microtunnelling1
/ˌmʌɪkrə(ʊ)ˈtʌn(ə)lɪŋ/noun
The formation or construction of extremely small-diameter tunnels, especially (in Engineering ) the mechanical excavation of such tunnels, which are typically used for pipe-laying.
Origin
1980s; earliest use found in Soviet Materials Science. From micro- + tunnelling.
microtunnelling2
/ˌmʌɪkrə(ʊ)ˈtʌnlɪŋ/adjective
Of, relating to, or designating the formation or construction of very small-diameter tunnels or channels, especially (in Engineering ) the mechanical excavation of such tunnels, e.g. for pipe-laying. Usually attributive.
Origin
1980s; earliest use found in Japan Telecommunications Review. From microtunnelling; compare -ing.