Environmental value losses as impacts of natural resources utilization of in coal open mining

Mining industry provides benefits to the state in mining as a source of state revenue and foreign exchange earner, producing raw materials for the industrial, infrastructure and socio-economic facilities, and employment providers. Utilization of natural resources in openly coal mining in the forest did to get these benefits, but on the other hand cause environmental harm. Land clearing activities in coal mining, open forest vegetation is causing the loss of economic benefits of forest. Exploitation of coal caused the shrinking amount of coal (coal depletion). Although revegetation activities have been conducted on coal mined land, those would still cause harm to the environment. The research conducted at the site of coal mining PT Bukit Asam (PTBA) South Sumatra Indonesia using quantitative methods of Net Present Value (NPV) aims to assess the value of environmental damages incurred as a result of the utilization of natural resources in coal strip mine in forest areas. The calculation of forest benefit in and after the forest recovery period is using time dimensions that has innovated in this study. The results found for the environmentalloss duringlife of mine for a period of time 1997-2023 PV 2009 amounted to Rp


Introduction
Environmentally sound development becomes an important requirement for any nation that wants the preservation of natural resources. Therefore, natural resources need to be preserved and maintained for the survival of human kind in the present, and for the next generations. Forest destruction has led to reduction in the value of forest benefits.
Damage of the forest will also damage its ecosystem and its surrounding areas, as well as destroying all living systems. According to Reference [1] a lot of forest ecosystem services value clearly can not be known its monetary value. The impact of these policies affect the forest use, including for open pit coal mining activities more consider the financially benefits, so that the rate of degradation become faster.
Constanza et al.
[1] stated that the increased of degradation threatens the value of the benefits of forest ecosystems. Use of natural resources by open mining coal land clearing activities and coal exploitation activities pose a negative externality on the function of forest ecosystems, such as forests function as a provider of natural resources such as timber resources and coal resources contained in the forest.
The loss of this function results in loss of economic benefit to the forest so that the resulting loss of forest and coal depletion. Revegetation activities on coal mined lands to forests provide economic benefits in the form of the benefits of revegetation. But unfortunately coal mining activity in Indonesia including PT Bukit Asam South Sumatera not account for the losses suffered as a result of the loss of forest and coal depletion. Similarly, the value of the environmental benefits derived from the activities of revegetation.
In accordance with this study seem it necessary to assess economic losses of natural resources and the environment due to the use of natural resources in coal mines open in logged-over secondary forests on coal stock loss and the loss of value of the economic benefits of forests.

Methodology
Based on field investigation, the research conducted is environmental filed. Research conducted by surveys directly to the field of TAL PTBA to verify the secondary data obtained by instasional studies, and direct observation conducted to examine the effects of externalities of coal mining activities on the environment. Instational Survey conducted by visiting institutions associated with this study.
The population of study is a block of the mines in the coal mine site PTBA which consists of (1) Tambang Air Laya (TAL), (2) Tambang Bangko Barat (TBB), (3) Tambang Muara Tiga Besar (MTB). Samples were taken in Tambang Air Laya block. Sample determination is conducted by purposive sampling [8]. Determination based purposive sample on consideration of: (1) how long the PTBA coal mining blocks has been mined and reclaimed; searched the first block mined and reclaimed, and to know the influence of the distribution of the effects of these activities on the environment.
The study is a quantitative method to calculate the net present value (NPV) of the benefits and costs associated with the externalities of the utilization of natural resources in the open pit coal mining to the environment. Broadly speaking, the calculation of depletion and degradation of natural resources has been done in previous studies. In this study, the calculation of depletion of natural resources is still being done on coal resource depletion calculation and standing timber logged-over secondary forests. The development of the previous studies is to provide an economic assessment of forest loss, the study calculated the dimension of time is when the forest opened up the forest revegetation approach requires its original estimated recovery time for 15 years.

Economic loss
The economic value of each component (the value of coal depletion, loss of forests, indigo benefits of revegetation) next calculated the present value (present value) in 2009. Present value to the value of each component are summed to obtain a total economic value (NET) loss of natural resources and the environment due to the use of natural resources in the coal mine open.
Calculations are made up of natural resource depletion and environmental losses, the benefits of revegetation on coal mined lands and forest benefits to n after the end of revegetation activities on coal mined lands (during the recovery period of 15 years), with the calculation of the time dimension is a unitary concept of determination environmental losses due to natural resource use coal strip mine the state of the art in this research complements a lack of previous research studies lack.
Value of forest loss is not taken into account only in the dimension of space, but also with the calculation of time dimensions (15 years), adjusted to the time of recovery (restoration) secondary forest logged over to approach its original state, and the mature eucalyptus plants are most abundant in the location TAL PTBA and can be extracted as eucalyptus oil, as well as the loss values for each component and forest benefits over the life of the mine and the benefits of forests to t years after the end of the forest restoration activities carried out calculations to obtain the present value of the total economic value as the novelty of this study are as follows: a. Value of coal depletion (1)

Calculation methode of value of forest benefits
Valuation losses of natural resources and environmental externalities arising from the use of natural resources in the open pit coal use calculation methods that have been modified from previous studies [10] and those found in this study. Method of calculation used to determine the percentage of forest benefits revegetation approach for the 15-year secondary forest recovery. Percentage revegetation approaches do given the plant to become mature through the process of growth each year. 15-year time horizon used is based on eucalyptus plants most dominating in the area of revegetationat TA PTBA can be extracted to be taken advantage at the ripe age of 15 years, and according to [7] it would take 15 years for the recovery of logged-over secondary forests in the TAL PTBA site. Value of environment benefits obtained from each year revegetation percentage for 15 years time horizon. Similarly for the year to 16 and so on for the operational life of the mine will continue to value the environmental benefits obtained in a sustainable manner. If the value of the benefit during forest restoration continues to increase each year in accordance with the process of plant growth up to 15 th year (the printed image and his broken red line), then for n years after the end of the recovery period (16 th year an so on) a decline in the value of benefits cumulative environmental (printed lines and blue arrows). It is assumed that with the increasing age of the plant after the mature will decrease the ability to be productive. The diagram of growth process and counting revegetation of forest benefits during forest restoration, and year after the recovery period) in TAL Location PTBA is shown in Figure 2.  c. Value of forest benefit.
Forest is a natural resource which is very important and useful for life and living either directly or indirectly, that contains the value of services for the life of the environment service. Previous research by [9] stated to get the value of 1,835.83 U.S. $ / ha/ year as value of secondary forest services in Indonesia. Similarly, research in Thailand by [4] suggests a value of USD 756.16/ha/year obtained from externalities reforestation with type Eucalypthuscamaldulensia. Compensation for people who lost access to the forest of USD 673,000 per year and the value of farmers' losses due to the flood of USD 71,000 per year in Madagascar shows the value of environmental services of forests [3]. Value of the external benefits in this study was obtained from the benefits of revegetation at the TAL PTBA site. Revegetation activities at TAL PTBAsite are performed each year in accordance with the annual plan of environmental management of TAL PTBA. Revegetation activities is calculated by assuming that (1) the economic value of plants emerged a yearafter the implementation of revegetation activities initiated by 15year recovery period, (2) After 15 years of restoration at the TAL PTBA site, revegetation activities not yet done, and no logging activity, but the forest still preserved until coal post-mining, so in year 16 and post-mining coal revegetation activities still providing value of benefits.
The calculation of the benefits of forest each year in TAL PTBA coal mines using equation 6 Assessment of natural resources and environmental losses due to natural resource utilization activities of coal open mining can be applied by: 1) Government as policy makers should internalize the environmental cost into coal mining feasibility study using open pit methods. The Government, should implieda policy to internalizethe external cost (environmental cost) in the feasibility study of coal mining activity with open pit method, 2) Openly coal mining business in general should determine the value of losses incurred as externalities of coal open mining activities.

Conclusion
The calculation of forest benefit in and after the forest recovery period is using time dimensions has been innovated in this study. The results found for the environmentalloss during life of mine for a period of time 1997-2023 PV 2009 amounted to Rp 73.98 trillion,. The results of this study indicate that such large losses suffered as a result of the utilization of the open pit coal mining apart due to the loss of forest resources worth 834 billion rupiah also caused the loss of coal stock in the nature worth 73.47 trillion rupiah. With the findings of this study should coal mining operation account for losses arising as environmental externalities of natural resource utilization activities of coal open mining.