2018 Update #21

Test Blast Scheduled for Weds; Here’s What to Expect

I hope everyone enjoyed the Memorial Day Weekend and the official start to Summer 2018.

Now it’s back to work!

As I mentioned in Friday’s update, Maine Drilling & Blasting expects to conduct a test blast in Printer’s Alley this coming Wednesday, May 30. Most likely it will take place in the afternoon.

The purpose of this test blast is to level the working area in Printer’s Alley while testing the bedrock that must be removed to construct the new drainage system.

As you might imagine, there is a strict protocol to follow during a blasting event. Here are some things to know.

What the Whistles Mean

A whistle warning sequence will be sounded prior to commencement of the blast to alert those in the area that a blast is imminent. Here’s what that sequence signals:

4 whistles = we’re 20 minutes out from the blast

3 whistles = 5 minutes to go

2 whistles = 1 minute to go

1 whistle = All clear

Impact on Downtown Pedestrians and Traffic

Maine D&B will have 18 individuals in reflective vests and hard hats posted at key points around a perimeter leading into Printer’s Alley to ensure that no one enters the blasting area once the 5-minute countdown has begun. For example, if you’re walking up Main Street to the Post Office or from Marble Works Pharmacy to Main Street you’ll be asked to wait a few minutes until the blast has taken place.

At the same time, flaggers will briefly halt traffic on Main Street during the blasting event.

The entire team monitoring pedestrian and traffic flow will be in radio contact with one another. If there is any compromise of the blast perimeter, the blast will be called off.

Maine D&B is meeting individually with the buildings and businesses that immediately adjoin Printer’s Alley to review the blasting protocol. The impact of ground vibrations from the blast on these buildings will be closely monitored in real time via seismograph machines and other devices to ensure that ground vibrations do not exceed established limits that could potentially cause damage.

I’m told that the blast itself takes place in a split second. Large blast mats currently sitting alongside the rail line in the Marble Works will cover the blast area.

That pretty much covers what I’ve learned in advance of this first test blast. Let me know if you have any questions or concerns.

That’s all for today. See you downtown.

Please keep your comments and questions coming. Send me an email at jgish@townofmiddlebury.org and I’ll try to cover it in my next update.