Trinidad lake asphalt is well known for its durability and stability. However, there is another location where natural asphalt has been mined since 1920. It is Buton Island, South East Sulawesi Indonesia. The mining was poorly managed, and efforts have been done to gain new innovation to explore the potentials of Buton Natural Asphalt efficiently, and to enable Buton Natural Asphalt to compete with Asphalt modified from kerosene
Asphalt is a key material in constructing roads in Indonesia. But it has low durability due to the condition of the infrastructure and the nature, e.g flood, the sun heat of a tropical country, and the heavy weight from the vehicles. These problems made the contractors use concrete with metal frame, although this kind of method is relatively more costly and involve difficult process.
Compared to concrete, choosing natural asphalt has more benefit. The most well known natural asphalt is TLA (Trinidad Lake Asphalt). However, the forgotten one, Buton Natural Asphalt is able to compete with TLA in Quality.
Although the stock of Buton Natural Asphalt are abundant, the mining location was left since 1970, because operational costs is not balanced with the benefit.
‘The real problem is extraction technique implementation or conventional purifying process which is not efficient,’ Lisminto said in one interview. Lisminto is the inventor of a new purifying technique for Buton Natural Asphalt.
In the old technique used in Asphalt purifying process, the bitumen is dissolved in an organic solvent, then the material is separated from the solvent using distillation process.
This way, it is difficult to drag out the bitumen or the asphalt material, hidden in the host rock matrix. Therefore, they need an extractor with multiple stages. And it simply means more investment
Lisminto is a bachelor of Chemistry Engineering of Bandung Institute of Technology (ITB), the best Engineering school in Indonesia. He was able to invent new technique, using a particular solvent for asphalt dissolution, and he uses sea water as a medium in the purifying process.
When the host rock breaks, the bitumen will be separated automatically, and floats in the salt water. Therefore, the bitumen is easily separated using this process. This process is done within the atmosphere temperature and pressure, so it will minimize the material burning. Simple, easy, and cheap, that’s the strength of this technique, that Luminto calls Buton natural Asphalt purifying process using reversed extraction technology.
This innovation is not a new technology apparently, because it was patented by Indonesia, Japan, and Australia’s patent institute in 1996.
The implementation of this technique will save up to 75 million USD, because it only costs 25 Million USD, by doing the fabrication domestically. Whereas using other technology might cost 100 million USD.
The use of domestic mine resource will also minimize asphalt import up to 1 million to per year, to create self-supporting asphalt source for Indonesia. This is because the reversed extraction technology, is able to produce affordable high quality asphalt.
Although this innovation has a great social and business prospect, the government and the companies are somewhat not welcoming this effort. It doesn’t make Lisminto give up. Consistently, he’s been working closely with his research on asphalt, and the plant.
The pilot plant which had 1 million capacities per hour, was successfully constructed, and this costs Rp 200 million. The product was tested by puslitbang (Indonesian research and development center) and it was acknowledged as high quality asphalt. Lab and field examination showed that Buton Natural Asphalt has the same features and characteristics that TLA has.
Moreover, this process produces byproducts; they are gypsum, and CO2. Gypsum is the main material for cement, which is still imported by Indonesia for 2 million tons per year. And CO2, can be converted to be dry ice, to preserve fish. From each ton of asphalt, we can get 1,45 tons of Gypsum, and 0,47 tons of dry ice.
From continuous asphalt development since 15 years ago in a lab and a plant that they called ‘Rumah Teknology aspal” or ‘House of Asphalt technology’, they have been able to address five problems that they encounter from Buton natural Asphalt, they are adhesivity, difficulties in processing Buton Natural asphalt, compaction, flexibility, and distribution obstacles
The result of processed natural Asphalt in Buton, is called BNA or Buton natural Asphalt, which was designed as TLA’s clone.
This product, attracted some companies to be partners, they are Adhi Jaya, Pertamina, and PT Timah (Persero).
Pertamina was interested to be involved in this development and now PT Agroyasa has been appointed as one of Distributors.
The BNA (Buton natural asphalt) development, is expected to follow TLA’s ‘success story, which proved to be reliable construction material for more than 100 years.