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STABILISATION OF UNCONSOLIDATED BACKFILL

Objective

To investigate the technical and economical feasibility of stabilizing unconsolidated backfill. Methods such as grouting or freezing will be used. Design methods will be developed and suitable methods and materials will be tested both in the laboratory and in full scale field trials.

The unconsolidated backfill, comprising deslimed mill tailings or other granular materials, was widely used in the past in order to stabilize underground mine openings. Stabilization of this material would permit the extraction of adjacent ore in pillars with minimal loss of dilution, giving a significant economic gain from the increased recovery rate expected.

It is intended to investigate techniques for the stabilization of unconsolidated backfill and estimate the associated costs and benefits. Techniques considered will include grouting, freezing and other stabilization methods. An outside specialist in such techniques will be consulted and will evaluate the initial testwork proposals.

The partners will assess and develop methods of designing the strengths required to prevent failure of stabilized fill when exposed by adjacent mining. Numerical modelling techniques such as finite element and finite difference methods will be included in this assessment. A specifically tailored design method will be developed by Mining Italiana for use at Tara Mines.

Using the design method developed, the material strengths and extent of stabilization required for a full scale field trial will be determined.

Laboratory compressive and shear tests will be used to determine the most economic method of achieving the required strengths. The constitutive parameters of the stabilized materials (moduli, Poissons Ratio) will also be determined for input to the numerical models.

The monitoring and sampling methods required for a full scale field trial will be determined.

The partners will plan a full scale field trial using the most appropriate techniques and materials as determined previously.

Tara Mines, with cooperation from Mining Italiana, will conduct the full scale field trial and monitor the performance of the stabilized fill during adjacent mining, using the methods already developed.

The data obtained from the field trial will be analyzed and the developed design model calibrated.

Conclusions and final report will be produced.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

Mining Italiana SpA
Address
Via Chianesi 110
00128 Roma
Italy

Participants (1)

Tara Mines Ltd
Ireland
Address
Knockumber Road
37 Navan Co. Meath