Australia
It is our understanding that you are interested in obtaining information about the liquefaction potential of materials which are not listed in Appendix A of the BC Code and of coarse grained materials which are liable to liquefy during transport.
Canada
a) Before any test is conducted between DSC 5 and DSC 6, there is an urgent need to define a typical fine granular mineral and very coarse materials;
b) The potential for liquefaction of a cohesionless solid bulk cargo (very coarse materials?) is related to the intensity of dynamic loadings, the in situ stresses in the hold of a vessel, the grain size characteristics of the solid bulk cargo, the shear strength and the in-place density in the hold of the vessel;
c) The shape of laboratory liquefaction test data curves for different solid bulk cargo (fine granular minerals) types can vary quite widely especially for solid bulk cargoes containing small amounts of minus of 0.075 and 0.002 mm grain diameters; and,
d) Liquefaction analyses require careful selection of all input parameters and the interpretation of analytical results should be made on the basis of experienced professional judgement.
Coordinator's comments (5) - Regarding comments by Canada:
a) Taking the results of the relevant research into consideration, for the evaluation of the effectiveness of the liquefaction potential test, we would like to ask you to find out the solid bulk materials of which the effective size D10 is in the range of 0.2 mm to 1 mm.
b) We agree with your comments in general. However, we consider that for the purpose of the evaluation of liquefaction potential of cargoes, it is not practicable to introduce the parameters related to the condition of stresses. Instead of the introduction of these parameters, procedure for compaction is determined in the laboratory test procedure and safety margin is involved in the criteria on judgment.
c) We understand your comments that it is premature to introduce a judgment based only on the effective size of a material. [If there was very specific material of which the effective size is bigger than 1 mm and which contains several percents of fine particles less than 0.075 or 0.002 mm, the primary judgment of our method could not be able to apply for the material.] Is it preferable to conduct some experiments using the materials of which the grain size distribution is artificially controlled, to evaluate the applicability of the primary judgment method based only on effective size? We would like to invite your comments on this issue.
d) The test procedures listed in Appendix D of the BC Code were developed based on the accumulated experience and the criteria on judgment were determined taking the safety margin into account. We are of the opinion that it is not necessary to analyze liquefaction phenomena in the cargo hold taking so many factors into account because the judgment of our method is based on the similar principle and equivalent safety margin of the Proctor/Fagerberg method.
Poland
It's clear, fully agree.
3.2. Looking for materials
We will look for materials suitable for the tests and send you the characteristics of the materials later. This work will continue in the period of second round of the C.G.
Action requested : C.G. members are invited to look for materials suitable for the tests. Status of the materials are as follows
(A) comparatively fine granular materials which are transported in bulk regardless of moisture content;
(B) comparatively coarse granular materials which are subject to the requirements for liquefaction materials;
(C) comparatively fine granular materials for which the test procedures for measuring flow moisture point, i.e., the flow table test procedure and the penetration test procedure, are not applicable; and
(D) any other materials suitable for the tests by your consideration.
C.G. members are invited to provide the information on the materials. It is preferable to provide the information on the following characteristics.
(1) name of the material (sipping name, trade name, etc.);
(2) type of the material, e.g., mineral concentrate, granulated slags, etc.;
