Recovery & recycling of excavated tunnel waste

Kolkata, India, 2021-Sep-23 — /EPR Network/ — Rock excavated in an average tunneling project is often considered waste and mostly finds its way to a landfill. Depending on the geology and excavation method used, the extracted material can have significant quality deviations and may be unsuitable for use as construction aggregates because of varying geometric, physical and chemical characteristics. However, if this waste is suitably treated and processed, it can be recycled and used as a substitute for conventional mineral aggregates at a construction site.

Excavated rock utilised as a concrete aggregate is good for both environment and business –

• Generates more value than simply being dumped in a landfill or filling up old quarries
• The utilisation of rock is usually near a processing facility or a concrete batching plant which significantly reduces the need for transporting aggregate
• Lesser need for landfills creates a positive environmental impact
• The project being almost self-sustained in construction aggregates results in the investment cost of the facility getting repaid quickly.

Tunnel Boring Machines (TBM) are one of the most popular methods of tunneling. TBMs create rock particles with excessive fines – a problem affecting the quality for both subbase and concrete aggregates. Mechanical screening (scalping screener), which usually is the first stage of processing tunnel rock in a Tunnel Boring Machine (TBM) removes rock particles below 16-20mm diameter.  This process aims to get rid of the high amounts of fines that are created by TBM tunneling in hard rock.

By 2018, there were seven confirmed projects worldwide that were recycling tunnel rock (TBM) on an industrial level. These projects are all placed in hard rock, the details of which are given below: [1]

Project	Country	Year	Km	Million tons(metric)	Recycling[%]	Diameter(mm)
Zugwald	Switzerland	NA- 1998	9.5	1.2	16%	>16
Gotthard Base Tunnel	Switzerland	1999-2016	57.1	28.7	23%	>0
Koralm KAT2	Austria	2013-2023	21	8.6	17%	>16
Follo line	Norway	2016-2021	19.5	9	10%*	>20
Lötschberg	Switzerland	1999-2007	34.6	16	29.1%	>0
Linthal	Switzerland	2010-2015	3.7	1	100%	>0
Nant de Drance	Switzerland	2008-2016	5.5	1.14	25%	>0

The environment-friendly, patented wet processing technology from CDE addresses all the issues above and has the following key features:

• Zero waste discharge to atmosphere
• 95% recirculation of process water
• Removal of scrap such as wood chips, plastic, other trash material
• Minimum space for installation
• Skid mounted portable units
• Suitable for shifting from location to location
• Minimum unit power requirement
• Less than 80db noise level

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Company Name: CDE Asia

Address: Ecospace Business Park Block 4A/Floor 6, Action Area II New Town Rajarhat Kolkata 700 160 India

Phone: +91 33 3029 3800

Fax: +91 33 3029 3802

Url: https://cdeasia.com/                               

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