Definition of "countermine"

Normally the threat would have been dealt with by means of a counter-mine, but the tunnel was now far too close for that.

1990, Peter Hopkirk, The Great Game, Folio Society, published 2010, page 436

Thinking himself contemned, knowing no countermine against contempt but terror.

a. 1587, Philippe Sidnei [i.e., Philip Sidney], “(please specify the page number)”, in Fulke Greville, Matthew Gwinne, and John Florio, editors, The Countesse of Pembrokes Arcadia [The New Arcadia], London: […] [John Windet] for William Ponsonbie, published 1590; republished in Albert Feuillerat, editor, The Countesse of Pembrokes Arcadia (Cambridge English Classics: The Complete Works of Sir Philip Sidney; I), Cambridge, Cambridgeshire: University Press, 1912,

[…] every gamester will agree how necessary it is to know exactly the play of another, in order to countermine him.

1749, Henry Fielding, chapter III, in The History of Tom Jones, a Foundling, volumes (please specify |volume=I to VI), London: A[ndrew] Millar, […], book VI

[…] so Fritz could sleep easily in his trench, so far as mines were concerned; and Fritz, confident in his Herr Professors, altogether neglected any attempt to counter-mine.

1923, Frank Fox, “The Man-Made Earthquake”, in Charles Francis Horne, The Great Events of the Great War‎, volume 5