Reconnaissance Drilling for High-Grade Silica Sand in the Tayma-South area, Kingdom of Saudi Arabia: Results of Work Completed in 2001
Rushdi R. Al-Dawawsi, Hassan M. Al Marzouki, Adeeb H. Ziyadi, Mamdouh O. Abu Safiyah,
Rafat A. Ghandourah, and Hasan Kh. Al Madi
Reconnaissance drilling for high-grade silica sand in the Tayma-South area was undertaken by Saudi Geological Survey geologists west of the NS-trending highway between Tayma and Madinah al Munawwarah from May 15 to July 14, 2001, and resumed from September 29 to October 17, 2001. This work was a continuation of earlier exploration in the area, completed during the first half of 2000 and reported on previously. In 2001, over an estimated area 30 km long by 6 km wide, 50 diamond drill holes (each 24-30 m deep), totaling 1,151.55 m, were positioned on the 19 parallel lines trending N.65°. Channel sampling for one quarter of the core taken at 7.5 to 10-m length intervals, or more when visual assessment indicate color homogeneity. One hundred ninety-six samples were prepared in the site by means of a portable sample divider. After preparation for sand fractions and heavy minerals removal, chemical analyses were conducted at the SGS Jeddah laboratory. Chemical analysis results demonstrate that sandstone contains SiO2 between 96.3 and 99.18 percents, with an average of 98.02 percent; Al2O3 is between 0.4 and 1.39 percents, excluding two values of >1.75 percent Al2O3, and average of 0.97 percent; Fe2O3 is between <0.05 and 0.10 percents. Other oxides are negligible. Main impurities such as clay were removed by water-washed process, for sandstone samples with >1.75 percent Al2O3, therefore silica increased between 2.2 to 5.3 percent, and alumina content decreased between 1 to 3.48 percent. Color measurements on water-washed samples showed favorable values. Eighteen samples analyzed for particle-size distribution studies show poor to moderate sorting. The weight percentage of common sand size required by the glass industry is: for 0.1-0.5 mm between 59 and 81 percents, and for 0.1-0.63 mm between 61 and 88.4 percents. Grainshape microscopic study showed subrounded to subangular grains. Heavy minerals removal by means of a Gold Hound machine demonstrate that the sandstone comprised less than 0.1 percent of the following minerals: magnetite, hematite, ilmenite, and rutile, together with traces of pyrite and silicate grains. Measured resources over an area of 208 km2 with a depth of 30 m are about 6,240 million cubic meters.
Al-Dawawsi, R.R., Al Marzouki, H.M., Ziyadi, A.H., Abu Safiyah, M.O., Ghandourah, R.A., and Al Madi, H.Kh., 2003, Reconnaissance drilling for high-grade silica sand in the Tayma-South area, Kingdom of Saudi Arabia: Results of work completed in 2001: Saudi Geological Survey Open-File Report SGS-OF-2002-11, 29 p., 19 figs., 12 tables, 2 apps., 1 plate.