the stendafjellet rock quarry and underground waste
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Singapore – 11 November 2016
The Stendafjellet Rock Quarry and
Underground Waste Disposal site
Frode Siljeholm Arnesen, MSc.
Senior Engineering Geologist
Multiconsult ASA, Bergen, Norway
Stendafjellet Rock Quarry and Underground Waste Disposal Site – Frode S. Arnesen
Singapore – 11 November 2016
Stakeholders
Owner: Fana Stein & Gjenvinning Holding AS/ Fana Rock and Recycling
Holding LTD (FSG)
Managing Company: Fana Stein & Gjenvinning AS/Fana Rock and
Recycling LTD (FSG)
Land Owner: Hordaland County
Design, geological and environmental engineering:
Multiconsult ASA, Bergen
Stendafjellet Rock Quarry and Underground Waste Disposal Site – Frode S. Arnesen
Singapore – 11 November 2016
The Stendafjellet Quarry and Depositing site is a story of
commercial success
• The setting
• Geological Conditions
• Products
• Future development
Singapore – 11 November 2016
Location of site near Bergen, Norway
Singapore – 11 November 2016
All cities use aggregate
• Norwegian average usage of aggregate is more than one ton a year.
• The local aggregate market of Bergen is in the range of 300 000 tons per
year.
• Aggregates is produced locally or delivered to the city by boats.
Singapore – 11 November 2016
Fana Stadion was once a Quarry
Singapore – 11 November 2016
Høiehallen athletics hall, a former quarry tunnel
Singapore – 11 November 2016
Rådalen quarry and landfill site
Singapore – 11 November 2016
Former crusherplant was relocated
Singapore – 11 November 2016
Situation today, new incineration plant
Singapore – 11 November 2016
Landfill replaced by agriculture
Singapore – 11 November 2016
New location for quarry and depositing
Singapore – 11 November 2016
The nearby hill Stendafjellet has good quality rockThere was already a tunnel and a water storage cavern inside the hill
Singapore – 11 November 2016
Early design
Singapore – 11 November 2016
Visible footprint
Singapore – 11 November 2016
Pukkverk under jord
Primary chrusher
Secondarychrushers, screening and conveying
Crusher plant and aggregate distribution
Singapore – 11 November 2016
Vertical section of plant
Dato: 05.10.2016 FSG Pukkverk Side: 21
22 different grain sizes is accessible
Singapore – 11 November 2016
Map of cavernsand tunnels
Singapore – 11 November 2016 Dato: 05.10.2016 FSG Pukkverk Side: 21
Dump shaft is established to chrusher pocketVentilation and emergency escape adit through short shaftto terrain from top level
Singapore – 11 November 2016
Groundwater control
• The average permeability of the rock mass is generally
low ( 10e-7m/s).
• There are systematically placed drilled wells in different
distances surrounding the site.
• The groundwater level is registered automatically.
• Chemical content of groundwater is tested and reported
annually.
• The small quantity of water pumped out are generally
cleaner than water drained from the traffic tunnels in
Bergen city.
Singapore – 11 November 2016
Rock blasting methods for Quarrying underground
Top header is excavated by drill and blast, but the contentof dust are high.
Benching requires special attention to:
• Minimize fines.
• Geometrical control.
• Proper block size for existing crusherplant.
• Bench height must adapt what can practically be scaledand supported with available equipment.
• Limitation of access is determined by safety in thecavern.
Singapore – 11 November 2016
Bech blasting experiences
• Maximum 76mm borehle diameter, preferably 51 mm contour charge.
• Usage of evenly distributed blast agent with high detonation velocity.
• Denser drilling than normally recommended.
• Blast agent usage below 0,4kg/m3.
• Bench height maximum 13m.
• Top Bench + 3 benches.
• There are a mid level access from both sides of the cavern.
Singapore – 11 November 2016
Ventilation
• There are one vent shaft in each end of the cavern system, one having a
suction fan ensuring underpressure independent of wind direction.
• Air inlet is through the low level tranportation tunnel.
• Vent shafts serves also as escape routes.
• Rock drilling requires installed dust control, or use of water.
Singapore – 11 November 2016
Rock support
• Scaling by demolition rig, reaching 25m upwards.
• Bolting in walls by remote controlled drill rig.
• Mainly use of grouted bolts.
• Top bench : Systemetic rockbolts 4 – 5 m long and steel fiber shotcrete.
• Walls: Scaling and spot bolting, occasionally shotcreting.
• Grouted cable bolts when required.
• Fracture zones supported by fiber shotcrete, bolts and reinforcement.
Singapore – 11 November 2016
Sub-title
Typical weakness zone in wall
Singapore – 11 November 2016
Sub-title
Where support is discussed
Singapore – 11 November 2016 Dato: 05.10.2016 FSG Pukkverk Side: 21
Singapore – 11 November 2016
Experiences from quarrying
• 5 of 8 caverns have very good rock conditions.
• The last three caverns has successively poorer rock, due
to fracturing.
• Fracture zones with swelling clay requires much more
extensive support.
• Excavation and crushing gives a fair profit.
• Depositing is a much more profitable
activity.
Singapore – 11 November 2016
Conditions for profitable underground quarry:
• Good Rock Quality, UCS > 130 Mpa, Q > 10.
• Acceptable hydrological conditions, a system of groundwatersurveillance and testing must be established.
• Existing market close by, enabling effective transportation.
• Other competing quarries have longer transport distances.
• Neighbour houses minimum 250 m from tunnel opening, and restrictions on future usage of area above caverns.
Singapore – 11 November 2016
Criteria necessary for depositing
• Inward flow of water.
• Groundwater control and testing, annually.
• Low permability rocks, small water volumes.
• Terrain is not harmed by low groundwater table.
• Drainage to low pump sump, pumping water to approvedlocation.
• Acquiring approvals for deposisting, including reducedtaxes for depositing compared to landfill usage.
• No harmful or explosive gases from deposited materials.
Singapore – 11 November 2016
Examples of deposited materials • Foundry sand
• Sand blasting sand
• Iron sand from metal recycling
• Heat treated drilling mud
• Microsilica dust from smoke filters
• Concrete with and without PCB
• Bricks with and without PAH ( chimneys)
• Construction waste
• Glass from refurbishment of housing
• Soils with dangerous contamination
• Removed materials with asbestos content (bagged)
• Sand and materials for street and drainage cleaning
• Fluff – remnants from car and metal recycling
• Contaminated soils from city and street excavations
Singapore – 11 November 2016
Experiences from depositing so far.
• 55m high cavern requires procedures for filling due to
stability issues.
• Dust must be controlled by ventilation.
• Deposited materials has very low permeablity.
• The small quantities of inleaking water have limited
contact with the deposited soils.
• The level of water contaminaton from drainage water is
of same scale as the ordinary drain water from roads in
the city.
Singapore – 11 November 2016
Future layout
Singapore – 11 November 2016
North–south section
Top level ofdepositing
Singapore – 11 November 2016
New highway crossing under the siteMitigation of groundwater effects is planned
Mitigation zone along highway section
Singapore – 11 November 2016
Thankyoufor
yourattention!
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