Analyses of 17 minor elements in cassiterite, a common heavy mineral from fluviatile deposits in the Hatapang Area, Sumatra, Indonesia, by the inductively coupled plasma emission and the atomic absorption method are reported. Fe, Mn, W, Ti, Nb and Ta are present in significant quantities in the mineral, while low concentrations (<410ppm) of As, Cu, Mo, Ni, Pb and Zn were detected. The concentrations of other minor elements such as Ag, Bi, Cd, Co and In are below the limit of the detection by the method employed.
It was observed that in respect of amounts of minor elements except Mn there is a close similarity between cassiterite from the Hatapang Area and that from the Bangka Island.

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Uniaxial compression tests were performed upon 5 sample rocks to investigate effect of loading rate by constant strain rate method for a class I rock and stress-feedback method for the other class II rocks. Results show that strength increases with loading rate, and that stress-strain curve in the post-failure region at a higher loading rate will enclose those at lower rates.
The unloading compliance of specimen in the post-failure region was investigated by repeated unloading-loading processes. It is found that the inverse of compliance 1/γ decreases linearly with stress.
Based on the test results, a simple model which explains the effect of loading rate and the compliance change in the postfailure region was proposed. The model can also explain behaviours under constant strain (relaxation) and constant stress (creep) qualitatively, though it has some incompletenesses such as the inability of explaining strain hardening phenomenon.

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Seven red mud samples were studied and characterized to elucidate their surface state using extensive chemical and spectroscopic techniques. The result obtained are summarized as follows:
1) Liquid: solid ratio of red mud varied between 30-70 weight%.
2) pH values of supernatant solutions varies between pH=12-13. Acid-base titration of the supernatant solutions gave end point of pH=9.
3) Cyclosizer classifications showed that red mud is made of super fine particles, 70% of which were smaller than 11.3 micrometers.
4) Emission spectrographic analysis indicates the presence of the following elements in red muds: Fe, Al, Si, Ca, Mg, Na, and Ti as major elements; Cr, Mn, V, and Zr as minor elements.
5) X-ray diffraction analysis allows the following mineral species to be “definitely identified” in red muds: Hematite, Boehmite, Calcite. Tentatively identified mineral species are: Rutile (or Anatase), Jarosite, Christobalite, Siderite, Kroehnkite, Goethite, Azurite, Graphite, Hydrogrossilarite, Perovskite, Tridymite, Ulvospinel, and Concrinite.
6) EPMA shows that Titanium is almost homogenenously distributed in simple grains and also Titanium occurs together with Fe and Ca in all red muds.
7) X-ray and EPMA data confirm the universal presence of Ti, Ca, and Al while Fe is conspicuously absent from one sample out of seven.
8) It is established that Ti is associated with Fe and Ca rather than Al and exists in structures, such as simple Rutile (or Anatase) and Ilmenite, or complex grains of Perovskite or Ulvospinel.
9) IR spectra of red muds identified the existence of the vibration of adsorbed water, Si-O and OH of Boehmite, Calcite and metal-oxide.
10) DTA-Tg analysis showed dehydration of adsorbed water, dehydroxylation of red muds, and decomposition of Calcite in the endothermic pattern.
11) Titanium on red muds was also identified by the binding energy of 2p_1/2 and 2p_3/2 of Ti by ESCA.
12) The isoelectric point of red muds is located at about pH=9, being influenced by Hematite or Calcite.

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Strong reductive roasting, which aims at the high reduction rate of iron, by a coal-containing pellet method have been conducted, for garnieritic ores. The influence of various fundamental factors was investigated on the reduction rate of iron and the grade of residual carbon. Some results obtained are as follows.
A reoxidation method was suitable as a method for determining the reduction rate of iron, because it had no influence of enclosing metallic particles by recrystallization.
Lignite and bituminous coal were suitable to obtain a reduced pellet with high reduction rate of iron and low residual carbon, in comparison with anthracite and cokes.
An addition of coal over some extent was required to obtain the high reduction rate of iron, and a mixed pellet method. in which two types of pellets with a high coal content and little or no coal content, respectively, were mixed, will be effective to obtain a reduced pellet with high reduction rate of iron and low residual carbon.
A high recovery rate of sulfur into reduced pellet was achieved when sulfur was added to ores with coal.

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