In the past few months residents of Kiowa Valley and Skyline Ridge have contacted me with concerns about the blasting activity in the Skyline Ridge development. Because this seems to be a growing concern amongst residents, I thought it would be helpful if I provided some information for all. For those unfamiliar with the Skyline Ridge development, it is the new housing development in Kiowa Valley off of Golden Eagle. There are two phases of this development with the first nearing full build out.
In order to excavate approved lots, it was necessary for the developer to utilize blasting to break up the rocky ground. It will also be necessary for the second phase to use blasting to complete excavation when that phase starts. With the first phase, some of that blasting has been in close proximity to homes and understandably, has raised residents’ concerns over safety, and potential damage to property. I understand the concerns from residents, and I would like to share with you both what I know, and what I have done as a result.
There have been a total of eight individual blasts, all of which are associated with the first phase of the development (again, the second phase has not yet started development). Two of the eight blasts were in 2016 and six were in 2017. The blasting is a closely controlled activity which is permitted through Unified Fire Authority. After receiving approval, the UFA bomb/explosives technitian inspects the plan for safety and monitors results and blasting activity. With each blasting event, the blasting company or a third party engineering firm will place seismic monitoring equipment around the site to measure and record the force of the blast event.
For all of the eight blasting events to this point, the seismic energy generated has been within industry accepted standards. As you might imagine, the recording of the seismic energy is of the utmost importance to the developer, to the blasting company and also to the City. Safety of both person and property are important to all parties. The recording of the seismic energy released allows for safety performance to be monitored and verified.
The blasting that has taken place so far has been, at times in close proximity to existing homes. This of course adds to the concern that residents have. When I learned of the close proximity, I too was concerned. Prompted by residents concerns and a few of my own, wanted to understand exactly how the process worked and what was going to occur. I called our UFA Bomb Tech who issues the permits and asked him many questions about the permitting process, the monitoring, the Thresholds, etc. I then spoke to our City Engineer about development plan and excavation permit before going out to the site and meeting with the developer, the UFA Bomb Tech, the blasting company, and the third party engineering firm conducting the seismic monitoring.
I was first made aware of concerns when preparation began for a blasting event which was particularly close to an existing home (within approximately 50ft of the home). Naturally, I was surprised that the blasting was so close. I was equally surprised that the home had been built before the blasting had occurred. I was informed that there had been blasting in the area, but that the excavation near the home in question led to the discovery of rock which could not be removed by standard excavation process. My inquiries into the process and safety measures occurred before this particular blasting event moved forward.
While I was not thrilled that blasting was being conducted in such close proximity to homes, my observations of the process and controls in place alleviated my concerns for safety of our residents and their property. Having said this, I did relay to the developer that my strong desire was to complete all blasting far enough in advance of building activity as to prevent such issues from arising in the future.
For this particular blasting event, I was on site for the blast about 200 yards from the blast site. The blast was so small and so quiet in this instance that I didn’t know it had occurred. I was standing outside expecting the blast. I heard the warning horn and was expecting the blast, but did not hear or feel anything. I didn’t know it had occurred. Not all blasts are like this, and many of them create a subterranean blast wave that can be felt, and an audible boom. To that point, each blast is different and is engineered very carefully for a specific purpose. In the case of the blast close to the home, it was intentionally small in order to avoid damage to nearby homes. Other blasts further from structures can be larger and safely break up rock without threatening damage to homes or other structures.
While I am by no means an explosives expert, I am a certified nerd and an inquisitive person. Beyond this, I think it is my responsibility to look out for the well being of residents. As a result, I have sought out accurate information about explosives use in excavating, and how such activities can be controlled in such a way as to mitigate most of the risk. If you don’t care about the technical aspect of controlled explosives, you may not care to continue. For the rest of you, here are some details.
Explosives today are far more complicated than what you might have seen in an old western movie where the railroad workers place a bundle of dynamite next to a rock face, then light the fuse and run for their lives. Today, there are many factors which go into the design of a blast. After assessing environment and the risks of the blasting event. Some of these factors are the presence and distance to structures, the type of rock being blasted, the presence of ground or surface water, the location of utilities, etc. The blast is then designed to control risk. The factors that determine the characteristics of the blast include the type of explosive used (chemistry of the explosive), the depth and diameter of bore hole (where the explosive is loaded), the spacing of the bore holes, and the sequencing of the blast, and the timing of the sequential blasts. The variables of the blast design are used to manage the behavior of the energy released, accomplishing the desired work of breaking the rock where intended without releasing damaging energy where it is not intended. You can learn much more about explosives at www.explosives.org if you are interested. There are some interesting videos on that site as well.
At the conclusion of the blasting event, I did visit with residents in the neighborhood closest to the blast. I found residents to be understanding of the need for the blasting, though a little annoyed at the inconvenience of it. I did speak to one resident who had concerns about the potential of the blasting to dislodge rock from the hillside above their home. I shared this residents concern and relayed to the developer that I would like to see some additional work completed to perform some additional earth work to remove rocks and to further shape the hillside for safety. I have since revisited the site and will do so again to verify that the work is completed to address specific concerns.
In conclusion (to a very long blog post) I have asked that any additional blasting be completed as soon as possible and if multiple blasting events are necessary, that they be done at the same time if possible. Since that time there have not been any additional blasting events. There may be one more blasting event with this first phase of development. It is unknown how many blasting events will be needed for the second phase, though the second phase should be completed much further away from existing structures. If any resident in the Kiowa Valley / Skyline Ridge development has different perspective or remaining concerns, I always welcome your perspective.