
597 P.2d 1252 (1979)
41 Or.App. 349
Jean HARRINGTON, Petitioner,
v.
OREGON STATE PENITENTIARY, CORRECTIONS DIVISION, Respondent.
No. 02-79-110; CA 13693.
Court of Appeals of Oregon.
Argued and Submitted June 21, 1979.
Decided July 30, 1979.
David E. Groom, Public Defender's office, Salem, argued the cause for petitioner. With him on the brief was Gary D. Babcock, Public Defender, Salem.
J. Scott McAlister, Asst. Atty. Gen., Salem, argued the cause for respondent. With him on the brief was James A. Redden, Atty. Gen., and Walter L. Barrie, Sol. Gen., Salem.
Before SCHWAB, C.J., and LEE, GILLETTE and CAMPBELL, JJ.
GILLETTE, Judge.
In this prison discipline case, petitioner was charged with and found guilty of violations *1253 of prison disciplinary Rule 1 (OAR 291-40-050(1))  Disruptive Behavior[1] and Rule 13(a) (OAR 291-40-050(13)(a))  Conspiracy to Commit a Rule Violation.[2] We affirm.
This is another of the cases arising out of a concerted work stoppage or sit-down strike which occurred at the Oregon State Penitentiary beginning on February 7, 1979. See Calhoun v. OSP, 41 Or. App. 339, 597 P.2d 1250 (decided this date). As was true in Calhoun, the record here is sparse. It is sufficient, however, to establish that petitioner was an actual participant in the work stoppage in the prison laundry on the day in question. Accordingly, his conviction for violation of Rule 1 is affirmed. See Calhoun v. OSP, supra.
Respondent argues, and we agree, that  at least under the circumstances of this case  the disciplinary committee was entitled to find petitioner's public joining of the strike constituted "conspiracy" as that term is defined in Rule 13(a), viz., "* * * an agreement with any other person(s) to * * engage in or cause rule violations." The joint action of petitioner and the others permits the reasonable inference of an actual, even if unspoken, agreement to stop work at the prison.
Petitioner relies on Robertson v. OSP, 35 Or. App. 591, 582 P.2d 32 (1978), but that case will not aid him. Robertson involved a discussion of a possible sit-down strike between inmates. The discussion never resulted in any agreement. Here, by contrast, there was a strike. Strikes are concerted actions; agreement lies at their heart. The committee was entitled to view petitioner's act of joining the strike as a manifestation of an agreement.
Affirmed.
NOTES
[1]  OAR 291-40-050(1) provides;

"Disruptive Behavior. No inmate shall engage in the advocation, encouragement, promotion, or creation of a disturbance.
"A `disturbance' is a substantial disorder characterized by unruly, noisy, or violent conduct which disrupts the orderly administration of the institution or creates an unreasonably annoying condition which poses a direct threat to the security and/or safety of the institution."
[2]  OAR 291-40-050(13)(a) provides:

"No inmate shall enter into an agreement with any other person(s) to:
"(a) Engage in or cause rule violation(s); * * *"
