Collectibles--General (Modern)/Porcelain Insulators
I was reviewing my notes and one shard does have some numbers: 73-994. This shard (first photo) is from a sequence that you indicated was much more modern.
In addition, one of the power pole features had a rusted metal band that reads "W * M.B.B. Made by America" I do not know if this is helpful or not, but we assume it was part of the transmission line. See photo 2.
To answer your question, the transmission line is on federal property, and there is a proposal to put a new highway through there. Under the National Historic Preservation Act, we are trying to recover all important information before any development occurs that could damage a historic property, and to make an assessment as to whether or not the site is eligible for listing on the National Register. Our report will be filed with the BLM.
Hi Jerry --
Sorry for the delay. From the shards you sent so far, the earliest appears to be 1920's vintage. The shard you show above is relatively modern, probably from the 1960's or newer. I'm not sure about the metal strap, it is not something I'm familiar with. As an insulator collector we consider any power lines that are pre 1910 to be historic. By the 1920's they were pretty common place unless there is some other mitigating circumstance. If you can send pics of more shards (maybe a group shot) with focus on pieces with brown glaze I can see if there is anything older.