeral streams used for agriculture and artisanal mining.

Crosses numerous ephemeral streams used for agriculture and artisanal mining.

5.8.2 Access Road Design Configuration

The main design alternatives for road construction are the use of surfaced (bitumen) or un-surfaced (i.e. laterite)

roads. The key issue associated with un-surfaced roads is dust generation; this will require regular watering to

ensure that dust is adequately controlled. In contrast, surfaced roads entail higher capital costs and require

more work to repair (i.e. in comparison to repairing laterite roads after the wet season). The preferred option is

a combination of the two: using un-surfaced laterite for flat sections and surfaced road in steep sections where

necessary.

5.9 Power Station

5.9.1 Power Generation Method

There is no opportunity for grid connected power for the Mako Gold Project, and therefore a stand-alone Power

Station will be required. Consideration was given to renewable energy sources. Consideration was also given

to establishment of a hybrid power supply facility comprising both diesel fired engines and solar generation.

Under this option solar energy would reduce diesel consumption over the life of mine and reduce CO2

emissions (greenhouse gas). However, this option was discounted due to the relatively high capital cost and

extended payback period, notwithstanding the need to identify sufficient land area for the solar field. A Power

Station using fuel-driven generator units was therefore considered the preferred option for the Project.

5.9.2 Power Station Location Screening

The key technical consideration for siting of the Power Station is proximity to the Process Plant. Close proximity

is advantageous as it reduces the requirement for power transmission (and its associated power losses) by

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being as close as practical to the largest power load, as the Process Plant is the main consumer of energy for

the Project.

During the Scoping, PFS and DFS, the location of the Power Station was adjacent to the Process Plant. Section

5.5.2 provides further information on the potential siting options related to the Process Plant.

5.9.3 Power Plant Design Configuration

The Project Scoping Study indicated that the generator units for the Power Plant could be run off Heavy Fuel

Oil (HFO), Light Fuel Oil (LFO) or diesel. Due to its density, HFO requires specialist facilities for storage and

transport compared to LFO and diesel. However, HFO is significantly cheaper than LFO or diesel, and is utilised

for power generation at other mines such as Teranga’s Sabodala mine.

From an economic perspective, HFO was excluded as an option by equipment providers as being unsuitable

for the small load (76 GW/a) and relatively short project life (around 8 years is the crossover point for diesel

equipment based on capital and payback periods) (Toro Gold, 2015g). Given that the environmental and social

implications of transporting and storing HFO and diesel are essentially the same, diesel was therefore selected

as the preferred fuel type for power generation for the Project. Air emissions from diesel power generation are

less than when HFO is used as a fuel source.

5.10 Workforce Accommodation Options

5.10.1 Accommodation Camp Location Screening


Based on the expected number of workers for both construction and operations, a new Accommodation Camp

is considered necessary to provide accommodation for expatriate and senior Senegalese employees. The

existing Project Exploration Camp is located on the Mako-Tambanoumouya road. To access this site, vehicles

would have to pass through Mako and use a road commonly used by residents from the villages of Mako,

Linguekoto and Tambanoumouya (refer Section 5.8). Due to the potential health and safety issues associated

with the long-term and intensive use of this camp location, alternative Accommodation Camp locations for the

Project were required.


Further iterations of the Project design during DFS resulted in the construction and operation camps being

combined into one site.

Based on the DFS location of the TMF and Process Plant, two new alternative camp sites were considered in the

DFS (Figure 5-12). Both sites are located along the Main Access Road for the Project.

The preferred site was located further south as it minimised the risk of disturbance to groundwater springs that

were identified as being important for local wildlife (refer to Section 5.8). Locating the camp at the northern

location would increase human presence in the area as well as potential noise generation, light disturbance

and other anthropogenic impacts (see ‘Alternate Camp Site’ in Figure 5-12).

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Source: Knight Piesold, 2014g

Figure 5-12 DFS Accommodation Camp - Siting options

5.11 Not Proceeding with the Project

The direct consequences for Senegal of not proceeding with the Project can be summarised as follows:

The Petowal Deposit would remain undeveloped, and the Project would not contribute to gold exports

from Senegal - consequently, the Sabodala Gold Mine would remain the only large-scale gold mine

currently in operation in Senegal;

Investment, taxation and royalty benefits from the Mako Gold Project to the Government of Senegal

would not be received;

There would be no opportunity for employment, training or skills development associated with the

Project, with hundreds of Senegal nationals expected to be employed during construction and

operation. Any current Company employees associated with exploration activities in the Exploration

Permit area would not find ongoing employment with the Company;

Improved infrastructure associated with the Project and its benefits to local communities would not be

realised;

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Local procurement and strengthening of supply chains would not be realised;

Any land, water and air residual impacts (after mitigation and management) associated with the

development of the mine will not occur;

Potential socio-economic and health impacts and risks of the Project would not occur;

Potential impacts to the terrestrial and aquatic biological environment from the Project would be

avoided, and any environmental and sustainability initiatives (e.g. biodiversity offsets and monitoring)

adopted by the Project would not occur;

The Project would not add to the cumulative impacts of other development in the region – including

both potential positive and negative impacts; and

Villages surrounding the Project Development Area and more broadly the Commune of Tomboronkoto,

would not benefit from community development financed through the Company’s environment and

social investment programme.

At the national level, not proceeding with the Project would result in the loss of indirect benefits, including a

loss of potential flow-on benefits and external effects for the GRS. Flow-on benefits associated with the Project

include local business development and general increased consumption in the local communities resulting

from the injection of cash into the local economy. Such flow-on benefits will generate additional revenue to

the GRS through taxes paid by businesses and on goods purchased in the new cash economy. External effects

which would not occur include skills development, capacity building of GRS representatives and technology

transfer which could have benefited Senegal as a whole.

If the Project were not to proceed, indirect impacts associated with the Project on water supply and quality

(such as in downstream areas) or increased pressure on local agricultural land, forest and water resources due

to in-migration associated with the Project would not occur. However, indirect socioeconomic benefits would

also not be experienced at both the local and national levels. These are primarily associated with socio-

economic opportunities that would have flowed on from the development of the Project such as the

development of businesses and employment opportunities to support the Project. The experience of other

mining projects in Senegal such as Teranga’s nearby Sabodala Gold Mine indicate that these opportunities can

be significant. Potential direct and indirect impacts of not proceeding with the Project are further detailed in

Chapters 9 to 11, while potential socio-economic benefits of the Project are summarised in Chapter 2.

Documents

Chapter 5 | Project Alternatives - Resolute Mining · 2019-11-08 · considerations. Detailed assessment of all major infrastruct. ure options was conducted, including technical