Evaluation of coal bottom ash properties and its applicability as engineering material

Coal ash is obtained in the combustion of coal for electricity production in coal based power stations. The non-combustible by-product including bottom ash and fly ash are discarded as a landfill. Consequently, the hazardous elements contained in the ashes can adulterate the ground and surface water. This study was carried out to emphasize the engineering properties of bottom ash collected at Tanjung Bin power station. An experimental study was carried out for particle size analysis, specific gravity, shear strength, compaction and relative density. The results depict that bottom ash possess particle size distribution nearly identical to sand, low specific gravity and dry density as compared to natural soil and having higher internal friction angle closer to granular materials. Based on the results, bottom ash can be employed in roadways, embankments and filling material for retaining walls by virtue of its low specific gravity, easy to compact and good frictional characteristics

Symplocos buxifolia

Symplocos buxifolia is a small tree, endemic to Sabah. The estimated area of occupancy (AOO) and extent of occurrence (EOO) are both 32 km2. Although the AOO is calculated from known existing records, it is considered that the actual AOO may be considerably larger than this due to under sampling. It is found scattered around Mount Kinabalu, and currently facing no major threat to its population. It is assessed as Least Concern. Symplocos buxifolia is endemic to Sabah, Malaysia. It is known from Mount Kinabalu

Symplocos deflexa

Symplocos deflexa is a small tree, endemic to Sabah. The estimated area of occupancy (AOO) and extent of occurrence (EOO) are 28 km2 and 34.5 km2, respectively. Majority of the records of this species are from Kinabalu Park, a protected area. There is no immediate threat to this species. Hence, it is assessed as Least Concern. Symplocos deflexa is endemic to Sabah, Malaysia. It is known from Tenompok, Mount Kinabalu and the local vicinity, Ranau

Symplocos zizyphoides

Symplocos zizyphoides is a treelet, endemic to Sabah. The estimated area of occupancy (AOO) and extent of occurrence (EOO) are both 32 km2. There is no major threat as the species is recorded abundantly in Mount Kinabalu. It is assessed as Least Concern. Symplocos zizyphoides is endemic to Sabah, Malaysia. It is known from Mount Kinabalu, Ranau

Pittosporum peridoticola

Pittosporum peridoticola is a rare species of shrub recorded only from Mount Kinabalu and Mount Tumbuyukon. To date, the estimated area occupancy (AOO) and extent of occurrences (EOO) are both 8 km2 respectively. The species is known from two locations. This species is recorded to occur in ligneous scrub on extreme ultramafic soil in montane forest, therefore the most plausible threats that could affect the population would be climate change and landslides. If these were to occur, they could drive the species towards Critically Endangered or Extinct in the near future. Hence, it is assessed as Vulnerable. Pittosporum peridoticola is endemic to Sabah, Malaysia. It is only known from Mount Kinabalu and Mount Tembuyuken

Aglaia sessilifolia

Aglaia sessilifolia is a tree, endemic to eastern Sabah. Due to land use changes the remaining known population is in Kabili Sepilok Forest Reserve, Sandakan. It is suspected that there has been 80% population decline in two generations (based on GeoCAT reduction analysis). The remaining estimated area of occupancy (AOO) and extent of occurrence (EOO) are both 4 km2. The occurrence of the species in a well protected area means decline is not continuing. This species is assessed as Critically Endangered. Aglaia sessilifolia is endemic to Sabah, Malaysia. It is recorded from the eastern part of the state

Xanthophyllum montanum

Xanthophyllum montanum is a large tree recorded from Mount Kinabalu and Sosopodon Forest Reserve. To date, the estimated area of occupancy (AOO) and extent of occurrence (EOO) are both 16 km2 respectively. The species is recorded to occur in lower montane forest in brownish soils, therefore, the most plausible threat that could affect the population would be land use change and climate change. However the species historically experienced population decline of between 50 and 69% due to land use change and decline in AOO and EOO. Therefore, the species is assessed as Endangered. Xanthophyllum montanum is endemic to Sabah, Malaysia. It is restricted to Mount Kinabalu and Sosodopan areas. The species has experienced decline in area of occupancy and extent of occurrence, however, the remaining individuals are mostly within protected area or near boundary of a protected area

Melastoma ansowii

Melastoma ansowii is a treelet endemic to Sabah, Malaysia. It is only known from Mount Kinabalu and vicinity. The estimated area of occupancy (AOO) and extent of occurrence (EOO) are 20 km2 and 27.3 km2, respectively. The most plausible threats that could affect the population of this species are climate change and land use change. Montane species are more susceptible to extreme climate, while individuals outside of protected areas are threatened by land use changes. This species can withstand disturbance but not land clearing. If these were to occur, they could drive the species towards Critically Endangered or Extinct in the near future. Hence, it is assessed as Vulnerable. Melastoma ansowii is endemic to Sabah, Malaysia. It is confined to Mount Kinabalu and vicinity

Xanthophyllum longum

Xanthophyllum longum is only known from Sg Pinangah Forest Reserve (commercial forest reserve) in Sabah. The estimated area of occupancy (AOO) and extent of occurrence (EOO) are both 4 km2 the species has experienced a reduction of AOO (67%) and EOO (over 90%). Although the species is not on the harvested timber list and reduced impact logging protocol is being practiced within the forest reserve, the decline of habitat quality is still plausible, hence the species is assessed as Critically Endangered. Xanthophyllum longum is endemic to Sabah, Malaysia. Based on herbarium record it is confined to Sg Pinangah Forest Reserve. Due to urbanization and past historical events the species has experienced reduction of in area of occupancy (AOO) of 67% and extent of occurrence (EOO) of over 90%, resulting in the current AOO and EOO for the species to be 4 km2 respectively

Porterandia postarii

Porterandia postarii is a tree endemic to Sabah, Malaysia. It is found in ultramafic forests across the state. There are no major threats to this species, as all localities are within totally protected areas. Hence, it is assessed as Least Concern. Poterandia postarii is endemic to Sabah, Malaysia. It is found in ultramafic forests across the state