Bulletin of the Geological Society of Malaysia 56, December 2010, pp. 61 – 66 /* Style Definitions */table.MsoNormalTable{mso-style-name:"Table Normal";mso-tstyle-rowband-size:0;mso-tstyle-colband-size:0;mso-style-noshow:yes;mso-style-priority:99;mso-style-parent:"";mso-padding-alt:0cm 5.4pt 0cm 5.4pt;mso-para-margin:0cm;mso-para-margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:10.0pt;font-family:"Calibri","sans-serif";}
Program Geologi, Pusat Pengajian Sains Sekitaran & Sumber Alam, Fakulti Sains & Teknologi, Universiti Kebangsaan Malaysia, 43600 Bangi, Selangor
Abstrak— Sungai Lembing merupakan kawasan perlombongan bijih timah yang diusahakan oleh syarikat Pahang Consolidated Company Limited (PCCL) dari tahun 1906 hingga 1986. Akibat kejatuhan harga bijih timah pada tahun 1985, lombong ini semakin mengurangkan operasinya sehingga ditutup pada tahun 1986. Terowong di Sungai Lembing secara keseluruhannya adalah sepanjang 5 km dan merupakan perlombongan secara syaf. Semenjak penutupan itu, tiada langkah-langkah pemeliharaan dan pemuliharaan dilakukan. Kerajaan negeri Pahang melalui Majlis Perbandaran Kuantan sedang giat memajukan kawasan ini sebagai kawasan pelancongan. Oleh itu, kajian penilaian kestabilan dan pemetaan terperinci bersama dengan pengelasan jasad batuan telah dilakukan. Pengelasan jasad batuan dilakukan sepanjang 520 m dalam terowong lombong dengan pengelasan Perkadaran Jasad Batuan (Rock Mass Rating, RMR). Sebahagian besar terowong telah dikelaskan sebagai kualiti III (sederhana) manakala pada bahagian tengah kawasan kajian berada dalam kelas IV (rendah) dan V (sangat rendah). Bagi kawasan yang berair, sistem saliran perlu dipasang pada bahagian tepi bukaan terowong untuk menyalurkan air keluar dari lombong. Kawasan yang mengalami jatuhan atau runtuhan skala kecil pula boleh dilakukan pengisian semula (back- filling) supaya keratan bukaan lebih sekata dan bagi kawasan yang mengalami runtuhan besar perlu dipasang kerangka konkrit berterusan (continuous cast concrete lining) bersama dengan sistem saliran air selepas pengisian semula dilaksanakan. Agar struktur batuan dalam terowong boleh dilihat dalam keadaan asal, langkah penggunaan crown bar atau forepole disyorkan. Kebanyakan bahan sokongan yang digunakan semasa lombong beroperasi dahulu terutama kayu sokongan pada bumbung terowong didapati telah tidak selamat digunakan dan perlu diganti dengan yang baru. Pemetaan ketakselanjaran dan struktur mendapati tiga struktur utama yang mengawal kestabilan terowong Sungai Lembing iaitu sesar, lipatan dan kekar. Lipatan rencam dirakamkan di Lokaliti 8 dan bahagian awal Lokaliti 9. Bacaan jurus yang diperolehi adalah mengarah hampir ke utara dengan purata nilai kemiringan sebesar 40° yang mewakili sayap barat satu sinklin yang besar. Sesar paling dominan dicerap di lokaliti L9R4. Keamataan kekar adalah tinggi disepanjang kesemua lokaliti yang dicerap. Keseluruhannya, daripada 19 lokaliti yang dipetakan, masih terdapat lagi terowong yang belum dipetakan disebabkan oleh faktor keselamatan dan memerlukan kajian lanjutan.
Kata kunci: sejarah perlombongan, kualiti jasad batuan, struktur geologi, pemuliharaan, Sungai Lembing
Abstract— Sungai Lembing was a tin mining area that was operated by the Pahang Consolidated Company Limited (PCCL) from 1906 to 1986. Due to the drop in the tin price during 1985, this mine wound down its operation until it was closed in 1986. Tunnels at Sungai Lembing have a total length of 5 km and the mine was operated as a shaft mine. After the mining operation was stopped, no conservation and preservation work has been done. The state government of Pahang through the Kuantan Municipal Council is developing this area for tourism. Hence, studies of tunnel stability and detail mapping including rock mass classification have been done. The classification of rock mass for 520 m of tunnel using the Rock Mass Rating (RMR) system was conduted. A large part of the tunnel is classified as class III (fair rock) while the middle part is class IV (poor) and V (very poor). For the flooded areas, a drainage system is needed at the side of tunnel to drain the water out of the mine. Small rock-fall areas can be rehabilitated by back-filling to make the tunnel opening more uniform and for large scale rock-fall continuous cast concrete lining and water drainage system after back-filling should be installed. For rock structure in the tunnel to be observed in its natural conditions, crown bar or forepole is suggested. Almost all support material from past operations especially timber support at the roof of tunnel is in poor condition and needs to be replaced. Mapping of discontinuities and structures found three main structures that control the tunnel stability at Sungai Lembing, which are faults, folds and joints. Complex folds were recorded at locality 8 and at the beginning of locality 9. Strike direction is to north with average dip value of 40˚ and represents a major syncline limb at the west area. A dominant fault was observed at locality L9R4. Density of joints is high at all localities. Overall, a total of 19 localities were mapped, but some parts of the tunnels still cannot be mapped because of safety concerns and need further study.
Keywords: mining history, rock mass quality, structural geology, conservation, Sungai Lembing
https://doi.org/10.7186/bgsm56201009
