Document Type : Original Research Paper

Authors

• Abdelrahem Khalefa Embaby ¹
• Yehia Darwish ²
• Samir Selim ³
• Darwish El Kholy ⁴
• Hani Sharafeldin ⁵
• Hussin Farag ⁶

¹ Associate professor, Al-Azhar University, Faculty of Engineering Mining and Petroleum Engineering Department

² Associate Lecture at Nuclear Materials Authority, Cairo, Egypt.

³ Professor at the Department of Mining and Petroleum Engineering, Al-Azhar University, Cairo, Egypt

⁴ Nuclear Materials Authority, Cairo, Egypt.

⁵ Lecturer, Mining, Al-Azhar University, Faculty of Engineering Mining and Petroleum Engineering Department

⁶ Lecturer at the Department of Mining and Petroleum Engineering, Al-Azhar University, Cairo, Egypt

Abstract

The younger granites of Gabal Gattar area, Northern Eastern Desert of Egypt, host hydrothermal uranium mineralization at the northern segment of Gattar batholith and along its contacts with the oldest Hammamat sediments. The host rocks display many features of hydrothermal overprint results in changing their basic engineering characteristics as a function of variations of the degree of alteration. Progression from less altered to altered and mineralized rocks as the result of the alteration processes was assessed by the chemical index of alteration (CIA). The CIA numerical values were calculated by   the molecular proportion of Al to the cations Ca, Na, and K. The studied rocks were divided into five grades according to degree of alteration and strength properties including: fresh (AG-I), slightly altered (AG-II), moderately altered (AG-III), highly altered (AG-IV) and very highly altered (AG-V). The strength properties of the studied rock units correlated well with the alteration grades assigned to them. That is, as the grade increased from AG-I to AG-V, abrasion resistance and crushability index increased, whereas compressive strength, slake durability and impact strength decreased.

Keywords

• Chemical index of alteration
• mechanical properties
• Hydrothermal alteration
• uranium mineralization
• Gattar area

Main Subjects

• Surface Mining