Ikamva Deepening Project Environmental Engineering Planning 10 June 2021 - Enver Hoosen - Environmental Engineering Manager
←
→
Page content transcription
If your browser does not render page correctly, please read the page content below
Ikamva Deepening Project
Environmental Engineering Planning
10 June 2021
Enver Hoosen – Environmental Engineering Manager
Introduction – Kloof Operation
• The Kloof Operation is situated in the Magisterial District of Westonaria, some 60 km
west of Johannesburg at latitude 26˚ 24’S and longitude 27˚ 36’E, in the Gauteng
Province of South Africa.
• Kloof consists of five Shafts, Main, 3, 4, 7 and 8 Shafts. The deposit is accessed from
surface using underground mining methods to 45 Level (the lowest working Level) at
No.4 Shaft, approximately 3,347 m below surface.
2
www.sibanyestillwater.com
Introduction – Ikamva Shaft Deepening Project
• Kloof Ikamva Shaft (K4) has mining infrastructure down to 45 Level. Mining currently
takes place between 39 and 45 Levels.
• The Kloof No. 4 Shaft Deepening Project targets the Ventersdorp Contact Reef
(VCR) from 45 level down to 47 level and to the north of the 51 line, which is situated
below current infrastructure.
• The project fits into the Kloof Strategic plan by accessing below infrastructure
ground thus extending the life of No. 4 Shaft and adding to the Kloof Ore Reserve
base.
• Various concept designs were considered and the selected method to access 46
and 47 Level was through an access ramp extending from 45 Level in the current
workings.
• Once in position on 47 Level a raise-bored decline shaft would be established for
the permanent hoisting of rock and material with the access ramp being equipped
with a chairlift for personnel transport to and from 46 and 47 Level.
3
www.sibanyestillwater.com
Ikamva Shaft Location
4
www.sibanyestillwater.com
Project Original Design Isometric View
Winder Installation
45 to 46 Level - Mechanised development -
100 chairlift decline (equipped with a chairlift
for men access in the permanent condition)
46 Level (First cross-
cut to reef)
46.5 Level
46 to 47 Level - Mechanised development -100
chairlift decline(equipped with a chairlift for men 46.5 to 47.5 Level RBH
access in the permanent condition) shaft -34º
47 Level (First cross-
cut to reef)
5
www.sibanyestillwater.com
Problem Statement
• Only one end was mined in the Ikamva Deepening section prior to August 2019.
• This increased to two ends in August 2019 and three ends in November 2019.
• Four ends were mined in December 2019.
• The increase in the number of ends being mined resulted in an increase in the
ventilation and cooling requirements, which continued as the ends advanced.
• Two ends were mined simultaneously since February 2020 due to ventilation and
cooling constraints.
6
www.sibanyestillwater.com
Summary of Heat Generated and Short Term Cooling Installed
• The sum of equipment introduced over and above the original design
equalled to 900Kw.
• During this period additional cooling over and above original design equalled
to 454Kw.
• This resulted in a short-fall of 446Kw cooling.
• Additional cooling planned for 278Kw in workshop on 45 Level to reduce intake
temperature.
• The cooling deficit to achieve original design criteria is 168Kw.
• The above would accommodate mining to December 2020.
7
www.sibanyestillwater.com
Ventilation Layout – 45 Level
8
www.sibanyestillwater.com
Ventilation Layout – 46 Level and Below
9
www.sibanyestillwater.com
Key Ventilation Design Parameters
• Sibanye Stillwater battery limit for temperature 31.0º wet bulb and / or 37.0ºC
dry bulb.
• Temperature >31.0 and 206 W/m2.
• Virgin Rock Temperatures (VRT) > 54ºC.
• Compliance to Airborne Pollutant COP (Silica and Diesel Particulate Matter
exposure).
10
www.sibanyestillwater.comVentilation and Cooling Constraints
• Failure of the hexagon ducting used in sections of the decline resulted in excessive
leakage into the return airway.
• Only service water available for cooling, at a temperature of 14ºC, with limited
return pumping capacity.
• The use of 6-7 vehicles (2 on 45 Level and 5 below 45 Level) resulted in high heat
loads, especially since the introduction of the dump truck in November 2019.
• Air used to ventilate the development on 46 Level is re-used to ventilate the
decline.
• The ventilation layout could not support the mining of additional ends on 46 Level
due to the above.
• An action plan was implemented to improve conditions, including investigating
various ventilation layout scenarios using VUMA modelling software to simulate
progressive development stages.
• VUMA modelling to be used to determine the number of ends which could be
mined under current conditions, as well as following completion of planned actions
during the different development stages.
11
www.sibanyestillwater.comShort Term Action Plan
Planned Actual
Concern/Item/Hazard Action Required
Completion date Completion date
Additional heat load from
Move compressor to RAW position Dec 19 Dec 19
compressor in decline
Install spot cooler above 46 Level 07 Feb 20 07 Feb 20
No additional cooling available in
Install spot cooler below 46 Level 03 Jun 20 03 Jun 20
decline
Install spot cooler on 46 Lev 14 Jul 20 14 Jul 20
Failure of hexagon vent columns, Replace ducting
causing excessive leakage into 21 Aug 20 21 Aug 20
RAW Replace bends
Spot cooler failure on 45 Level Replace spot cooler 20 Jul 20 20 Jul 20
Install closed loop piping between 45
Lack of chilled water for cooling Jan 21
and 46 Levels
Ventilation layout not supporting Confirm layout for 46 Level development
20 Jul 20 20 Jul 20
mining of additional ends (VUMA stage modelling)
12
www.sibanyestillwater.comMine Ventilation Simulation Software
• Various mine ventilation simulation software packages are available.
• Used in the planning, design, energy optimisation, management and real-time
monitoring of mine ventilation networks across the globe.
• Software utilises a combination of thermodynamic and aerodynamic,
interactive mine-network modelling algorithms that can be customised for any
mining system or orebody.
Solving complex ventilation systems with many features.
Fan selection and optimum fan location selection.
Determining airflow requirements.
Determining effect of improvements / changes to overall system.
• A number of reports can be generated for different parameters.
• Network simulation provides airflow distribution throughout the network and the
pressure required.
• Software is designed to accurately simulate airflow, heat loads, gases
(including radon), dust, blast clearance and fires.
• Allows engineers to plan, design, operate and control the ventilation and
cooling systems.
13
www.sibanyestillwater.comKloof Integrated VUMA Model
Effect of changes at an individual shaft can be simulated for the entire mine.
14
www.sibanyestillwater.comVuma Modelling of Decline Project – Scenario 1
Development with short term changes
August 2020 December 2020
Decline Decline
46.5 Ramp 46.5 Ramp
46/52 XCN Reverse 46/52 XCN Reverse
46/52 FWD N
46/52 FWD N
Available ends reduce in December 2020 due to environmental conditions.
15
www.sibanyestillwater.comVuma Modelling of Decline Project – Scenario 2
Effect of raise boring vertical dam between 46 and 46.5 Levels
October 2020 – No Raise boring October 2020 – Raise boring 46-46.5 Levels
46.5 Ramp Decline 46.5 Ramp
Decline
46/52 XCN Reverse 46/52 XCN Reverse
46/52 FWD N 46/52 FWD N
Introduction of the raise borer on 46 Level affects all ends except the footwall drive.
16
www.sibanyestillwater.comVuma Modelling of Decline Project – Scenario 3
Vent Hole between 45 and 46 Levels
November 2020
Decline Proposed position of vent
hole – completion November
2020
Original position of vent hole
– completion April 2021
46/52 FWD N
Commissioning of the vent hole results in improved environmental conditions on 46
Level as well as development below 46 Level.
17
www.sibanyestillwater.comVuma Modelling of Decline Project – Scenario 3
Vent Hole between 45 and 46 Levels
November 2020
Commissioning of the vent hole results in improved environmental conditions on 46
Level as well as development below 46 Level.
18
www.sibanyestillwater.comVerification of Scenario 3 – 46 Level and Below
19
www.sibanyestillwater.comEnvironmental Conditions Post Completion of Vent Hole
Working Place Previous Temp (ºC) Current Temp (ºC)
46/52 FWD Nth 30.0/33.0 29.5/35.5
46/52 Tippler XC 31.0/35.0 30.0/32.0
46 Lev Workshop 30.0/33.0 28.0/34.5
46/52 Dam 30.0/33.0 29.0/34.0
46/52 Decline 31.5/34.5 (Stopped) 29.0/31.0
46.5 Ramp Stopped (>32.5) 30.0/34.0
Note:
• Previous conditions were measured with not all working places being ventilated /
available concurrently, and with three cooling cars operating in the decline.
• Current conditions are with all working places being ventilated and available, two
cooling cars operating with the third being relocated to the 46.5 Ramp. Not all ends
were working when measured.
www.sibanyestillwater.comConclusion
• The use of simulation software proved to be a valuable planning tool for improving
environmental conditions in the Decline Project area.
• Simulation assisted with the design and selection of project fans (high efficiency).
• The number of available ends increased after scenario 3 was implemented.
• Reliability of simulation proven – high level of confidence.
• Multi – shift blasting scenario to be used as part of risk assessment.
• Conventional planning to be verified using simulation software.
www.sibanyestillwater.comYou can also read
