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Hazardous slopes protected with CATEX

Catex du Mont Bonvin

Mont Bonvin CATEX Modification in Crans Montana

CATEX (CAble for Transporting EXplosives) is a complete system for the preventative triggering of avalanches, operated by a pyrotechnician.

It consists of:

  • A wire cable loop passing over the various avalanche zones. The cable can be moved in both directions.
  • Pylons and equipment to support and guide the cable.
  • A drive station where the explosive charge is loaded and the cable is controlled.
  • A system for positioning the charge.

It allows an explosive charge to be put into position over an avalanche zone as and when required and in all weather conditions. The explosion of the charge creates a shock wave which, by the phenomenon of compression-depression, loosens the snow and triggers the avalanche.

Ski-slope CATEX :

Road CATEX :

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Crozats Catex cable route in La Plagne

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Cable route on Avalanche Triggering and Intervention Map

The route of the CATEX cable is at the heart of the system’s design.

We use the knowledge of local advisers who understand the particular problems as well as professionals and official organisations; to this we add our own experience in order to plan the route as close as possible to the zones to be secured. The pylons are positioned to ensure the best protection from natural risks while minimising the visual impact of CATEX.

Surprisingly, perhaps, the route is not definitively fixed. It is very simple, and inexpensive, to move a pylon, or to add an extension to an existing CATEX system to improve its effectiveness.

After using the CATEX for some time, it may become clear that a firing-point should be moved for a more effective clearing of the zone.

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Montaz Station

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Explosion

The MONTAZ CAble for Transporting EXplosives is the only remote avalanche control system which offers all of the following features:

– All-weather firing capability

– Ability to move the detonation-points according to the wind direction

– The effectiveness of firing above the snow

– Entirely automated deployment of charges allowing up to 20 simultaneous explosions

– A functional, accessible and ergonomic drive unit.

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A tower with a floating pulley

Our towers are :

-of tubular, galvanised steel

– of a diameter adapted to their load

– from 4 to 12 m in height

– transportable by helicopter

– able to be increased in height

– equipped with guy-wires to reduce strains and movement at the head of the pylon

– equipped with a ladder conforming to safety standards

– equipped with a safety line (approved EN353-2)

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Floatting Pulley

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Inclined support and inverted inclined support sheave assemblies

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Double support compression sheave assemblies

The line equipment supports and guides the cable and limits the risk of derailment.

It is all based around the Montaz 600 mm diameter sheave, which provides the best compromise between weight, rigidity, robustness and the need to adapt to the winding diameter of the cable. It has maintenance-free, closed ball-bearings.

We use several types of equipment, including:

– Floating pulleys, which can be fitted with a rime scraper

– Inclined support sheave assemblies

– Support compression sheaves assemblies

We can tailor the guidance systems to suit your particular needs.

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A 500m distance between towers

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Splicing

The cable is made of galvanised steel.

We select the right cable for each individual CATEX system, according to its length as well as the weight of the charges to be transported:

– 8 mm diameter, 3750 kg breaking strain; we tension the cable to 750 kg, i.e. a safety coefficient of 5.

– 9.5 mm diameter, 6250 kg breaking strain; we tension the cable to 1250 kg, i.e. a safety coefficient of 5.

With these tensions, the distance between pylons can be as much as 900 m, depending on the terrain.

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The drive station of “Croix des Verdons” Catex (Courchevel)

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A triple drive station in Les 2 Alpes

The drive station consists of:

– A set of guide sheaves to direct cables leaving the station

– A 3x2m platform with a railing compliant with safety standards

– Access steps with handrail

– An encased electric motor and a 600 mm rubberised drive-wheel

– A sensor to indicate the position of the charge (pulse-generator and counter)

– Two limit detectors

– A halogen projector

– An emergency stop button.

If it is hydraulically tensioned, it also has:

– A tower with guide rails for the motor frame

– A motor frame with sliding pads

– A tension group consisting of a hydraulic ram driven by a pump.

It can also be of fixed-tension type, in which case the motor-frame group is fixed to the drive station pylon

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The Command Console

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Patroler driving a Catex

The command console houses all the circuits for the operation and control of CATEX.

The console is 1 m wide, 1.10 m high and 0.4 m deep.

It contains the safety circuits, the automatic controller, the command touch screen, the manual drive control circuits and the variable-speed drive.

The variable-speed drive is adapted to the power of the motor, which is generally from 4 to 15 KW, depending on the route of the cable.

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Initialising the towers

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Selecting the firing-points

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Positioning of overhead cable markers

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Calculation of time lapse

Manual Control

This system allows the manual control of the CATEX, for testing, training or back-up control.

It enables the direction and speed of the cable to be controlled by the operator.

The platform lightning can be operated from the console.

An autonomous counter indicates the position of the charge on the cable.

The emergency stop button is easily accessible, being prominently placed on the control console.

Automatic Drive Control

Using the touch-screen of the controller, up to 20 charges can be transported; they are moved simultaneously to the selected firing-points in the quickest way possible.

Initialising the towers:

This is done when the equipment is put into service.

The Distance is measured by the number of turns on the guide sheave. This is the basic for controlling the CATEX.

Selecting the firing-points:

Up to 20 firing-points can be selected on the same cable. The controller indicates when to attach each charge.

The management programme for overhead cable markers.

Assisted calculation of fuse length, depending on the combination of selected firing points.

The selected firing points displayed on the CATEX map.

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Adjustement of the firing point

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Firing point shifting principle

The automatic control also provides one of the most valuable feature:

Adjusting a firing point.

This is particularly useful in situations where wind direction can alter the position of accumulation of snown.

So, our programme includes a “weather conditions” section, which allows the firing point to be shifted by several metres.

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View of Auron Manual Catex

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Manual drive station

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The cranks

We also provide “manual” CATEX systems.

The line equipment is technically similar to the other CATEX systems, and the drive unit is similar to a drive unit with a fixed motor frame (except that there is no motor) with a loose pulley tensioning the cable and two cranks on the guide-wheels frame to move the cable.

This type of CATEX is simple and economical; it is used for relatively small systems, where there is not a great height difference between the drive unit and the farthest point.

The platform complies with work regulations and there is plenty of space around the crank.

Advantages:

No drive motor, so it can be set up very rapidly.

The operation of the cranks is very ergonomic and can be done by a single operator. With two operators, the charge can be transported more quickly.

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Transportation by helicopter

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Civil engineering

We can carry out any works concerning the assembly and maintenance of our material:

– Construction work (drilling, foundations).

– Assembling the towers and the line equipments.

– Unrolling the cable.

– Cable work (splicing, replacing strands and shortening).

– Maintenance visits.

– Undertaking urgent repairs in any weather conditions.