Auram Motorized Machinery

Aureka and the Auroville Earth Institute has been active in developing a range of motorized machinery for block-making to encourage the on-going use of CSEB in the changing labor environment and to accelerate production speeds. The motorized machinery now available include a soil crusher, a mixer, and a semi-automatic press.


The Auram Crusher is a soil crusher for use in the production of compressed stabilized earth blocks (CSEB), stabilized rammed earth, or other earth construction techniques. It is suitable for dry soils only: wet or moist earth must be dried before crushing and the earth must not contain roots. Occasional stones up to 50 mm (2-inches) diameter are permissible.

- Four wheelbarrows of 50 liters capacity are pushed up a ramp to load the hopper. The hopper has an adjustable opening to control the quantity of soil deposited onto the in-feed conveyor.

- An out-feed conveyor takes the crushed soil away from the crusher.
- The stand for the out-feed conveyor is mounted with a soil deflector, so as to consolidate a larger pile of soil.

- Maximum theoretical: 12 m3/hour, if the crusher is loaded to its maximum capacity with a soil totally free of roots.
- Typical practical: 5 to 7 m3/hour, depending on the loading speed, the soil quality, and the presence of roots.

Manpower Requirement:
- 7 to 8 workers: 1 machine operator/supervisor and 6 to 7 people to fill, transport, and load the wheelbarrows of soil into the hopper.

- The crusher has inflatable wheels so as to be moved easily on site or transported behind a tractor.
- The maximum towing speed behind a tractor is 20 Km/hr. For highway, the mixer must be loaded onto a trailer or truck.
- One end of the in-feed conveyor is attached to the crusher, the other end rests upon two small wheels.
- Both the crusher and the in-feed conveyor can be moved on site with a crew of 7 to 8 people.
- The out-feed conveyor has small wheels, for independent maneuvering.

Prototype of the Auram crusher*
* The prototype had a diesel engine, but new models have an electrical motor.


The Auramix 5000 is a continuous output mixer featuring raw material metering and adjustable flow rate, internal water sprayers, equipped with an in-feed conveyor belt. Three user-adjustable hoppers, one each for soil, sand, and stabilizer (cement or lime) are positioned at the front of the conveyor belt. During set-up, the appropriate material ratios, the material delivery rate, and water flow-rate are established. The hoppers deliver the user-set ratio of [soil: sand: stabilizer] onto the conveyor, which delivers them into the rotating horizontal drum, where they are initially dry mixed, and finally mixed with the addition of a fine water spray. A perfect moist mixture emerges from the output end of the mixing drum ready to be pressed into blocks or used for rammed earth construction.

Adjustable Metering System Details:
- Three dry-material hoppers (for sand, soil, and stabilizer) are positioned at the front of the in-feed conveyor belt. Gates at the hopper bottoms control the dry material ratio. The stabilizer hopper (for cement or lime) is mounted with a vibrator to assure consistent flow.
- A Rotameter and pressure pump assures the flow-rate of water, delivered as a fine spray within the mixing drum, is constant.

Operation Sequence:
- Soil and sand must be dry, free from lumps and stones, free from organic material, roots, leaves, topsoil. The Auram Crusher is optimized for use with the Auramix 5000 and is highly recommended for processing lumpy earth. Stabilizer must also be dry and lumpfree.
- Three to four workers continuously load soil and sand into hoppers with 50-liter wheelbarrows. Optionally, a skid steer, such as a Bobcat(R), fitted with a front bucket can be used, reducing the manpower requirement.
- One worker pours stabilizer into its hopper as needed.
- During set-up the [soil: sand: stabilizer] ratio, the water-flow rate, and the in-feed conveyor rate, are adjusted to achieve the proper mixture consistency, moisture, and output requirements.
- Dry mixing occurs initially for a few seconds at the head of the drum prior to subsequent water addition within the rotating drum.
- The mixer continues moist-mixing with water, resulting in a consistent mixture continuously emerging from the output end of the drum, ready for immediate use in a block press or for rammed earth construction.

- Mixer output can be adjusted anywhere from 4 to 7 m3/h by means of an adjustable pulley on the in-feed conveyor. Please note that the material ratio for [soil: sand: stabilizer] is fixed and is not affected by changes in output, but the water flow must be adjusted: increase the water flow-rate when you raise the output, decrease the water flow rate when you lower the output.
- Manpower requirement: 6 to 7 workers (1 machine operator/supervisor and 3 to 4 workers loading soil and sand with 50-liter wheelbarrows into the hopper).
- One worker feeding stabilizer into its hopper and one worker assistant for miscellaneous tasks.
- A skid steer can reduce the manpower requirement.
- Additional labor is required to operate a soil crusher, or screen, as necessary.

- The mixer has inflatable tires that can be lowered into position for on-site maneuvering and/or to be transported from site-to-site behind a tractor. These wheels can be raised when the mixer is in use.
- The maximum towing speed behind a tractor is 20 Km/h, along low traffic volume roads (i.e. rural roads).
- For highway and long-distance transportation, the mixer must be loaded onto a trailer or truck.
- The in-feed conveyor/hopper assembly is fitted with small wheels for on-site maneuvering only.

Hopper Options:
- It is crucial to purchase the mixer with the appropriate hopper assembly (either for manual or mechanized feeding): the metering system, which controls the mix ratio of dry materials, is integrated with the hopper assembly. The hopper/metering system is indispensable for correct mixer operation.


The Auram Press 4000S is a semi-automatic compressed earth block (CEB) press which is based on the successful design of the Auram 3000 manually-operated CEB press, of which more than 1000 have been sold worldwide. With the ingenious lever/cam/roller design a maximum of 200 kN peak force on the block surface is achieved with a minimum amount of electrical power.

- Maximum theoretical: 1000 blocks 240 or 1000 blocks 290 per hour (500 strokes per hour).
- Typical practical with 8h daily production: 700 to 800 blocks per hour, according to the speed of the operator.

Manpower Requirement:
3 workers with in-feed conveyor.
- 1 press operator to start and control the production cycle.
- 1 worker to offload blocks from the roller conveyor and stack blocks on the pallets.
- 1 worker with pallet jack to move the loaded pallets to the initial curing area (near the press).
If in-feed conveyor is used without the Auramix 5000, the 2 extra workers will load the hopper of the in-feed conveyor.

It is highly recommended to purchase these accessories so as to obtain optimal productivity for the press:
- In-feed conveyor to transport the soil from the Auramix 5000 into the press hopper.
- Out-feed roller conveyor to move the finished blocks away from the press.
- Hopper for in-feed conveyor is required only if the Auramix 5000 is not used.
- Inflatable wheels and a tow hitch for easy transportation. (The maximum towing speed behind a tractor is 20Km/h along low traffic volume roads, i.e., rural roads. For highway and long-distance transportation the Auram Press 4000S must be loaded onto a trailer or truck.)

The following blocks can be produced on the Auram Press 4000S:
- Double block Plain or Hollow 240 (one block per stroke) size 240 mm x 240mm
- Plain 240 (two blocks per stroke) size 240 mm x 115 mm
- Plain 290 (two blocks per stroke) size 290 mm x 140 mm
- Hollow 240 (two blocks per stroke) size 240 mm x 115 mm
- Hollow 290 (two blocks per stroke) size 290 mm x 140 mm
Block height can be 90 mm or 100 mm.

Hollow Double Block 240

Plain Block 290

Plain Double Block 240

Hollow Block 240

Hollow Block 290

Plain Block 240

Prototypes of the Auram press 4000 (semi-automatic) with the Auramix 5000

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