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Boliden Summary ReportResources and Reserves | 2018

Kankberg – Åkulla Östra

Prepared by Birger Voigt

Boliden Summary Report, Resources and Reserves 2018, Kankberg – Åkulla Östra| 2

Table of contents1 Summary 3

1.1 Competence 3

2 General introduction 4

2.1 Pan-European Standard for Reporting of Exploration Results,

Mineral Resources and Mineral Reserves – The PERC Reporting

Standard 4

2.2 Definitions 4

3 Kankberg 6

3.1 Major changes 6

3.2 Location 6

3.3 History 7

3.4 Ownership 7

3.5 Permits 7

3.6 Geology 8

3.7 Drilling procedures and data 9

3.8 Exploration activities and infill drilling 11

3.9 Mining methods, mineral processing and infrastructure 12

3.10 Prices, terms and costs 15

3.11 Mineral resources 16

3.12 Mineral reserves 18

3.13 Comparison with previous year 18

3.14 Reconciliation 20

4 References 23

4.1 Internal references 23

Appendix 1 – Brief history


1 SUMMARY

This summary report is issued annually to inform the public (shareholders, potential

investors and their advisers) of the mineral assets in the Kankberg mine held by Boliden

Mineral AB.

The Kankberg mine is located approximately 10 km west of the Boliden Area Operations

process plant in Boliden, and produces gold and tellurium from a deposit hosted by felsic

volcanic and volcaniclastic rock types. The mine has been in production since 2012 and has

since then increased the annual production capacity to ca 450 000 t.

In 2018, the mine produced 456 979 t grading 4.4 g/t Au, 10.7 g/t Ag and 188.3 g/t Te. In

it’s lifetime the mine has produced 2 394 kt grading 3.7 g/t Au, 9.3 g/t Ag and 162.5 g/t Te.

A summary of Mineral Resources and Mineral Reserves are presented in Table 1.

Table 1. Mineral Resources and Mineral Reserves in Kankberg 2018-12-31

Classificationkt Au

(g/t)Ag

(g/t)Te

(g/t)

2018Bi

(g/t)kt Au

(g/t)Ag

(g/t)

2017Te

(g/t)Bi

(g/t)

Mineral Reserves

Proved 2 720 3.8 12 182 94 2 410 3.8 11 181 102

Probable 1 510 3.4 8 153 81 2 130 3.5 10 168 86

Total 4 220 3.7 10 171 89 4 530 3.7 11 175 95

Mineral Resources

Measured 260 4.0 11 155 88 190 3.8 8 130 91

Indicated 600 5.2 7 151 97 310 4.7 8 117 67

Total M&I 860 4.8 8 152 94 500 4.4 8 122 76

Inferred 1 390 5.2 9 209 137 1 360 5.5 8 168 109

1.1 CompetenceTable 2. Contributors and responsible competent persons for this report

Description Contributors Responsible CP

Compilation of this report Birger Voigt Gunnar Agmalm

Geology and exploration Birger Voigt, Susanne Holmen

Resource estimations Lina Åberg

Mineral processing Marie Lundberg

Mining Tina Žižek

Environmental and legal permits

Gunnar Agmalm is Boliden’s Ore reserves and Project Evaluation manager and a member of

AusIMM1 and FAMMP2 Birger Voigt is Mine Geologist at the Kankberg Mine.

1 Australian Institute of Mining and Metallurgy2 Fennoscandian Association for Metals and Minerals Professionals


2 GENERAL INTRODUCTION

This report is issued annually to inform the public (shareholders and potential investors) of

the mineral assets in Kankberg held by Boliden. The report is a summary of internal reports

for Kankberg. Boliden is changing reporting standard from Fennoscandian Review Board

(FRB) to the Pan-European Reserves and Resources Reporting Committee (PERC) “PERC

Reporting Standard 2017”. The PERC Reporting Standard is an international reporting

standard that has been adopted by the mining associations in Sweden (SveMin), Finland

(FinnMin) and Norway (Norsk Bergindustri), to be used for exploration and mining

companies within the Nordic counties.

The previously used FRB standard will no longer be maintained. The PERC standard has

more clearly defined requirements on reporting and on Competent Persons. Boliden is

currently in the process of updating procedures and many of the reports and estimations

summarized here are compiled according to the previous standard (FRB). We consider this

data accurate and reliable. The process of creating PERC compliant estimations, studies and

reports for all Projects and Mines is underway.

2.1 Pan-European Standard for Reporting of Exploration Results, Mineral Resources and Mineral Reserves – The PERC Reporting Standard

PERC is the organisation responsible for setting standards for public reporting of

Exploration Results, Mineral Resources and Mineral Reserves by companies listed on

markets in Europe. PERC is a member of CRIRSCO, the Committee for Mineral Reserves

International Reporting Standards, and the PERC Reporting Standard is fully aligned with

the CRIRSCO Reporting Template.

The PERC standard sets out minimum standards, recommendations and guidelines for

Public Reporting of Exploration Results, Mineral Resources and Mineral Reserves in Europe.

2.2 Definitions

Public Reports on Exploration Results, Mineral Resources and/or Mineral Reserves must

only use terms set out in the PERC standard.

Figure 1. General relationship between Exploration Results, Mineral Resources and Mineral Reserves (PERC 2017)


2.2.1 Mineral Resource

A Mineral Resource is a concentration or occurrence of solid material of economic interest

in or on the Earth’s crust in such form, grade or quality and quantity that there are

reasonable prospects for eventual economic extraction.

2.2.2 Mineral Reserve

A Mineral Reserve is the economically mineable part of a Measured and/or Indicated Mineral

Resource.

It includes diluting materials and allowances for losses, which may occur when the material is

mined or extracted and is defined by studies at Pre-Feasibility or Feasibility level as

appropriate that include application of Modifying Factors. Such studies demonstrate that, at

the time of reporting, extraction could reasonably be justified.


3 KANKBERG

The Kankberg mine is located approximately 10 km west of the Boliden Area Operations

processing plant in Boliden, and produces gold and tellurium from a deposit hosted by felsic

volcanic and volcaniclastic rock types. The mine has been in production since 2012 and has

since then increased the annual production capacity to ca 450 000 t. Mining activity is taking

place in 5 stopes and on average 4 to 5 stopes are in production at any given time and one

primary backfill area.

In 2018, the mine produced 456 979 t grading 4.4 g/t Au, 10.7 g/t Ag and 188.3 g/t Te. In

it’s lifetime the mine has produced 2 394 kt grading 3.7 g/t Au, 9.3 g/t Ag and 162.5 g/t Te.

3.1 Major changes

No major changes or happenings have occurred during the year.

3.1.1 Technical studies

No technical studies have been carried out during 2018. However, steps to investigate and

expand on the currently used density of rock types and spatial density variation has been

initialized.

3.2 Location

The present day Kankberg Au mine is situated 10 km from the processing plant in Boliden

(Figure 2). The Au deposit is located at a depth of 200 – 700 m, below the former Åkulla

Östra open pit mine.

Figure 2. Kankberg is situated 10 km from Boliden. The 1,5 km ramp from the entrance of the old Kankberg mine to Kankberg/Åkulla Östra is drawn in blue


3.3 History

The Kankberg Au deposit was discovered in 1995 and have been drilled periodically from

1995 to 2010. During 1997-1999 a ramp was driven from the old Kankberg mine and in 1999

1 350 t grading 2.4 g/t Au were mined when the ramp passed through the mineralisation. In

2006 11 100 t grading 4.6 g/t Au and 18 g/t Ag were mined for processing tests. During

2007 - 2008 a new drilling programme was completed. At the same time a study for

extraction of tellurides showed good potential for profitability. Further drilling was done in

2009 - 2010, which by May 2010 concluded the geological part of the feasibility study. The

feasibility study was ready in January 2011 and in February 2011 environmental permit was

granted. Development of the mine service facilities and ramps were initiated in May 2011.

Production began in February 2012. See Appendix for a summarised history.

Since beginning of operations until 2018-12-31, 2 395 062 t grading 3.44 g/t Au, 10.5 g/t Ag

and 156.5 g/t Te have been milled.

3.4 Ownership

The deposit is 100% owned by Boliden as well as the ground above it.

3.5 Permits

The Kankberg mine is covered by the mining concessions Östra Åkulla K nr. 1 which is valid

until 2026-02-05 and Östra Åkulla K nr. 2 (black triangle in Figure 3), which is valid until

2034-11-10. A requisite license in accordance with the Environmental Law was issued in

April 2011. Covering the concessions and nearby area Boliden holds an exploration license

Kankberg nr. 1006, which is valid until 2020-11-07.

Figure 3. Exploration licence Kankberg nr. 1006 blue line. Mining concession Åkulla Östra K n. 1 broken line and K nr. 2 black triangle


3.6 Geology3.6.1 Regional

The Kankberg mine lies within the eastern part of the Skellefte field (Figure 4). The Skellefte

field is one of the most important mining regions in Sweden containing numerous

polymetallic sulphide deposits, vein Au deposits and porphyry Cu-Au-Mo deposits. The

majority of known ore deposits in the Skellefte field occur within the upper parts of the

Skellefte group. The Skellefte group is a regionally dominant sequence of volcanic rocks that

were formed during a period of intense, extensional, continental margin arc volcanism about

1.89 Ga ago (Allen et al. 1996).

Figure 4. Geological map of the Skellefte district. Kankberg is situated in the eastern part of the distrcit (modified after Kathol & Weihed, 2005)

3.6.2 Local

The bedrock in the Kankberg area is dominated by volcanic rocks of primarily dacitic and

rhyolitic compositions forming quartz-feldspar porphyritic, rhyolitic and dacitic rock types.

The felsic magmas forming these volcanics intruded as shallow (subvolcanic) dykes and sills

and extruded as lavas at the surface where they mixed with sediments and mass flows derived

from volcanic slopes. The volcanism initiated a convection of solutions through the rocks.

These solutions dissolved and transported minerals and metals to sites of deposition.

After the major volcanic period had ended the area were subsequently deformed and folded.

This resulted in a dominantly vertical trend of the rocks and structures. At a later stage,

brittle deformation took place. Fractures and fissures were intruded by mafic magma forming

basaltic and andesitic dykes, which are common in the Kankberg area.

3.6.3 Property

3.6.4 Mineralization

The Kankberg Au deposit is hosted by primarily quartz-feldspar porphyry, volcaniclastic and

quartz-andalusite rock types. These rocks form a very competent body, which is surrounded

by dacites. In general, a sericite+pyrite±quartz-rich alteration zone is superimposed on the


contact between the host rocks and the surrounding dacites. The host rocks are strongly

altered by silicification, andalusite ± topaz alteration and to a varying degree seritization.

The Au-mineralisation is primarily found within the quartz-andalusite±topaz alteration and

consists of fine-grained native gold, Au-Ag alloys and gold-tellurides. The Au mineralisation

is “divided” into 5 informal ore bodies known as FW1, FW2, M1, M2 and M4 (Figure 5).

Elevated gold grades also occur outside the quartz-andalusite alteration where gold is often

associated with sulphide minerals (pyrite, sphalerite and chalcopyrite).

Figure 5. Schematic illustration of orebodies. FW1 (bright red), FW2 (red), M1 (blue), M2 (grey) and M4 (green). A) plan view, B) S-N profile looking west

3.7 Drilling procedures and data

Diamond core drilling has been carried out for the purpose of exploration and infill drilling.

Exploration drilling is being carried out by the UGN department, who contract’s Protek AB

for the actual core drilling. Infill drilling is being carried out by Boliden personal (G1N), who

operates two in-house drill rigs.

3.7.1 Drilling techniques

Exploration drilling is done using two Diamec U6 drill rigs and wireline 56 systems. This

produce 39 mm drill core.

Infill drilling is done using two drill rigs, Diamec U6 and U4 and wireline 56 systems. During

the autumn 2018 the Diamec U4 was replaced with a Diamec S6.

3.7.2 Downhole surveying

Exploration drilling: Downhole surveying is carried out by Protek personel using an Inertial

Sensing isGyro instrument. About 10 drill holes have been downhole surveyed using a Reflex

Gyro instrument.

Infill drilling: Downhole surveying is carried out by Boliden personel (G1N) using a Reflex

Maxibor II instrument.

In case of an instrument is being sent for service and/or repair, Protek and Boliden personal

loan each other’s instruments.

3.7.3 Sampling

Drill core is logged at Boliden’s core logging facilities in Boliden. Logging is done in

WellCAD software and data is uploaded to an acQuire® database. Sampling adhere to

lithological contacts and generally a sample length of about 2 m is aimed for (>90% of all

samples).

Exploration drill holes are cut with a diamond saw and one half is sent for analysis, the other

half is kept for reference.


Infill drill holes are not split or sawn in half and the whole core, of the part that is sampled,

is sent for analysis. The remaining part of the core is stored for a year, after which it is

discarded.

3.7.4 Density

During the year, beginning in February 2018, Boliden has been requesting measurements of

specific gravity of drill core samples along with chemical assaying. Every fifth sample is

measured using Archimedes principle and all samples are measured using a pycnometer. An

evaluation of the measurements is ongoing.

During the feasibility study for the mine a density of 2.9 t/m3 was determined to be used for

rock classified as ore and a density of 2.8 t/m3 was determined to be used for rock classified

as waste.

3.7.5 Analysis and QAQC

Sample preparation, chemical assaying and measurements of specific gravity is carried out by

ALS Minerals. As part of the QAQC pulp duplicates are sent from ALS to Hazen Reasearch

for Te analysis. Table 3 shows an overview of the methods used.

Table 3. Overview of ALS’s designation of analytical methods. Over-range method applies to samples where assay result reached upper detection limit of primary method

Method Over-range method

Preparation PREP – 22

Assay Au Au-ICP21 Au-GRA21

Assay other ME-M561 Ag-OG62/Ag-GRA21

S-IR08

Te-AA62

(As, Cu, Pb, Zn)-OG62

Specific gravity (core) OA-GRA08

Specific gravity (pulp) OA-GRA08c

Au-ICP21 is a package of fire assay with an ICP-AES analysis. ME-MS61 is a package of a 4-

acid digestion process with an ICP-MS analysis. Periodic table of elements show which

elements (marked in yellow) are assayed for at the Kankberg mine.

H HeLi Be B C N O F NeNa Mg Al Si P S Cl ArK Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br KrRb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I XeCs Ba La* Hf Ta W Re Os Ir Pt Au Hg Tl Pb Bi Po At RnFr Ra Ac¨ Ku Ha

* La Ce Pr Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu

¨ Ac Th Pa U Np Pu Am Cm Bk Cf Es Fm Md No Lr

Quality assessment and quality control is continuously monitored using international

Certified Reference Material (CRM), in-house standards, blanks and umpire lab checks (pulp

duplicates). The aims of the exploration and infill drilling differ slightly and the selection of


the standards/CRM’s used and QAQC procedures therefore differ slightly to address these

aims.

Infill drilling insert QAQC samples according to these guidelines:

Blanks: 1st blank as the 5th - 10th sample, rate 1:50, and after visible gold and/or

particularly strongly mineralised zones

Standards: rate 1:50, grade of standard reflecting suspected grade of mineralised

zone, proportion; 10% low grade (G315-3), 80% medium grade (G913-8) and 10%

high grade (62e/f)

Check assays: rate 1:50, limited to sample series of more than 50 samples, anywhere

in sample series

This result in an average QAQC usage of approximately 5.4% (standards = 2.7%, blanks =

1.7% and check assays = 1.0%).

Table 4. Overview of standards used. During the year, supply of OREAS 62e ran out and Oreas 62f was introduced instead

Type Elements Provider Product Code Gold by Fire Assay (ppm)mean

Gold by Aqua Regia (ppm)mean

Silver (ppm)mean

CRM Au Geostats Pty Ltd

G315-3 1.97 1.97 3.0

CRM Au Geostats Pty Ltd

G913-8 4.87 4.93 8.09

CRM Au OREAS 62e 9.13 9.37 9.86

CRM Au OREAS 62f 9.71 9.59 5.47

In-house

Au Boliden Mineral AB

BS-AU-2 0.50 2.28

Exploration drilling follows the QAQC recommendation given by the Exploration

department. The guidelines themselves are documented in the internal document (Munck, N;

C20556). This result in a QAQC sample frequency of ca. 3% in-house standards, 1.5% CRM,

2% blanks and 0.5% check assays.

3.8 Exploration activities and infill drilling

During the year, a combined total (exploration and infill) of approximately 48 100 m were

drilled. Out of this approximately 7 000 m were exploration drilling on targets outside the

block model extends.

The block model is currently updated twice a year, and between bm_G1N2017_2_2 (as pr.

Sept 20, 2017) and bm_G1N2018_2 (as pr. Sept 20, 2018) 238 new drill holes of 43 933.05 m

have been added to the dataset used for the update.

Exploration drilling was focused on areas above and below the current Life of Mine Plan

(LoMP) whereas infill drilling mainly focused on drilling areas within the LoMP to required

level of confidence for upgrading reserve categorization (Figure 6).


Figure 6. Exploration drilling (red) and infill drilling (green). LoMP presented by the block model in categorization colours. A) looking west, B) oblique looking southwest

3.9 Mining methods, mineral processing and infrastructure3.9.1 Mining methods

The mining method in the Kankberg mine is a cut and fill process. The ore is mined in 6 m

high horizontal stopes (7 m if it is a bottom stope). The stopes are stacked into levels, which

are accessed from the ramp (Figure 7). The mining starts from a bottom undercut and

advances upwards. The mining cycle is comprised of; drilling of the ore, loading of blast

holes, blasting, loading of the ore, cleaning of the exposed rock and reinforcing with

cemented iron rods and shotcrete (Figure 8). Once the stope is mined, media like water,

power supply and ventilation is retreated, as the stope is backfilled with waste material. The

fill material serves both as support for the stope walls and as working platform for the next

stope. The width of stopes varies between 4.5m to 10m. Where the width of the stope

exceeds 10 m, pillars of 6 x 6 m are placed (solid reinforced rock left behind) at 10 m interval

within the stope. On average 4 to 5 different stopes are in production at any given time and

one primary backfill area.

Figure 7. Schematic illustration of mining method


Figure 8. Simplified view of the mining cycle

3.9.2 Mineral processing

Ore is delivered by truck to the industrial area where each truck is weighed on a truck scale

in order to determine the tonnage arriving to the industrial area. Ore arriving at the industrial

area is either taken directly into the processing plant or stored in a stockpile. Separate stock

piles are kept for each of the individual mines in the Boliden area. Ore from the different

mines is processed in campaigns where fresh ore from the mine is combined with ore from

stockpiles. The feed tonnage to the processing plant is determined using a weighing system

with a stationary belt scale. Feed tonnage and weights from the trucks scale are used to

determine current tonnage on the stockpiles.

In the processing plant the ore is ground in two stages (Figure 9). The primary mill is a fully

autogenous mill and the secondary mill is a pebble mill fed with pebbles extracted from the

primary mill. The ground ore is classified using screens and hydrocyclones. A gravimetric

concentrate containing coarse grained gold bearing minerals is produced in the grinding

circuit. The gravimetric concentrate is packed in big bags and delivered by truck to the

Rönnskär smelter.

Flotation is used to produce a precious metals and tellurium concentrate. The concentrate is

accumulated in a leaching tank over a four to five week campaign. After the completion of a

campaign, the concentrate is leached with hot cyanide leaching. The gold containing solution

is then separated from the tellurium-rich leach residue using a belt filter. Electrowinning is

used to precipitate the precious metals in the solution to a sludge that is melted and cast into

doré bullions that are delivered to the smelter.

The tellurium bearing leach residue is leached in a different leaching process in order to

recover the tellurium to a tellurium cement, which is packed in big bags and sold to

customers.

Cyanide leaching at ambient temperature is performed on flotation tailings. Gold and silver is

leached and recovered similarly to gold in the hot leaching process.


Metallurgical accounting where a sum of products calculated using assays from daily

composite samples of main process streams and assays and tonnage for delivered products

together with feed tonnage is used to determine the head grade of the ore.

Figure 9. Simplified overview of the different stages of ore processing

3.9.3 Infrastructure

The infrastructure comprises a main ramp system extending downwards from the old

Kankberg mine to a main level at -400z below surface, where workshop facilities,

underground control room, crew quarters and storage of different kinds are located (Figure

10). From there the ramp leads to a northern ramp and southern ramp system, which both

extends upwards and downwards. The ore bodies are located between the northern and

southern ramp system. The main control room is located above ground.

Ventilation, water management, power supply, communications and control systems are

integrated to create a fully monitored and to a large degree automated control and

management environment of the mine.

Figure 10. Inclined view of the infrastructure, looking west


3.10 Prices, terms and costs

Boliden’s planning prices, which are an expression of the anticipated future average prices

for approximately 10 years, are presented in table 5. Ore value based upon planning prices,

recovery and grade are presented in Table 6.Table 5. Metal prices and currency rates

Metal prices Budget

2019

LTP

2020->

Gold USD/tr.oz 1 227 1 200

SEK/kg 351 381 289 357

Silver USD/tr.oz 14.8 17.0

SEK/kg 4 241 4 099

Tellurium USD/kg 35 30

SEK/kg 312 225

Currency rates Budget

2019

LTP

2020->

USD/SEK 8.90 7.50

EUR/SEK 10.62 8.85

EUR/USD 1.19 1.18

Table 6. Budget and long term ore values for planning. NSR = Net Smelter Return

ORE VALUE (NSR)

Element

BUD LTP

Factor(SEK/t* grade)

Grade Recovery(%)

Value(%)

Factor(SEK/t* grade)

Grade Recovery(%)

Value(%)

Au 306.61 3.92 87 96 247.17 3.29 86 96

Ag 1.62 11.9 34 2 1.38 10.2 34 2

Te 0.18 194.1 56 3 0.13 172.1 56 3

Budget and LTP prices are used for budget and long term planning respectively. The mining

cut-off 525 SEK/t is used to guide mining design and in reserve and resource estimation. A

marginal cut-off of 300 SEK/t is used for material in stopes that is below mining cut-off, but

that needs to be mined anyway. The stope as a whole needs to be at or above 525 SEK/t.

Mining, transportation and processing costs are outlined in Table 7.

Table 7. Costs

Costs (SEK/t)

Mining (except transport of ore in mine) 335

Transportation of ore in mine 40

Transportation of ore 25

Process (without fixed expenditures) 125

Total 525


3.11 Mineral Resources

Using commercially available software packages (Leapfrog, Datamine Studio, Snowden

Supervisor) a 3-dimensionel block model is created into which grade estimations are

interpolated. The project limits and coordinates are in the local Boliden mine system,

“G1NSYSTEMET”. The overall model extends and parameters are outlined in Table 8. The

parent block size of 6*6*6 m is based on drill hole spacing of approximately 10-20 m. For

the purpose of short term planning a sub-blocked model (block sizes down to 1.5 m) based

upon the same estimation parameters is created.

Table 8. Parent block model parameters

Origin Cell size Number

of cells

X 3897 6 110

Y 997 6 90

Z -753 6 110

Statistical and geostatistical studies, sample length analysis, compositing, variogram analyses

define the estimation parameters. Domaining is done on gold grade shells implicitly modelled

in Leapfrog. These grade shells are; 0.5 ppm (waste grade, WG), 1.0 ppm (low grade, LG)

and 2.0 ppm (high grade, HG). The blocks affiliation with grade shells are written into the

block model. The grade estimation is done using ordinary kriging. Block model validation is

done using statistical comparison of composites against block model estimates, validation

plots and visual validation against informing composites. Mineral Resource is classified into

Measured, Indicated and Inferred category. Only small portions of the block model remain

unclassified. The Mineral Resource classification is based upon evaluation of drill hole

density and continuity of mineralization (slope of regression is used as a rough quantifier for

the quality of the block estimate). Generally a sample spacing of at least 60x60 meters is

required for Inferred, 20x20 meters is required for Indicated and 10x10 is required for

Measured.

The block model is covered by what is regarded as mined-out, LoMP (mining design) and

outside LoMP volumes (Figures 11 and 12). Only small isolated parts (not shown in Figures

11 and 12) of the block model are not covered by these volumes.


Figure 11. Oblique view (looking southwest) of the category classification of the block model. Infrastructure and mined-out shown in grey

Figure 12. View of W - E profile (A) and S - N (B) profile of the category classification of the block model

The reported Mineral Resource (Table 9) is the portion of the block model within the outside

LoMP volume, including sill pillers and inferred resources that lie within the LoMP. The

Mineral Resource is reported from the high grade shell only.

The Mineral Resources and Reserves are reported with waste rock dilution and recovery

percentage per category as presented in Table 9.

Table 9. Waste rock and dilution per category

Waste rock

dilution (%)

Recovery

(%)

Category

3.5 100 RESCAT=1 (Proven) Reserve

15 85 RESCAT=2 (Probable) Reserve

3.5 90 RESCAT=3 (Measured) Resource

15 75 RESCAT=4 (Indicated) Resource

20 70 RESCAT=5 (Inferred) Resource


3.12 Mineral reserves

The reported Mineral Reserves (Table 11) are based on the LoMP (mining design). In general

Mineral Resources that are covered by the LoMP are converted into Mineral Reserves (Table

10).

Table 10. Resources conversion

Mineral Resources into Mineral

Reserves conversion

(only within the LoMP)

Resources Reserves

Measured → Proven

Indicated → Probable

Inferred Not converted

Vertical pillars within the LoMP are not included in the Reserves since it is unlikely that they

can be mined.

Sulphur and Copper are not represented in the ore value.

Table 11. Mineral Resources and Mineral Reserves Kankberg 2018-12-31

Classification kt Au

(g/t)

2018Ag

(g/t)Te

(g/t)Bi

(g/t)kt Au

(g/t)

2017Ag

(g/t)Te

(g/t)Bi

(g/t)Mineral Reserves

Proved 2 720 3.8 12 182 94 2 410 3.8 11 181 102

Probable 1 510 3.4 8 153 81 2 130 3.5 10 168 86

Total 4 220 3.7 10 171 89 4 530 3.7 11 175 95

Mineral Resources

Measured 260 4.0 11 155 88 190 3.8 8 130 91

Indicated 600 5.2 7 151 97 310 4.7 8 117 67

Total M&I 860 4.8 8 152 94 500 4.4 8 122 76

Inferred 1 390 5.2 9 209 137 1 360 5.5 8 168 109

3.13 Comparison with previous year

Mineral Reserves have decreased by 311 862 t compared to last year. This is year no new

stopes have been added to the LoMP. The mined out material of 456 903 t has only partially

been compensated by 145 042 t added by changes in mining design brought about by change

in economic parameters (NSR) and results of infill drilling (Table 12).


Table 12. Changes to mineral reserve

Mineral Resources have increased by 385 735 t. This is mainly due to results of exploration

adding 292 483 t and changes of mining design, which added 93 252 t in the inferred

category (Table 13).

Table 13. Changes to mineral resource


3.14 Reconciliation

Reconciliation is done every month (Table 14) and summarized on a yearly basis (Table 15).

Reconciliation at Kankberg is complicated due to overlapping time-shifted timelines of

production, processing and final reporting of result from the smelter.

Table 14. 2018 monthly reconciliation of mine production and mill output

Month

Mined according to grade models Mill output

ton Au Ag Te NSR ton Au Ag Te NSR

t g/t g/t g/t kr/t t g/t g/t g/t kr/t

Jan 42 250 4.3 11.5 230.4 1 406 35 562 3.9 8.7 155.4 1 152

Feb 37 728 6.3 10.7 183.8 2 013 52 762 5.3 11.7 187.9 1 648

Mar 38 921 6.3 9.5 181.2 2 021 27 678 5.1 12.1 153 1 574

Apr 36 550 3.7 9.0 144.6 1 197 30 996 5.8 10.9 130.6 1 914

May 38 663 2.6 8.1 136.7 850 46 860 3.1 13.0 138.3 1 123

June 31 065 3.2 8.6 140.2 955

July 11 768 2.6 27.0 150.7 868

Aug 44 623 2.0 8.7 175.1 615 60 413 2.0 7.0 127.0 645

Sep 30 388 3.9 11.2 213.5 1 174 52 171 3.3 11.0 292.0 1 042

Oct 51 962 3.9 12.1 188.1 1 185 36 180 5.2 13.3 201.8 1 609

Nov 55 758 6.5 14.1 237.6 2 062 24 779 8.2 14.3 295.4 2 722

Dec 49 071 4.5 11.9 205.8 1 424 48 604 4.3 9.7 176.3 1 458

2018 456 979 4.4 10.7 188.3 1 378 427 773 4.2 11.3 182.5 1 364

Graph 1. 2018 monthly reconciliation of mine production and mill output

Table 15. Yearly reconciliation of mine production and mill output

Year

Mined according to grade models Mill output

ton Au Ag Te NSR ton Au Ag Te NSR

t g/t g/t g/t kr/t t g/t g/t g/t kr/t

2012 174 878 2.7 7.7 121.9 1 043 108 949 2.3 4.7 109.0 965

2013 246 542 3.5 7.2 126.3 1 073 324 755 3.2 8.7 133.6 947

2014 324 534 3.5 9.5 149.1 1 044 339 798 3.7 10.1 160.8 1012

2015 371 633 3.5 9.7 183.0 1 057 377 019 3.1 10.2 157.6 937

2016 413 517 3.5 8.8 161.4 1 008 412 345 3.2 11.3 164.3 977

2017 405 995 4.0 9.3 165.6 1 293 404 422 3.5 12.6 147.6 1 106


Graph 2. Yearly reconciliation of mine production and mill output

Kankberg also do reconciliation against Mill Head Grade. Stream sampling from the mill

input (after grinding stage) creates a daily composite sample (Head Grade sample), which is

analysed at the Mill Lab (Fire Assay). Previous study (2017) of daily composite samples has

shown that the analysis of composite samples is a good approximation for the grade of the

ore entering the mill. The reconciliation of Mined vs. Head Grade is presented in Table 16.

Table 16. 2018 monthly reconciliation of mine production and mill head grades

Month

Mined according to grade models Mill head grade

ton Au Ag Te ton Au Ag Te

t g/t g/t g/t t g/t g/t g/t

Jan 42 250 4.3 11.5 230.4 35 758 4.1 11.0 184.0

Feb 37 728 6.3 10.7 183.8 52 762 5.2 12.4 183.0

Mar 38 921 6.3 9.5 181.2 27 038 7.4 13.1 217.0

Apr 36 550 3.7 9.0 144.6 30 996 5.3 9.8 176.9

May 38 663 2.6 8.1 136.7 46 860 2.9 9.6 153.7

June 31 065 3.2 8.6 140.2

July 11 768 2.7 10.8 141.3

Aug 44 623 2.0 8.7 175.1 59 134 2.2 9.0 133.1

Sep 30 388 3.9 11.2 213.5 51 580 3.3 10.9 215.4

Oct 51 962 3.9 12.1 188.1 36 180 5.0 13.8 208.6

Nov 55 758 6.5 14.1 237.6 24 779 10.1 17.6 314.0

Dec 49 071 4.5 11.9 205.8 47 789 6.1 14.3 228.9

2018 456 979 4.4 10.7 188.3 424 643 4.6 11.8 192.4


Graph 3. 2018 monthly reconciliation of mine production and mill head grades

Table 17. Yearly reconciliation of mine production and mill head grade

Year

Mined according to grade models Mill head grade

ton Au Ag Te ton Au Ag Te

t g/t g/t g/t t g/t g/t g/t

2017 405 995 4.0 9.3 165.6 419 673 3.8 11.4 165.8

2018 456 979 4.4 10.7 183.8 424 643 4.6 11.8 192.4

Stock pile at Kankberg held 8 415 t of ore at the beginning of the year and 48 765 t of ore by

the end of the year.


4 REFERENCES

Allen, R.L., Weihed, P., Svensson, S-Å. (1996): Setting of Zn-Cu-Au-Ag massive sulphide

deposits in the evolution and facies architecture of a 1.9 Ga marine volcanic arc, Skellefte

district, Sweden. Economic Geology 91, p.1022-1053.

Kathol, B., Weihed, P (eds.). (2005): Description of regional geological and geophysical maps

of the Skellefte District and surrounding areas, ISBN 91-7158-678-4, SGU: Ba 57

Pan-European Standard for reporting of Exploration results, Mineral Resources and Mineral

Reserves (The PERC Reporting standard 2017.) www.percstandard.eu

4.1 Internal references

For access to internal references contact author or the Head of Department of relevance.

Agmalm, G. (2011): Kankberg, Åkulla Östra mineralization Feasibility Study. Boliden DMS#:

474882.

Bohlin, N.-J. (2010): Mineralogical study of ore samples from Åkulla Östra. Boliden,

TM_REP2009/037.

Baldwin, S. (2018): Kankberg campaign Reconciliation DV_MEMO 2018/01, Boliden DMS

#11900535.

Fahlgren, J. (2015a): A lithogeochemical review of the Kankberg Au-Te deposit, Boliden

Area. Boliden, GP2015-25.

Fahlgren, J. (2015b): GeoGuide_Kankberg_AuTe_Geology_JF_20150415.

Lundberg M. (2018): Mineral processing, Pers. Comm. 2018.

Lundh, J., Holmen-Fröberg, S., Nordfeldt, P., Munck, M., & Wasström, A. (2016):

Kankberg/Åkulla Östra Au-Mineralisation: Exploration Report, 2015 to 1Q2016. Boliden,

GP 2016-20.

Munck, N. (2017): U QA_QC Guideline and work flow (C20556).

Voigt, B. (2017): Kankberg/Östra Åkulla Au-mine, Mineral Reserves and Resources as of

2017-12-31, Boliden Mineral Reserves and Resources Report 2017, DMS# 1160696.

Voigt, B. (2018): Reserves and Resources G1N 2018-12-31, Boliden Mineral Reserves and

Resources Report 2018 (Excel), DMS# 1307888.

Wasström, A. (1997): Au-mineraliseringen i Åkulla Östra. Boliden, GP97003.

Wasström, A., Agmalm, G., & Nilsson, P. (1999): Exploration Report- Status Report 1999

Åkulla Östra Mine Investigation- Geology. Boliden, GP 99 021.


Wasström, A., Agmalm, G., & Sandström, B. (2009): Åkulla Östra Au-mineralisation and

resource estimation 2007-2009. Boliden, GP 2009-47.

Žižek, T. (2018): Mining methods, Pers. Comm. 2018.

Åberg, L. (2018): Mineral Resource estimate for Kankberg, Boliden Ore Reserves Report

2018.


Appendix 1

Brief History

1927 Exploration started in the Åkulla area.

1928 - 1933 Electrical ground measurements. At Åkulla Östra Cu-Au-Zn mineralisation

was found in 4 drill cores.

1938 A drift is made from Åkulla Västra under this mineralisation. A Cu-Au

mineralisation associated with quartz-filled cracks was discovered at a depth

of 130 m.

1939 Åkulla Östra consists of several small sulphide lenses. The drift was filled

with water.

1943 - 1952 Geological exploration and geophysical ground measurements.

1967 - 1969 Drilling and planning for open pit.

1984 Some drill holes drilled in the “Deep-seated sulphide ore” project. No new

mineralisations were found.

1991 A new exploration campaign with geophysical ground measurements and

geological surveying.

1994 Detailed geological outcrop logging and a new drilling campaign. The first

drill hole intersected a new 10 m wide massive pyrite lens at a depth of 260

m in December. The grades were ‘too low’ but the drilling campaign

continued due to geological and geophysical interpretations indicating

mineralisation at a deeper level.

1995 On 1 March a new type of Au mineralisation was found in a strong Si-Al

alteration zone at a depth of 350 m. This alteration zone had mineable

thicknesses with high Au contents.

1996 First metallurgical tests on sample material from drill cores.

1997 - 1998 Åkulla Östra B lens is mined in open pit.

1997 Ramp commenced towards Åkulla Östra Au mineralisation.

1998 - 1999 Exploration within the Åkulla Östra Mine commenced. 20 drill holes.

1998 Processing tests on 1 350 t from the ramp.

2004 - 2006 Åkulla Östra Mine exploration continued. Exploration department drilled

86 drill holes of which 3 were extensions of existing drill holes.

2006 Test mining and a pilot processing test on 11 100 t. Some material from the

1999 ramp was used to clean the line.

2007 A drilling programme of 27 drill holes was initiated, of which one was an

extension of an existing drill hole.

2008 The drilling programme was concluded. Conceptual study on extraction of

tellurides shows good potential for profitability. Analyses campaign on

tellurides.

2009 - 2010 A new ramp is started and a new drilling campaign is completed.

2011 - Infill drilling programme commences.

2012 - Production begins.

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