Agenda Packets - 1995/02/06 - Laserfiche WebLink

Home Browse Search

t• '§•. Iane of underground space beneath private land depends on several factors: ash tli " s,"4!:;_; is Are mineral resources of value involved? normal use of the surface land be affected? Will the construction of future structures be limited by any underground use? • How accessible is the underground zone? of Is it likely that this zone would or could be developed by the current owner? }4.tg., What is the cost of developing the underground zone? 77.14/-77.14/- "Is the actual underground space utilized dependent for its stability on an undisturbed zone of this r ground around the opening? we t S. Is there an psychological impact on land value from partial undermining? :red • • �e-of-mineral-resources-is-neglected factors 2-through 5 indicate-that-the value-of underground space should tend to decrease with increasing depth and decreasing impact on surface uses, If the land surface is effectively usurped, then one would expect the cost of the underground oh space to equal the full cost of the surface land required. With decreasing impact on the current and Mute uses to which the surface land may be put, the loss in land value to the owner of the surface >wer land diminishes. Such a decreasing impact may be expected to occur with increasing depth. Also, the owner is less likely to want to or to be able to develop the underground space at greater depths. the For the developer of the underground space, the principal issues are 4 and 6. The underground space is not useful if it is not accessible and the price the developer is willing to pay for the right to the space will be related to the cost to develop the underground zone in question. If other costs are fixed, cheaper construction costs will allow a higher price to be paid for the space. Construction costs generally will tend to increase with depth below ground reinforcing the other factors mentioned above. This will not always be the case, however. In cases where different geological formations provide substantially different costs for excavation and support of underground openings, costs to construct underground space may be less in favorable geological formations at greater depth than in • poorer shallow conditions. This lower construction cost may result in an increase in the value of underground space within this favorable zone. An analysis and discussion of the interaction between • land cost and the cost/benefit analysis for underground versus aboveground buildings is provided in Carmody and Sterling (1993). to When considering the cost of an easement or land purchase for underground development it is important to take into account any additional ground or land area required for the support of the underground excavation made. Many underground structures are designed based on the interaction of the structure and the surrounding ground and it may not be possible to build a new structure immediately adjacent to the previously constructed facility without extensive strengthening work. This restriction on the future use of the ground surrounding the current use should be included in calculating the value of the easement and it should be clear whether the value assigned is for the actual area occupied below ground or the total area necessary to maintain the stability of the structure. There also may be cost impacts on the value of surface land due to underground easements which are not as readily determined. When easements are created or underground structures exist beneath a 13