Benkala Mine Visit Report

7/29/2019 Benkala Mine Visit Report

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BBEENNKKAALLAA MMIINNEE VVIISSIITT RREEPPOORRTT

11:: IINNTTRROODDUUCCTTIIOONN::

A visit to the Benkala mine, owned and operated by Kazcopper, was made on 21st

August 2012.This report summarises the findings and observations.

In summary, the mine and processing facility was designed as fit for purpose.

To improve cash flow and recoup initial capital investment early, it was circumspect to

commence mining on the richest part (+1.2% Cu) of the orebody (Figure 1), twice the designed

grade of the plant at steady state.

FFiigguurree 11::

VViieeww ooff

BBeennkkaallaa

ooppeenn ppiitt,,

tthhee rriicchheesstt

ppaarrtt oofftthhee

oorree ddeeppoossiitt

The total labour force at the mine is around 250. Managerial staff has been stable but turnover

at the lower levels has been as high as 40%. This is to be expected with a new facility, operating

in a remote part of the country. This evolutionary process will build a stronger team, with acommon sense of dedication and purpose.

Availability of competent rock for overliner material is a problem at the site; as a result, this

material is quarried and transported from 60 kms away.

Experiences learnt from this project can be used on future projects for a smoother and trouble

free start up.

The prudent philosophy adopted was to curtail cost at the front end of the plant but install the

best equipment at the money making back end.


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22:: GGEENNEERRAALL OOBBSSEERRVVAATTIIOONNSS::

2.1: ACID OFFLOADING

This is carried out in open air, Figure 2. The major exposure of the operator to harsh weatherwill be in the opening and closing of the offloading hatch of the acid tanker.

FFiigguurree 22:: OOppeenn aaiirr aacciidd

ooffffllooaaddiinngg ssttaattiioonn

A simple, but effective, priming system enables remote operation of the offloading pumping

system, Figure 3.

FFiigguurree 33:: AAcciidd ooffffllooaaddiinngg

ppuummppss pprriimmiinngg ssyysstteemm.. AA

ddiiffffeerreenntt aanndd mmoorree

ssuuiittaabbllee fflloooorriinngg mmaatteerriiaall

wwiillll bbee rreeqquuiirreedd


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2.2: FLOORING

Locally made hard wearing tiles have been used at a fraction of the cost of ceramic tiling.

However, because of the high expansion coefficient of this material, it is only suitable for indoor

application, Figure 4. An alternative will be needed for outdoor application.

FFiigguurree 44:: FFlloooorr ttiilliinngg uusseedd

iinn tthhee ppllaanntt,, nnoott ssuuiittaabbllee

ffoorr oouuttddoooorr aapppplliiccaattiioonn

dduuee ttoo iittss hhiigghh eexxppaannssiioonn

ccooeeffffiicciieenntt

2.3: STRONG ACID STORAGE

The storage of concentrated sulphuric acid complies with the Kazakhstan regulations of the

tanks being suspended 1.7 metres above ground level, for mandatory leaks inspection, Figure 5.

FFiigguurree 55::

SSuuppppoorrtt ffoorr

ccoonncceennttrraatteedd

aacciidd ttaannkk,,

aalllloowwiinngg 11..77

mmeettrreess ooff

hheeaadd

cclleeaarraannccee ffoorr

lleeaakkss

iinnssppeeccttiioonn


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2.5: PLANT UPPER FLOORING and STAIRS

Reinforced plastic grating was imported from China and used exclusively flooring and stairways

Figures 6, and 7. The overall finish is neat and even.

FFiigguurree 66::

RReeiinnffoorrcceedd

ppllaassttiicc ggrraattiinngg

uusseedd ffoorr

fflloooorriinngg

FFiigguurree 77::

RReeiinnffoorrcceedd

ppllaassttiicc ggrraattiinngg

uusseedd ffoorr ssttaaiirrss


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2.6: USE OF STAINLESS STEEL FOR TANKS

The use of stainless steel for the construction of some tanks proved to be a wrong choice. Leaks

have developed in a very short time, Figure 8.

FFiigguurree 88::

AA LLeeaakk iinn aa ssttaaiinnlleessss sstteeeell ttaannkk

A better choice is Fibre Reinforced Plastic (FRP). Repairing a leak on an FRP tank is an easy job

whereas that for a stainless steel tank is a protracted procedure, and success is not guaranteed.

2.7: PICKET FENCE CONSTRUCTION

The picket fence construction is the simplest the author has seen in his career. It entailed the

splitting of an HDPE pipe longitudinally and using it, Figure 9.

FFiigguurree 99:: PPiicckkeett

ffeennccee

ccoonnssttrruucctteedd

ffrroomm HHDDPPEE ppiippee


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2.8: CHOICE OF RECTIFORMER

The choice of rectiformer was also well planned. By buying from Rapid of the USA, Figure 10, it

was 40% cheaper than buying from one of the larger suppliers such as ABB. However, there

were disadvantages as Rapid did not provide a packaging and logistical service. Additional, but

marginal expenses were incurred for those services.

FFiigguurree 1100:: RRaappiidd

rreeccttiiffoorrmmeerr,, 4400%% cchheeaappeerr

tthhaann tthhee nneexxtt nneeaarreesstt

ccoommppeettiittoorr

2.9: THE PRESENCE OF ACID MIST IN THE ELECTROWINNING TANKHOUSE

Acid mist is evident in the electrowinning tankhouse, but the situation on the day of the visit

was not unbearable, Figure 11.

FFiigguurree 1111:: AAcciidd mmiisstt

iinn tthhee eelleeccttrroollyyttiiccttaannkkhhoouussee


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Measures are in place to attenuate the acid mist generation problem, namely:

The use of plastic balls to curtail emission of mist, and The use of a flexible, and impervious, plastic mat above the cells to contain the mist

The author feels that both of these measures will be more effective than the ubiquitous

fume hood/extractor fan/scrubber combination, and significantly cheaper also.

2.10: CATHODE QUALITY

Cathode quality is very good. There was no sign of nodulisation, Figure 12. It is early days yet.

Nodules form with the build up of impurities within the process.

FFiigguurree 1122:: NNoodduullee--ffrreeee

ccooppppeerr ccaatthhooddeess aatt

BBeennkkaallaa

2.11: VALVES WITHIN THE PLANT

Plastic valves, imported from Italy, are used exclusively within the plant, Figures 13 and 14.

Their feel and appearance reflect a quality product.


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FFiigguurree 1133:: SSmmaalllleerr

ddiiaammeetteerr IIttaalliiaann mmaaddee

ppllaassttiicc vvaallvvee,, uusseedd

wwiitthhiinn tthhee pprroocceessss

bbuuiillddiinnggss

FFiigguurree 1144:: LLaarrggeerr ddiiaammeetteerr IIttaalliiaann mmaaddee ppllaassttiicc vvaallvvee


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2.12: PREGNANT LEACH SOLUTION (PLS) FEED PUMPS

Centrifugal pumps with a dedicated priming system have been employed for this purpose,

Figure 15. These pumps are significantly cheaper than the turbine pumps proposed for Aktogay.

They are capable of sucking from a fairly deep PLS pond, Figure 16.

FFiigguurree 1155:: PPLLSS

ffeeeedd ppuummppss

pprriimmiinngg ssyysstteemm

FFiigguurree 1166::

TThhee PPLLSS ffeeeedd

ppuummppss ddrraaww

ssoolluuttiioonn ffrroomm

aa rreellaattiivveellyy

ddeeeepp ppoonndd


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2.13: STOCK HOLDING

Because of the remoteness of the site, there is an abnormally high stock of extractant on site,

Figure 17. Dialogue has been opened with the supplier, BASF, to stock the extractant in country.

This will improve cash flow significantly.

FFiigguurree 1177::

EExxttrraaccttaanntt

uusseedd iinn tthhee

pprroocceessss

2.14: DOSING OF EXTRACTANT

Many plants pump extractant to the process. At Benkala, the container is lifted to the floor of

the mixer and the extractant fed by gravity.

2.15: CRUD

Crud has not appeared as yet, as a result, the crud filter press is lying idle, Figure 18.

FFiigguurree 1188::

CCrruudd ffiilltteerr

pprreessss

aawwaaiittiinngg uussee


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2.16: SYNERGIES TO BE DERIVED

If a similar plant or a plant comprising multiple lines of this plant is built, significant cash held in

stocks can be avoided. An agreement can be reached between the two plants where they hold

separate spares such as:

Cathodes Anodes Mixer mechanisms Electrolytic cells tanks, Figure 19

And share between them when the need arises. Such an agreement can improve cash flow

considerably.

FFiigguurree 1199:: TTaannkk ffoorr aann

eelleeccttrroollyyttiicc cceellll

2.17: PRODUCTION PROFILE

On the day of the plant visit, production was still being ramped up, but Benkala was already

harvesting 20 tonnes of cathode per day, Figure 20. This is considered to be an average start up

for such a plant.


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FFiigguurree 2200:: FFiinniisshheedd ppllaatteedd ccooppppeerr aatt BBeennkkaallaa,, aawwaaiittiinngg eexxppoorrtt

33:: AACCKKNNOOWWLLEEDDGGEEMMEENNTTSS::

The author wishes to express his gratitude to the management of the Kazakhmys projects team

on the Aktogay project for offering him such an opportunity to visit the newest heap

leach/SX/EW plant in Kazakhstan. This trip offered a new insight of how simplicity and

practicality can add shareholder value.

The hospitality of Kazcopper is deeply acknowledged, it was beyond compare. The discussions

with Kazcoppers COO, Adil on the journey to and from the site was an education by itself, and

highly appreciated. His pragmatic approach to project management and implementation is

exactly what is needed to make such low grade deposits payable. Such logical methodology to

project execution instilled tremendous confidence in the author. His indomitable insight of

regulatory requirements within Kazakhstan is second to none.

The humour of my colleagues Mark and Andrew must be mentioned for keeping me awake,

alert and active during the arduous trip to the mine. This report is the culmination of their joint

contributions in that respect.

Ramoutar (Ken) Seecharran

Process Plant Manager

Aktogay

Documents

Benkala Mine Visit Report