不确定条件下矿产资源的最优开采

Optimal Exploitation of Nonrenewable Resource under Uncertainty

通过一个连续时间的随机动态规划模型,探讨了市场需求、资源存量的不确定性以及勘探活动对矿产资源价格和开采速度的影响,并给出了随机条件下Hotelling法则的表达形式。模型结果显示:不确定性对资源价格变化速度的影响主要取决于开采成本,如果相对于资源存量来说开采成本是不变的或者开采的规模成本是不变的,则不确定性对资源价格的变化速度没有影响。反之,如果开采的规模成本是递增的,则不确定性会加速资源价格的变化。此外,不确定性的存在将加快资源的开采速度。至于勘探活动,它一方面降低了地质条件的不确定性,另一方面增加了资源的存量,所以勘探活动降低了资源价格和开采速度的变化率,减少了不确定性对资源开采的影响。

This paper prevented a general model for the optimal exploitation of a nonrenewable resources under the two kinds of uncer-tainties. One source of uncertainty was in the reserve level and the other was in the economic environment that affected resource supply and demand condhions. This paper showed that the Hotelling＇s rule still applied and the demand uncertainty didn＇t effect on the expected dynamics of market price, while reserve uncertainty shifted the expected rate of change of price only if extraction costs were nonlinear in reserves. The model was also extended to include exploration, first as a means of reducing uncertainty and second as a means of accumulating reserves, with uncertainty over the future response of discoveries to exploration effort.